neovim/src/nvim/eval/funcs.c

// This is an open source non-commercial project. Dear PVS-Studio, please check
// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com

#include <assert.h>
#include <fcntl.h>
#include <float.h>
#include <inttypes.h>
#include <limits.h>
#include <math.h>
#include <msgpack/object.h>
#include <msgpack/pack.h>
#include <msgpack/unpack.h>
#include <signal.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include <uv.h>

#include "auto/config.h"
#include "nvim/api/private/converter.h"
#include "nvim/api/private/defs.h"
#include "nvim/api/private/dispatch.h"
#include "nvim/api/private/helpers.h"
#include "nvim/api/vim.h"
#include "nvim/ascii.h"
#include "nvim/assert.h"
#include "nvim/autocmd.h"
#include "nvim/buffer.h"
#include "nvim/buffer_defs.h"
#include "nvim/channel.h"
#include "nvim/charset.h"
#include "nvim/cmdexpand.h"
#include "nvim/context.h"
#include "nvim/cursor.h"
#include "nvim/diff.h"
#include "nvim/edit.h"
#include "nvim/eval.h"
#include "nvim/eval/buffer.h"
#include "nvim/eval/decode.h"
#include "nvim/eval/encode.h"
#include "nvim/eval/executor.h"
#include "nvim/eval/funcs.h"
#include "nvim/eval/typval.h"
#include "nvim/eval/userfunc.h"
#include "nvim/eval/vars.h"
#include "nvim/eval/window.h"
#include "nvim/event/loop.h"
#include "nvim/event/multiqueue.h"
#include "nvim/event/process.h"
#include "nvim/event/time.h"
#include "nvim/ex_cmds.h"
#include "nvim/ex_docmd.h"
#include "nvim/ex_eval.h"
#include "nvim/ex_getln.h"
#include "nvim/file_search.h"
#include "nvim/fileio.h"
#include "nvim/garray.h"
#include "nvim/getchar.h"
#include "nvim/gettext.h"
#include "nvim/globals.h"
#include "nvim/grid_defs.h"
#include "nvim/hashtab.h"
#include "nvim/highlight_defs.h"
#include "nvim/highlight_group.h"
#include "nvim/indent.h"
#include "nvim/indent_c.h"
#include "nvim/input.h"
#include "nvim/keycodes.h"
#include "nvim/lua/executor.h"
#include "nvim/macros.h"
#include "nvim/main.h"
#include "nvim/mark.h"
#include "nvim/math.h"
#include "nvim/mbyte.h"
#include "nvim/memfile_defs.h"
#include "nvim/memline.h"
#include "nvim/memory.h"
#include "nvim/menu.h"
#include "nvim/message.h"
#include "nvim/mouse.h"
#include "nvim/move.h"
#include "nvim/msgpack_rpc/channel.h"
#include "nvim/msgpack_rpc/channel_defs.h"
#include "nvim/msgpack_rpc/server.h"
#include "nvim/normal.h"
#include "nvim/ops.h"
#include "nvim/option.h"
#include "nvim/optionstr.h"
#include "nvim/os/dl.h"
#include "nvim/os/fileio.h"
#include "nvim/os/fs_defs.h"
#include "nvim/os/os.h"
#include "nvim/os/pty_process.h"
#include "nvim/os/shell.h"
#include "nvim/os/stdpaths_defs.h"
#include "nvim/os/time.h"
#include "nvim/path.h"
#include "nvim/plines.h"
#include "nvim/popupmenu.h"
#include "nvim/pos.h"
#include "nvim/profile.h"
#include "nvim/regexp.h"
#include "nvim/runtime.h"
#include "nvim/search.h"
#include "nvim/sha256.h"
#include "nvim/spell.h"
#include "nvim/spellsuggest.h"
#include "nvim/state.h"
#include "nvim/strings.h"
#include "nvim/syntax.h"
#include "nvim/tag.h"
#include "nvim/ui.h"
#include "nvim/undo.h"
#include "nvim/version.h"
#include "nvim/vim.h"
#include "nvim/window.h"

/// Describe data to return from find_some_match()
typedef enum {
  kSomeMatch,  ///< Data for match().
  kSomeMatchEnd,  ///< Data for matchend().
  kSomeMatchList,  ///< Data for matchlist().
  kSomeMatchStr,  ///< Data for matchstr().
  kSomeMatchStrPos,  ///< Data for matchstrpos().
} SomeMatchType;

#ifdef INCLUDE_GENERATED_DECLARATIONS
# include "eval/funcs.c.generated.h"

# ifdef _MSC_VER
// This prevents MSVC from replacing the functions with intrinsics,
// and causing errors when trying to get their addresses in funcs.generated.h
#  pragma function(ceil)
#  pragma function(floor)
# endif

PRAGMA_DIAG_PUSH_IGNORE_MISSING_PROTOTYPES
PRAGMA_DIAG_PUSH_IGNORE_IMPLICIT_FALLTHROUGH
# include "funcs.generated.h"

PRAGMA_DIAG_POP
PRAGMA_DIAG_POP
#endif

static char *e_listblobarg = N_("E899: Argument of %s must be a List or Blob");
static char *e_invalwindow = N_("E957: Invalid window number");
static char *e_reduceempty = N_("E998: Reduce of an empty %s with no initial value");
static char e_using_number_as_bool_nr[]
  = N_("E1023: Using a Number as a Bool: %d");

/// Dummy va_list for passing to vim_snprintf
///
/// Used because:
/// - passing a NULL pointer doesn't work when va_list isn't a pointer
/// - locally in the function results in a "used before set" warning
/// - using va_start() to initialize it gives "function with fixed args" error
static va_list dummy_ap;

/// Function given to ExpandGeneric() to obtain the list of internal
/// or user defined function names.
char *get_function_name(expand_T *xp, int idx)
{
  static int intidx = -1;

  if (idx == 0) {
    intidx = -1;
  }
  if (intidx < 0) {
    char_u *name = (char_u *)get_user_func_name(xp, idx);
    if (name != NULL) {
      if (*name != NUL && *name != '<'
          && strncmp("g:", xp->xp_pattern, 2) == 0) {
        return cat_prefix_varname('g', (char *)name);
      }
      return (char *)name;
    }
  }

  const char *const key = functions[++intidx].name;
  if (!key) {
    return NULL;
  }
  const size_t key_len = strlen(key);
  memcpy(IObuff, key, key_len);
  IObuff[key_len] = '(';
  if (functions[intidx].max_argc == 0) {
    IObuff[key_len + 1] = ')';
    IObuff[key_len + 2] = NUL;
  } else {
    IObuff[key_len + 1] = NUL;
  }
  return (char *)IObuff;
}

/// Function given to ExpandGeneric() to obtain the list of internal or
/// user defined variable or function names.
char *get_expr_name(expand_T *xp, int idx)
{
  static int intidx = -1;

  if (idx == 0) {
    intidx = -1;
  }
  if (intidx < 0) {
    char_u *name = (char_u *)get_function_name(xp, idx);
    if (name != NULL) {
      return (char *)name;
    }
  }
  return get_user_var_name(xp, ++intidx);
}

/// Find internal function in hash functions
///
/// @param[in]  name  Name of the function.
///
/// @return  pointer to the function definition or NULL if not found.
const EvalFuncDef *find_internal_func(const char *const name)
  FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE FUNC_ATTR_NONNULL_ALL
{
  size_t len = strlen(name);
  int index = find_internal_func_hash(name, len);
  return index >= 0 ? &functions[index] : NULL;
}

int call_internal_func(const char_u *const fname, const int argcount, typval_T *const argvars,
                       typval_T *const rettv)
  FUNC_ATTR_NONNULL_ALL
{
  const EvalFuncDef *const fdef = find_internal_func((const char *)fname);
  if (fdef == NULL) {
    return FCERR_UNKNOWN;
  } else if (argcount < fdef->min_argc) {
    return FCERR_TOOFEW;
  } else if (argcount > fdef->max_argc) {
    return FCERR_TOOMANY;
  }
  argvars[argcount].v_type = VAR_UNKNOWN;
  fdef->func(argvars, rettv, fdef->data);
  return FCERR_NONE;
}

/// Invoke a method for base->method().
int call_internal_method(const char_u *const fname, const int argcount, typval_T *const argvars,
                         typval_T *const rettv, typval_T *const basetv)
  FUNC_ATTR_NONNULL_ALL
{
  const EvalFuncDef *const fdef = find_internal_func((const char *)fname);
  if (fdef == NULL) {
    return FCERR_UNKNOWN;
  } else if (fdef->base_arg == BASE_NONE) {
    return FCERR_NOTMETHOD;
  } else if (argcount + 1 < fdef->min_argc) {
    return FCERR_TOOFEW;
  } else if (argcount + 1 > fdef->max_argc) {
    return FCERR_TOOMANY;
  }

  typval_T argv[MAX_FUNC_ARGS + 1];
  const ptrdiff_t base_index = fdef->base_arg == BASE_LAST ? argcount : fdef->base_arg - 1;
  memcpy(argv, argvars, (size_t)base_index * sizeof(typval_T));
  argv[base_index] = *basetv;
  memcpy(argv + base_index + 1, argvars + base_index,
         (size_t)(argcount - base_index) * sizeof(typval_T));
  argv[argcount + 1].v_type = VAR_UNKNOWN;

  fdef->func(argv, rettv, fdef->data);
  return FCERR_NONE;
}

/// @return  true for a non-zero Number and a non-empty String.
static int non_zero_arg(typval_T *argvars)
{
  return ((argvars[0].v_type == VAR_NUMBER
           && argvars[0].vval.v_number != 0)
          || (argvars[0].v_type == VAR_BOOL
              && argvars[0].vval.v_bool == kBoolVarTrue)
          || (argvars[0].v_type == VAR_STRING
              && argvars[0].vval.v_string != NULL
              && *argvars[0].vval.v_string != NUL));
}

/// Apply a floating point C function on a typval with one float_T.
///
/// Some versions of glibc on i386 have an optimization that makes it harder to
/// call math functions indirectly from inside an inlined function, causing
/// compile-time errors. Avoid `inline` in that case. #3072
static void float_op_wrapper(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  float_T f;

  rettv->v_type = VAR_FLOAT;
  if (tv_get_float_chk(argvars, &f)) {
    rettv->vval.v_float = fptr.float_func(f);
  } else {
    rettv->vval.v_float = 0.0;
  }
}

static void api_wrapper(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }

  MsgpackRpcRequestHandler handler = *fptr.api_handler;

  Array args = ARRAY_DICT_INIT;

  for (typval_T *tv = argvars; tv->v_type != VAR_UNKNOWN; tv++) {
    ADD(args, vim_to_object(tv));
  }

  Error err = ERROR_INIT;
  Arena res_arena = ARENA_EMPTY;
  Object result = handler.fn(VIML_INTERNAL_CALL, args, &res_arena, &err);

  if (ERROR_SET(&err)) {
    semsg_multiline((const char *)e_api_error, err.msg);
    goto end;
  }

  if (!object_to_vim(result, rettv, &err)) {
    semsg(_("Error converting the call result: %s"), err.msg);
  }

end:
  api_free_array(args);
  if (handler.arena_return) {
    arena_mem_free(arena_finish(&res_arena));
  } else {
    api_free_object(result);
  }
  api_clear_error(&err);
}

/// "abs(expr)" function
static void f_abs(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type == VAR_FLOAT) {
    float_op_wrapper(argvars, rettv, (EvalFuncData){ .float_func = &fabs });
  } else {
    bool error = false;

    varnumber_T n = tv_get_number_chk(&argvars[0], &error);
    if (error) {
      rettv->vval.v_number = -1;
    } else if (n > 0) {
      rettv->vval.v_number = n;
    } else {
      rettv->vval.v_number = -n;
    }
  }
}

/// "add(list, item)" function
static void f_add(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = 1;  // Default: failed.
  if (argvars[0].v_type == VAR_LIST) {
    list_T *const l = argvars[0].vval.v_list;
    if (!var_check_lock(tv_list_locked(l), N_("add() argument"),
                        TV_TRANSLATE)) {
      tv_list_append_tv(l, &argvars[1]);
      tv_copy(&argvars[0], rettv);
    }
  } else if (argvars[0].v_type == VAR_BLOB) {
    blob_T *const b = argvars[0].vval.v_blob;
    if (b != NULL
        && !var_check_lock(b->bv_lock, N_("add() argument"), TV_TRANSLATE)) {
      bool error = false;
      const varnumber_T n = tv_get_number_chk(&argvars[1], &error);

      if (!error) {
        ga_append(&b->bv_ga, (char)n);
        tv_copy(&argvars[0], rettv);
      }
    }
  } else {
    emsg(_(e_listblobreq));
  }
}

/// "and(expr, expr)" function
static void f_and(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = tv_get_number_chk(&argvars[0], NULL)
                         & tv_get_number_chk(&argvars[1], NULL);
}

/// "api_info()" function
static void f_api_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  Dictionary metadata = api_metadata();
  (void)object_to_vim(DICTIONARY_OBJ(metadata), rettv, NULL);
}

/// "atan2()" function
static void f_atan2(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  float_T fx;
  float_T fy;

  rettv->v_type = VAR_FLOAT;
  if (tv_get_float_chk(argvars, &fx) && tv_get_float_chk(&argvars[1], &fy)) {
    rettv->vval.v_float = atan2(fx, fy);
  } else {
    rettv->vval.v_float = 0.0;
  }
}

/// "browse(save, title, initdir, default)" function
static void f_browse(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_string = NULL;
  rettv->v_type = VAR_STRING;
}

/// "browsedir(title, initdir)" function
static void f_browsedir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  f_browse(argvars, rettv, fptr);
}

/// Get buffer by number or pattern.
buf_T *tv_get_buf(typval_T *tv, int curtab_only)
{
  if (tv->v_type == VAR_NUMBER) {
    return buflist_findnr((int)tv->vval.v_number);
  }
  if (tv->v_type != VAR_STRING) {
    return NULL;
  }

  char *name = tv->vval.v_string;

  if (name == NULL || *name == NUL) {
    return curbuf;
  }
  if (name[0] == '$' && name[1] == NUL) {
    return lastbuf;
  }

  // Ignore 'magic' and 'cpoptions' here to make scripts portable
  int save_magic = p_magic;
  p_magic = true;
  char *save_cpo = p_cpo;
  p_cpo = empty_option;

  buf_T *buf = buflist_findnr(buflist_findpat(name, name + strlen(name),
                                              true, false, curtab_only));

  p_magic = save_magic;
  p_cpo = save_cpo;

  // If not found, try expanding the name, like done for bufexists().
  if (buf == NULL) {
    buf = find_buffer(tv);
  }

  return buf;
}

/// Like tv_get_buf() but give an error message if the type is wrong.
buf_T *tv_get_buf_from_arg(typval_T *const tv) FUNC_ATTR_NONNULL_ALL
{
  if (!tv_check_str_or_nr(tv)) {
    return NULL;
  }
  emsg_off++;
  buf_T *const buf = tv_get_buf(tv, false);
  emsg_off--;
  return buf;
}

/// Get the buffer from "arg" and give an error and return NULL if it is not
/// valid.
buf_T *get_buf_arg(typval_T *arg)
{
  emsg_off++;
  buf_T *buf = tv_get_buf(arg, false);
  emsg_off--;
  if (buf == NULL) {
    semsg(_("E158: Invalid buffer name: %s"), tv_get_string(arg));
  }
  return buf;
}

/// "byte2line(byte)" function
static void f_byte2line(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  long boff = tv_get_number(&argvars[0]) - 1;
  if (boff < 0) {
    rettv->vval.v_number = -1;
  } else {
    rettv->vval.v_number = (varnumber_T)ml_find_line_or_offset(curbuf, 0,
                                                               &boff, false);
  }
}

static void byteidx(typval_T *argvars, typval_T *rettv, int comp)
{
  const char *const str = tv_get_string_chk(&argvars[0]);
  varnumber_T idx = tv_get_number_chk(&argvars[1], NULL);
  rettv->vval.v_number = -1;
  if (str == NULL || idx < 0) {
    return;
  }

  const char *t = str;
  for (; idx > 0; idx--) {
    if (*t == NUL) {  // EOL reached.
      return;
    }
    if (comp) {
      t += utf_ptr2len(t);
    } else {
      t += utfc_ptr2len(t);
    }
  }
  rettv->vval.v_number = (varnumber_T)(t - str);
}

/// "byteidx()" function
static void f_byteidx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  byteidx(argvars, rettv, false);
}

/// "byteidxcomp()" function
static void f_byteidxcomp(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  byteidx(argvars, rettv, true);
}

/// "call(func, arglist [, dict])" function
static void f_call(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[1].v_type != VAR_LIST) {
    emsg(_(e_listreq));
    return;
  }
  if (argvars[1].vval.v_list == NULL) {
    return;
  }

  bool owned = false;
  char_u *func;
  partial_T *partial = NULL;
  if (argvars[0].v_type == VAR_FUNC) {
    func = (char_u *)argvars[0].vval.v_string;
  } else if (argvars[0].v_type == VAR_PARTIAL) {
    partial = argvars[0].vval.v_partial;
    func = (char_u *)partial_name(partial);
  } else if (nlua_is_table_from_lua(&argvars[0])) {
    // TODO(tjdevries): UnifiedCallback
    func = nlua_register_table_as_callable(&argvars[0]);
    owned = true;
  } else {
    func = (char_u *)tv_get_string(&argvars[0]);
  }

  if (*func == NUL) {
    return;             // type error or empty name
  }

  dict_T *selfdict = NULL;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    if (argvars[2].v_type != VAR_DICT) {
      emsg(_(e_dictreq));
      if (owned) {
        func_unref(func);
      }
      return;
    }
    selfdict = argvars[2].vval.v_dict;
  }

  func_call(func, &argvars[1], partial, selfdict, rettv);
  if (owned) {
    func_unref(func);
  }
}

/// "changenr()" function
static void f_changenr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = curbuf->b_u_seq_cur;
}

/// "chanclose(id[, stream])" function
static void f_chanclose(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER || (argvars[1].v_type != VAR_STRING
                                          && argvars[1].v_type != VAR_UNKNOWN)) {
    emsg(_(e_invarg));
    return;
  }

  ChannelPart part = kChannelPartAll;
  if (argvars[1].v_type == VAR_STRING) {
    char *stream = argvars[1].vval.v_string;
    if (!strcmp(stream, "stdin")) {
      part = kChannelPartStdin;
    } else if (!strcmp(stream, "stdout")) {
      part = kChannelPartStdout;
    } else if (!strcmp(stream, "stderr")) {
      part = kChannelPartStderr;
    } else if (!strcmp(stream, "rpc")) {
      part = kChannelPartRpc;
    } else {
      semsg(_("Invalid channel stream \"%s\""), stream);
      return;
    }
  }
  const char *error;
  rettv->vval.v_number = channel_close((uint64_t)argvars[0].vval.v_number, part, &error);
  if (!rettv->vval.v_number) {
    emsg(error);
  }
}

/// "chansend(id, data)" function
static void f_chansend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type == VAR_UNKNOWN) {
    // First argument is the channel id and second is the data to write
    emsg(_(e_invarg));
    return;
  }

  ptrdiff_t input_len = 0;
  char *input = NULL;
  uint64_t id = (uint64_t)argvars[0].vval.v_number;
#ifdef UNIX
  bool crlf = false;
#else
  Channel *chan = find_channel(id);
  bool crlf = (chan != NULL && chan->term) ? true: false;
#endif

  if (argvars[1].v_type == VAR_BLOB) {
    const blob_T *const b = argvars[1].vval.v_blob;
    input_len = tv_blob_len(b);
    if (input_len > 0) {
      input = xmemdup(b->bv_ga.ga_data, (size_t)input_len);
    }
  } else {
    input = save_tv_as_string(&argvars[1], &input_len, false, crlf);
  }

  if (!input) {
    // Either the error has been handled by save_tv_as_string(),
    // or there is no input to send.
    return;
  }
  const char *error = NULL;
  rettv->vval.v_number = (varnumber_T)channel_send(id, input, (size_t)input_len, true, &error);
  if (error) {
    emsg(error);
  }
}

/// "char2nr(string)" function
static void f_char2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[1].v_type != VAR_UNKNOWN) {
    if (!tv_check_num(&argvars[1])) {
      return;
    }
  }

  rettv->vval.v_number = utf_ptr2char(tv_get_string(&argvars[0]));
}

/// Get the current cursor column and store it in 'rettv'.
///
/// @return  the character index of the column if 'charcol' is true,
///          otherwise the byte index of the column.
static void get_col(typval_T *argvars, typval_T *rettv, bool charcol)
{
  if (tv_check_for_string_or_list_arg(argvars, 0) == FAIL
      || tv_check_for_opt_number_arg(argvars, 1) == FAIL) {
    return;
  }

  switchwin_T switchwin;
  bool winchanged = false;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    // use the window specified in the second argument
    tabpage_T *tp;
    win_T *wp = win_id2wp_tp((int)tv_get_number(&argvars[1]), &tp);
    if (wp == NULL || tp == NULL) {
      return;
    }

    if (switch_win_noblock(&switchwin, wp, tp, true) != OK) {
      return;
    }

    check_cursor();
    winchanged = true;
  }

  colnr_T col = 0;
  int fnum = curbuf->b_fnum;
  pos_T *fp = var2fpos(&argvars[0], false, &fnum, charcol);
  if (fp != NULL && fnum == curbuf->b_fnum) {
    if (fp->col == MAXCOL) {
      // '> can be MAXCOL, get the length of the line then
      if (fp->lnum <= curbuf->b_ml.ml_line_count) {
        col = (colnr_T)strlen(ml_get(fp->lnum)) + 1;
      } else {
        col = MAXCOL;
      }
    } else {
      col = fp->col + 1;
      // col(".") when the cursor is on the NUL at the end of the line
      // because of "coladd" can be seen as an extra column.
      if (virtual_active() && fp == &curwin->w_cursor) {
        char *p = get_cursor_pos_ptr();
        if (curwin->w_cursor.coladd >=
            (colnr_T)win_chartabsize(curwin, p,
                                     curwin->w_virtcol - curwin->w_cursor.coladd)) {
          int l;
          if (*p != NUL && p[(l = utfc_ptr2len(p))] == NUL) {
            col += l;
          }
        }
      }
    }
  }
  rettv->vval.v_number = col;

  if (winchanged) {
    restore_win_noblock(&switchwin, true);
  }
}

/// "charcol()" function
static void f_charcol(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_col(argvars, rettv, true);
}

/// "charidx()" function
static void f_charidx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = -1;

  if (argvars[0].v_type != VAR_STRING
      || argvars[1].v_type != VAR_NUMBER
      || (argvars[2].v_type != VAR_UNKNOWN
          && argvars[2].v_type != VAR_NUMBER
          && argvars[2].v_type != VAR_BOOL)) {
    emsg(_(e_invarg));
    return;
  }

  const char *str = tv_get_string_chk(&argvars[0]);
  varnumber_T idx = tv_get_number_chk(&argvars[1], NULL);
  if (str == NULL || idx < 0) {
    return;
  }
  int countcc = 0;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    countcc = (int)tv_get_number(&argvars[2]);
  }
  if (countcc < 0 || countcc > 1) {
    semsg(_(e_using_number_as_bool_nr), countcc);
    return;
  }

  int (*ptr2len)(const char *);
  if (countcc) {
    ptr2len = utf_ptr2len;
  } else {
    ptr2len = utfc_ptr2len;
  }

  const char *p;
  int len;
  for (p = str, len = 0; p <= str + idx; len++) {
    if (*p == NUL) {
      return;
    }
    p += ptr2len(p);
  }

  rettv->vval.v_number = len > 0 ? len - 1 : 0;
}

/// "chdir(dir)" function
static void f_chdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  if (argvars[0].v_type != VAR_STRING) {
    // Returning an empty string means it failed.
    // No error message, for historic reasons.
    return;
  }

  // Return the current directory
  char *cwd = xmalloc(MAXPATHL);
  if (os_dirname((char_u *)cwd, MAXPATHL) != FAIL) {
#ifdef BACKSLASH_IN_FILENAME
    slash_adjust(cwd);
#endif
    rettv->vval.v_string = xstrdup(cwd);
  }
  xfree(cwd);

  CdScope scope = kCdScopeGlobal;
  if (curwin->w_localdir != NULL) {
    scope = kCdScopeWindow;
  } else if (curtab->tp_localdir != NULL) {
    scope = kCdScopeTabpage;
  }

  if (!changedir_func(argvars[0].vval.v_string, scope)) {
    // Directory change failed
    XFREE_CLEAR(rettv->vval.v_string);
  }
}

/// "cindent(lnum)" function
static void f_cindent(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  pos_T pos = curwin->w_cursor;
  linenr_T lnum = tv_get_lnum(argvars);
  if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count) {
    curwin->w_cursor.lnum = lnum;
    rettv->vval.v_number = get_c_indent();
    curwin->w_cursor = pos;
  } else {
    rettv->vval.v_number = -1;
  }
}

win_T *get_optional_window(typval_T *argvars, int idx)
{
  win_T *win = curwin;

  if (argvars[idx].v_type != VAR_UNKNOWN) {
    win = find_win_by_nr_or_id(&argvars[idx]);
    if (win == NULL) {
      emsg(_(e_invalwindow));
      return NULL;
    }
  }
  return win;
}

/// "col(string)" function
static void f_col(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_col(argvars, rettv, false);
}

/// "confirm(message, buttons[, default [, type]])" function
static void f_confirm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf[NUMBUFLEN];
  char buf2[NUMBUFLEN];
  const char *buttons = NULL;
  int def = 1;
  int type = VIM_GENERIC;
  bool error = false;

  const char *message = tv_get_string_chk(&argvars[0]);
  if (message == NULL) {
    error = true;
  }
  if (argvars[1].v_type != VAR_UNKNOWN) {
    buttons = tv_get_string_buf_chk(&argvars[1], buf);
    if (buttons == NULL) {
      error = true;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      def = (int)tv_get_number_chk(&argvars[2], &error);
      if (argvars[3].v_type != VAR_UNKNOWN) {
        const char *typestr = tv_get_string_buf_chk(&argvars[3], buf2);
        if (typestr == NULL) {
          error = true;
        } else {
          switch (TOUPPER_ASC(*typestr)) {
          case 'E':
            type = VIM_ERROR; break;
          case 'Q':
            type = VIM_QUESTION; break;
          case 'I':
            type = VIM_INFO; break;
          case 'W':
            type = VIM_WARNING; break;
          case 'G':
            type = VIM_GENERIC; break;
          }
        }
      }
    }
  }

  if (buttons == NULL || *buttons == NUL) {
    buttons = _("&Ok");
  }

  if (!error) {
    rettv->vval.v_number = do_dialog(type, NULL, (char *)message, (char *)buttons, def, NULL,
                                     false);
  }
}

/// "copy()" function
static void f_copy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  var_item_copy(NULL, &argvars[0], rettv, false, 0);
}

/// "count()" function
static void f_count(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  long n = 0;
  int ic = 0;
  bool error = false;

  if (argvars[2].v_type != VAR_UNKNOWN) {
    ic = (int)tv_get_number_chk(&argvars[2], &error);
  }

  if (argvars[0].v_type == VAR_STRING) {
    const char *expr = tv_get_string_chk(&argvars[1]);
    const char_u *p = (char_u *)argvars[0].vval.v_string;

    if (!error && expr != NULL && *expr != NUL && p != NULL) {
      if (ic) {
        const size_t len = strlen(expr);

        while (*p != NUL) {
          if (mb_strnicmp((char *)p, (char *)expr, len) == 0) {
            n++;
            p += len;
          } else {
            MB_PTR_ADV(p);
          }
        }
      } else {
        char_u *next;
        while ((next = (char_u *)strstr((char *)p, (char *)expr)) != NULL) {
          n++;
          p = next + strlen(expr);
        }
      }
    }
  } else if (argvars[0].v_type == VAR_LIST) {
    list_T *l = argvars[0].vval.v_list;

    if (l != NULL) {
      listitem_T *li = tv_list_first(l);
      if (argvars[2].v_type != VAR_UNKNOWN) {
        if (argvars[3].v_type != VAR_UNKNOWN) {
          long idx = tv_get_number_chk(&argvars[3], &error);
          if (!error) {
            li = tv_list_find(l, (int)idx);
            if (li == NULL) {
              semsg(_(e_listidx), (int64_t)idx);
            }
          }
        }
        if (error) {
          li = NULL;
        }
      }

      for (; li != NULL; li = TV_LIST_ITEM_NEXT(l, li)) {
        if (tv_equal(TV_LIST_ITEM_TV(li), &argvars[1], ic, false)) {
          n++;
        }
      }
    }
  } else if (argvars[0].v_type == VAR_DICT) {
    dict_T *d = argvars[0].vval.v_dict;

    if (d != NULL) {
      if (argvars[2].v_type != VAR_UNKNOWN) {
        if (argvars[3].v_type != VAR_UNKNOWN) {
          emsg(_(e_invarg));
        }
      }

      int todo = error ? 0 : (int)d->dv_hashtab.ht_used;
      for (hashitem_T *hi = d->dv_hashtab.ht_array; todo > 0; hi++) {
        if (!HASHITEM_EMPTY(hi)) {
          todo--;
          if (tv_equal(&TV_DICT_HI2DI(hi)->di_tv, &argvars[1], ic, false)) {
            n++;
          }
        }
      }
    }
  } else {
    semsg(_(e_listdictarg), "count()");
  }
  rettv->vval.v_number = n;
}

/// "ctxget([{index}])" function
static void f_ctxget(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  size_t index = 0;
  if (argvars[0].v_type == VAR_NUMBER) {
    index = (size_t)argvars[0].vval.v_number;
  } else if (argvars[0].v_type != VAR_UNKNOWN) {
    semsg(_(e_invarg2), "expected nothing or a Number as an argument");
    return;
  }

  Context *ctx = ctx_get(index);
  if (ctx == NULL) {
    semsg(_(e_invargNval), "index", "out of bounds");
    return;
  }

  Dictionary ctx_dict = ctx_to_dict(ctx);
  Error err = ERROR_INIT;
  object_to_vim(DICTIONARY_OBJ(ctx_dict), rettv, &err);
  api_free_dictionary(ctx_dict);
  api_clear_error(&err);
}

/// "ctxpop()" function
static void f_ctxpop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (!ctx_restore(NULL, kCtxAll)) {
    emsg(_("Context stack is empty"));
  }
}

/// "ctxpush([{types}])" function
static void f_ctxpush(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int types = kCtxAll;
  if (argvars[0].v_type == VAR_LIST) {
    types = 0;
    TV_LIST_ITER(argvars[0].vval.v_list, li, {
      typval_T *tv_li = TV_LIST_ITEM_TV(li);
      if (tv_li->v_type == VAR_STRING) {
        if (strequal((char *)tv_li->vval.v_string, "regs")) {
          types |= kCtxRegs;
        } else if (strequal((char *)tv_li->vval.v_string, "jumps")) {
          types |= kCtxJumps;
        } else if (strequal((char *)tv_li->vval.v_string, "bufs")) {
          types |= kCtxBufs;
        } else if (strequal((char *)tv_li->vval.v_string, "gvars")) {
          types |= kCtxGVars;
        } else if (strequal((char *)tv_li->vval.v_string, "sfuncs")) {
          types |= kCtxSFuncs;
        } else if (strequal((char *)tv_li->vval.v_string, "funcs")) {
          types |= kCtxFuncs;
        }
      }
    });
  } else if (argvars[0].v_type != VAR_UNKNOWN) {
    semsg(_(e_invarg2), "expected nothing or a List as an argument");
    return;
  }
  ctx_save(NULL, types);
}

/// "ctxset({context}[, {index}])" function
static void f_ctxset(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_DICT) {
    semsg(_(e_invarg2), "expected dictionary as first argument");
    return;
  }

  size_t index = 0;
  if (argvars[1].v_type == VAR_NUMBER) {
    index = (size_t)argvars[1].vval.v_number;
  } else if (argvars[1].v_type != VAR_UNKNOWN) {
    semsg(_(e_invarg2), "expected nothing or a Number as second argument");
    return;
  }

  Context *ctx = ctx_get(index);
  if (ctx == NULL) {
    semsg(_(e_invargNval), "index", "out of bounds");
    return;
  }

  int save_did_emsg = did_emsg;
  did_emsg = false;

  Dictionary dict = vim_to_object(&argvars[0]).data.dictionary;
  Context tmp = CONTEXT_INIT;
  ctx_from_dict(dict, &tmp);

  if (did_emsg) {
    ctx_free(&tmp);
  } else {
    ctx_free(ctx);
    *ctx = tmp;
  }

  api_free_dictionary(dict);
  did_emsg = save_did_emsg;
}

/// "ctxsize()" function
static void f_ctxsize(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = (varnumber_T)ctx_size();
}

/// Set the cursor position.
/// If 'charcol' is true, then use the column number as a character offset.
/// Otherwise use the column number as a byte offset.
static void set_cursorpos(typval_T *argvars, typval_T *rettv, bool charcol)
{
  long lnum, col;
  long coladd = 0;
  bool set_curswant = true;

  rettv->vval.v_number = -1;
  if (argvars[0].v_type == VAR_LIST) {
    pos_T pos;
    colnr_T curswant = -1;

    if (list2fpos(argvars, &pos, NULL, &curswant, charcol) == FAIL) {
      emsg(_(e_invarg));
      return;
    }

    lnum = pos.lnum;
    col = pos.col;
    coladd = pos.coladd;
    if (curswant >= 0) {
      curwin->w_curswant = curswant - 1;
      set_curswant = false;
    }
  } else if ((argvars[0].v_type == VAR_NUMBER || argvars[0].v_type == VAR_STRING)
             && (argvars[1].v_type == VAR_NUMBER || argvars[1].v_type == VAR_STRING)) {
    lnum = tv_get_lnum(argvars);
    if (lnum < 0) {
      semsg(_(e_invarg2), tv_get_string(&argvars[0]));
    } else if (lnum == 0) {
      lnum = curwin->w_cursor.lnum;
    }
    col = (long)tv_get_number_chk(&argvars[1], NULL);
    if (charcol) {
      col = buf_charidx_to_byteidx(curbuf, (linenr_T)lnum, (int)col) + 1;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      coladd = (long)tv_get_number_chk(&argvars[2], NULL);
    }
  } else {
    emsg(_(e_invarg));
    return;
  }
  if (lnum < 0 || col < 0 || coladd < 0) {
    return;  // type error; errmsg already given
  }
  if (lnum > 0) {
    curwin->w_cursor.lnum = (linenr_T)lnum;
  }
  if (col > 0) {
    curwin->w_cursor.col = (colnr_T)col - 1;
  }
  curwin->w_cursor.coladd = (colnr_T)coladd;

  // Make sure the cursor is in a valid position.
  check_cursor();
  // Correct cursor for multi-byte character.
  mb_adjust_cursor();

  curwin->w_set_curswant = set_curswant;
  rettv->vval.v_number = 0;
}

/// "cursor(lnum, col)" function, or
/// "cursor(list)"
///
/// Moves the cursor to the specified line and column.
///
/// @return  0 when the position could be set, -1 otherwise.
static void f_cursor(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  set_cursorpos(argvars, rettv, false);
}

/// "debugbreak()" function
static void f_debugbreak(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = FAIL;
  int pid = (int)tv_get_number(&argvars[0]);
  if (pid == 0) {
    emsg(_(e_invarg));
    return;
  }

#ifdef MSWIN
  HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
  if (hProcess == NULL) {
    return;
  }

  DebugBreakProcess(hProcess);
  CloseHandle(hProcess);
  rettv->vval.v_number = OK;
#else
  uv_kill(pid, SIGINT);
#endif
}

/// "deepcopy()" function
static void f_deepcopy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int noref = 0;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    noref = (int)tv_get_bool_chk(&argvars[1], NULL);
  }
  if (noref < 0 || noref > 1) {
    semsg(_(e_using_number_as_bool_nr), noref);
  } else {
    var_item_copy(NULL, &argvars[0], rettv, true, (noref == 0
                                                   ? get_copyID()
                                                   : 0));
  }
}

/// "delete()" function
static void f_delete(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = -1;
  if (check_secure()) {
    return;
  }

  const char *const name = tv_get_string(&argvars[0]);
  if (*name == NUL) {
    emsg(_(e_invarg));
    return;
  }

  char nbuf[NUMBUFLEN];
  const char *flags;
  if (argvars[1].v_type != VAR_UNKNOWN) {
    flags = tv_get_string_buf(&argvars[1], nbuf);
  } else {
    flags = "";
  }

  if (*flags == NUL) {
    // delete a file
    rettv->vval.v_number = os_remove(name) == 0 ? 0 : -1;
  } else if (strcmp(flags, "d") == 0) {
    // delete an empty directory
    rettv->vval.v_number = os_rmdir(name) == 0 ? 0 : -1;
  } else if (strcmp(flags, "rf") == 0) {
    // delete a directory recursively
    rettv->vval.v_number = delete_recursive(name);
  } else {
    semsg(_(e_invexpr2), flags);
  }
}

/// dictwatcheradd(dict, key, funcref) function
static void f_dictwatcheradd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_DICT) {
    semsg(_(e_invarg2), "dict");
    return;
  } else if (argvars[0].vval.v_dict == NULL) {
    const char *const arg_errmsg = _("dictwatcheradd() argument");
    const size_t arg_errmsg_len = strlen(arg_errmsg);
    semsg(_(e_readonlyvar), (int)arg_errmsg_len, arg_errmsg);
    return;
  }

  if (argvars[1].v_type != VAR_STRING && argvars[1].v_type != VAR_NUMBER) {
    semsg(_(e_invarg2), "key");
    return;
  }

  const char *const key_pattern = tv_get_string_chk(argvars + 1);
  if (key_pattern == NULL) {
    return;
  }
  const size_t key_pattern_len = strlen(key_pattern);

  Callback callback;
  if (!callback_from_typval(&callback, &argvars[2])) {
    semsg(_(e_invarg2), "funcref");
    return;
  }

  tv_dict_watcher_add(argvars[0].vval.v_dict, key_pattern, key_pattern_len,
                      callback);
}

/// dictwatcherdel(dict, key, funcref) function
static void f_dictwatcherdel(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_DICT) {
    semsg(_(e_invarg2), "dict");
    return;
  }

  if (argvars[2].v_type != VAR_FUNC && argvars[2].v_type != VAR_STRING) {
    semsg(_(e_invarg2), "funcref");
    return;
  }

  const char *const key_pattern = tv_get_string_chk(argvars + 1);
  if (key_pattern == NULL) {
    return;
  }

  Callback callback;
  if (!callback_from_typval(&callback, &argvars[2])) {
    return;
  }

  if (!tv_dict_watcher_remove(argvars[0].vval.v_dict, key_pattern,
                              strlen(key_pattern), callback)) {
    emsg("Couldn't find a watcher matching key and callback");
  }

  callback_free(&callback);
}

/// "did_filetype()" function
static void f_did_filetype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = did_filetype;
}

/// "diff_filler()" function
static void f_diff_filler(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = MAX(0, diff_check(curwin, tv_get_lnum(argvars)));
}

/// "diff_hlID()" function
static void f_diff_hlID(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  linenr_T lnum = tv_get_lnum(argvars);
  static linenr_T prev_lnum = 0;
  static varnumber_T changedtick = 0;
  static int fnum = 0;
  static int change_start = 0;
  static int change_end = 0;
  static hlf_T hlID = (hlf_T)0;

  if (lnum < 0) {       // ignore type error in {lnum} arg
    lnum = 0;
  }
  if (lnum != prev_lnum
      || changedtick != buf_get_changedtick(curbuf)
      || fnum != curbuf->b_fnum) {
    // New line, buffer, change: need to get the values.
    int linestatus = 0;
    int filler_lines = diff_check_with_linestatus(curwin, lnum, &linestatus);
    if (filler_lines < 0 || linestatus < 0) {
      if (filler_lines == -1 || linestatus == -1) {
        change_start = MAXCOL;
        change_end = -1;
        if (diff_find_change(curwin, lnum, &change_start, &change_end)) {
          hlID = HLF_ADD;               // added line
        } else {
          hlID = HLF_CHD;               // changed line
        }
      } else {
        hlID = HLF_ADD;         // added line
      }
    } else {
      hlID = (hlf_T)0;
    }
    prev_lnum = lnum;
    changedtick = buf_get_changedtick(curbuf);
    fnum = curbuf->b_fnum;
  }

  if (hlID == HLF_CHD || hlID == HLF_TXD) {
    int col = (int)tv_get_number(&argvars[1]) - 1;  // Ignore type error in {col}.
    if (col >= change_start && col <= change_end) {
      hlID = HLF_TXD;  // Changed text.
    } else {
      hlID = HLF_CHD;  // Changed line.
    }
  }
  rettv->vval.v_number = hlID == (hlf_T)0 ? 0 : (int)(hlID + 1);
}

/// "empty({expr})" function
static void f_empty(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  bool n = true;

  switch (argvars[0].v_type) {
  case VAR_STRING:
  case VAR_FUNC:
    n = argvars[0].vval.v_string == NULL
        || *argvars[0].vval.v_string == NUL;
    break;
  case VAR_PARTIAL:
    n = false;
    break;
  case VAR_NUMBER:
    n = argvars[0].vval.v_number == 0;
    break;
  case VAR_FLOAT:
    n = argvars[0].vval.v_float == 0.0;
    break;
  case VAR_LIST:
    n = (tv_list_len(argvars[0].vval.v_list) == 0);
    break;
  case VAR_DICT:
    n = (tv_dict_len(argvars[0].vval.v_dict) == 0);
    break;
  case VAR_BOOL:
    switch (argvars[0].vval.v_bool) {
    case kBoolVarTrue:
      n = false;
      break;
    case kBoolVarFalse:
      n = true;
      break;
    }
    break;
  case VAR_SPECIAL:
    n = argvars[0].vval.v_special == kSpecialVarNull;
    break;
  case VAR_BLOB:
    n = (tv_blob_len(argvars[0].vval.v_blob) == 0);
    break;
  case VAR_UNKNOWN:
    internal_error("f_empty(UNKNOWN)");
    break;
  }

  rettv->vval.v_number = n;
}

/// "environ()" function
static void f_environ(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);

  size_t env_size = os_get_fullenv_size();
  char **env = xmalloc(sizeof(*env) * (env_size + 1));
  env[env_size] = NULL;

  os_copy_fullenv(env, env_size);

  for (ssize_t i = (ssize_t)env_size - 1; i >= 0; i--) {
    const char *str = env[i];
    const char * const end = strchr(str + (str[0] == '=' ? 1 : 0),
                                    '=');
    assert(end != NULL);
    ptrdiff_t len = end - str;
    assert(len > 0);
    const char *value = str + len + 1;

    char c = env[i][len];
    env[i][len] = NUL;

#ifdef MSWIN
    // Upper-case all the keys for Windows so we can detect duplicates
    char *const key = strcase_save(str, true);
#else
    char *const key = xstrdup(str);
#endif

    env[i][len] = c;

    if (tv_dict_find(rettv->vval.v_dict, key, len) != NULL) {
      // Since we're traversing from the end of the env block to the front, any
      // duplicate names encountered should be ignored.  This preserves the
      // semantics of env vars defined later in the env block taking precedence.
      xfree(key);
      continue;
    }
    tv_dict_add_str(rettv->vval.v_dict, key, (size_t)len, value);
    xfree(key);
  }
  os_free_fullenv(env);
}

/// "escape({string}, {chars})" function
static void f_escape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf[NUMBUFLEN];

  rettv->vval.v_string = (char *)vim_strsave_escaped((const char_u *)tv_get_string(&argvars[0]),
                                                     (const char_u *)tv_get_string_buf(&argvars[1],
                                                                                       buf));
  rettv->v_type = VAR_STRING;
}

/// "getenv()" function
static void f_getenv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char_u *p = (char_u *)vim_getenv(tv_get_string(&argvars[0]));

  if (p == NULL) {
    rettv->v_type = VAR_SPECIAL;
    rettv->vval.v_special = kSpecialVarNull;
    return;
  }
  rettv->vval.v_string = (char *)p;
  rettv->v_type = VAR_STRING;
}

/// "eval()" function
static void f_eval(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *s = tv_get_string_chk(&argvars[0]);
  if (s != NULL) {
    s = (const char *)skipwhite(s);
  }

  const char *const expr_start = s;
  if (s == NULL || eval1((char **)&s, rettv, true) == FAIL) {
    if (expr_start != NULL && !aborting()) {
      semsg(_(e_invexpr2), expr_start);
    }
    need_clr_eos = false;
    rettv->v_type = VAR_NUMBER;
    rettv->vval.v_number = 0;
  } else if (*s != NUL) {
    semsg(_(e_trailing_arg), s);
  }
}

/// "eventhandler()" function
static void f_eventhandler(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = vgetc_busy;
}

/// "executable()" function
static void f_executable(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (tv_check_for_string_arg(argvars, 0) == FAIL) {
    return;
  }

  // Check in $PATH and also check directly if there is a directory name
  rettv->vval.v_number = os_can_exe(tv_get_string(&argvars[0]), NULL, true);
}

typedef struct {
  const list_T *const l;
  const listitem_T *li;
} GetListLineCookie;

static char *get_list_line(int c, void *cookie, int indent, bool do_concat)
{
  GetListLineCookie *const p = (GetListLineCookie *)cookie;

  const listitem_T *const item = p->li;
  if (item == NULL) {
    return NULL;
  }
  char buf[NUMBUFLEN];
  const char *const s = tv_get_string_buf_chk(TV_LIST_ITEM_TV(item), buf);
  p->li = TV_LIST_ITEM_NEXT(p->l, item);
  return s == NULL ? NULL : xstrdup(s);
}

void execute_common(typval_T *argvars, typval_T *rettv, int arg_off)
{
  const int save_msg_silent = msg_silent;
  const int save_emsg_silent = emsg_silent;
  const bool save_emsg_noredir = emsg_noredir;
  const bool save_redir_off = redir_off;
  garray_T *const save_capture_ga = capture_ga;
  const int save_msg_col = msg_col;
  bool echo_output = false;

  if (check_secure()) {
    return;
  }

  if (argvars[arg_off + 1].v_type != VAR_UNKNOWN) {
    char buf[NUMBUFLEN];
    const char *const s = tv_get_string_buf_chk(&argvars[arg_off + 1], buf);

    if (s == NULL) {
      return;
    }
    if (*s == NUL) {
      echo_output = true;
    }
    if (strncmp(s, "silent", 6) == 0) {
      msg_silent++;
    }
    if (strcmp(s, "silent!") == 0) {
      emsg_silent = true;
      emsg_noredir = true;
    }
  } else {
    msg_silent++;
  }

  garray_T capture_local;
  ga_init(&capture_local, (int)sizeof(char), 80);
  capture_ga = &capture_local;
  redir_off = false;
  if (!echo_output) {
    msg_col = 0;  // prevent leading spaces
  }

  if (argvars[arg_off].v_type != VAR_LIST) {
    do_cmdline_cmd(tv_get_string(&argvars[arg_off]));
  } else if (argvars[arg_off].vval.v_list != NULL) {
    list_T *const list = argvars[arg_off].vval.v_list;
    tv_list_ref(list);
    GetListLineCookie cookie = {
      .l = list,
      .li = tv_list_first(list),
    };
    do_cmdline(NULL, get_list_line, (void *)&cookie,
               DOCMD_NOWAIT|DOCMD_VERBOSE|DOCMD_REPEAT|DOCMD_KEYTYPED);
    tv_list_unref(list);
  }
  msg_silent = save_msg_silent;
  emsg_silent = save_emsg_silent;
  emsg_noredir = save_emsg_noredir;
  redir_off = save_redir_off;
  // "silent reg" or "silent echo x" leaves msg_col somewhere in the line.
  if (echo_output) {
    // When not working silently: put it in column zero.  A following
    // "echon" will overwrite the message, unavoidably.
    msg_col = 0;
  } else {
    // When working silently: Put it back where it was, since nothing
    // should have been written.
    msg_col = save_msg_col;
  }

  ga_append(capture_ga, NUL);
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = capture_ga->ga_data;

  capture_ga = save_capture_ga;
}

/// "execute(command)" function
static void f_execute(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  execute_common(argvars, rettv, 0);
}

/// "exepath()" function
static void f_exepath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (tv_check_for_nonempty_string_arg(argvars, 0) == FAIL) {
    return;
  }

  char *path = NULL;

  (void)os_can_exe(tv_get_string(&argvars[0]), &path, true);

#ifdef BACKSLASH_IN_FILENAME
  if (path != NULL) {
    slash_adjust((char_u *)path);
  }
#endif

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = path;
}

/// "exists()" function
static void f_exists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int n = false;

  const char *p = tv_get_string(&argvars[0]);
  if (*p == '$') {  // Environment variable.
    // First try "normal" environment variables (fast).
    if (os_env_exists(p + 1)) {
      n = true;
    } else {
      // Try expanding things like $VIM and ${HOME}.
      char *const exp = expand_env_save((char *)p);
      if (exp != NULL && *exp != '$') {
        n = true;
      }
      xfree(exp);
    }
  } else if (*p == '&' || *p == '+') {  // Option.
    n = (get_option_tv(&p, NULL, true) == OK);
    if (*skipwhite(p) != NUL) {
      n = false;  // Trailing garbage.
    }
  } else if (*p == '*') {  // Internal or user defined function.
    n = function_exists(p + 1, false);
  } else if (*p == ':') {
    n = cmd_exists(p + 1);
  } else if (*p == '#') {
    if (p[1] == '#') {
      n = autocmd_supported(p + 2);
    } else {
      n = au_exists(p + 1);
    }
  } else {  // Internal variable.
    n = var_exists(p);
  }

  rettv->vval.v_number = n;
}

/// "expand()" function
static void f_expand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int options = WILD_SILENT|WILD_USE_NL|WILD_LIST_NOTFOUND;
  bool error = false;
#ifdef BACKSLASH_IN_FILENAME
  char_u *p_csl_save = p_csl;

  // avoid using 'completeslash' here
  p_csl = empty_option;
#endif

  rettv->v_type = VAR_STRING;
  if (argvars[1].v_type != VAR_UNKNOWN
      && argvars[2].v_type != VAR_UNKNOWN
      && tv_get_number_chk(&argvars[2], &error)
      && !error) {
    tv_list_set_ret(rettv, NULL);
  }

  const char *s = tv_get_string(&argvars[0]);
  if (*s == '%' || *s == '#' || *s == '<') {
    if (p_verbose == 0) {
      emsg_off++;
    }
    size_t len;
    char *errormsg = NULL;
    char_u *result = eval_vars((char_u *)s, (char_u *)s, &len, NULL, &errormsg, NULL, false);
    if (p_verbose == 0) {
      emsg_off--;
    } else if (errormsg != NULL) {
      emsg(errormsg);
    }
    if (rettv->v_type == VAR_LIST) {
      tv_list_alloc_ret(rettv, (result != NULL));
      if (result != NULL) {
        tv_list_append_string(rettv->vval.v_list, (const char *)result, -1);
      }
      XFREE_CLEAR(result);
    } else {
      rettv->vval.v_string = (char *)result;
    }
  } else {
    // When the optional second argument is non-zero, don't remove matches
    // for 'wildignore' and don't put matches for 'suffixes' at the end.
    if (argvars[1].v_type != VAR_UNKNOWN
        && tv_get_number_chk(&argvars[1], &error)) {
      options |= WILD_KEEP_ALL;
    }
    if (!error) {
      expand_T xpc;
      ExpandInit(&xpc);
      xpc.xp_context = EXPAND_FILES;
      if (p_wic) {
        options += WILD_ICASE;
      }
      if (rettv->v_type == VAR_STRING) {
        rettv->vval.v_string = ExpandOne(&xpc, (char *)s, NULL, options, WILD_ALL);
      } else {
        ExpandOne(&xpc, (char *)s, NULL, options, WILD_ALL_KEEP);
        tv_list_alloc_ret(rettv, xpc.xp_numfiles);
        for (int i = 0; i < xpc.xp_numfiles; i++) {
          tv_list_append_string(rettv->vval.v_list,
                                (const char *)xpc.xp_files[i], -1);
        }
        ExpandCleanup(&xpc);
      }
    } else {
      rettv->vval.v_string = NULL;
    }
  }
#ifdef BACKSLASH_IN_FILENAME
  p_csl = p_csl_save;
#endif
}

/// "menu_get(path [, modes])" function
static void f_menu_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenMayKnow);
  int modes = MENU_ALL_MODES;
  if (argvars[1].v_type == VAR_STRING) {
    const char *const strmodes = tv_get_string(&argvars[1]);
    modes = get_menu_cmd_modes(strmodes, false, NULL, NULL);
  }
  menu_get((char *)tv_get_string(&argvars[0]), modes, rettv->vval.v_list);
}

/// "expandcmd()" function
/// Expand all the special characters in a command string.
static void f_expandcmd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char *errormsg = NULL;
  bool emsgoff = true;

  if (argvars[1].v_type == VAR_DICT
      && tv_dict_get_bool(argvars[1].vval.v_dict, "errmsg", kBoolVarFalse)) {
    emsgoff = false;
  }

  rettv->v_type = VAR_STRING;
  char *cmdstr = xstrdup(tv_get_string(&argvars[0]));

  exarg_T eap = {
    .cmd = cmdstr,
    .arg = cmdstr,
    .usefilter = false,
    .nextcmd = NULL,
    .cmdidx = CMD_USER,
  };
  eap.argt |= EX_NOSPC;

  if (emsgoff) {
    emsg_off++;
  }
  if (expand_filename(&eap, &cmdstr, &errormsg) == FAIL) {
    if (!emsgoff && errormsg != NULL && *errormsg != NUL) {
      emsg(errormsg);
    }
  }
  if (emsgoff) {
    emsg_off--;
  }

  rettv->vval.v_string = cmdstr;
}

/// "flatten(list[, {maxdepth}])" function
static void f_flatten(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  bool error = false;

  if (argvars[0].v_type != VAR_LIST) {
    semsg(_(e_listarg), "flatten()");
    return;
  }

  long maxdepth;
  if (argvars[1].v_type == VAR_UNKNOWN) {
    maxdepth = 999999;
  } else {
    maxdepth = (long)tv_get_number_chk(&argvars[1], &error);
    if (error) {
      return;
    }
    if (maxdepth < 0) {
      emsg(_("E900: maxdepth must be non-negative number"));
      return;
    }
  }

  list_T *list = argvars[0].vval.v_list;
  if (list != NULL
      && !var_check_lock(tv_list_locked(list),
                         N_("flatten() argument"),
                         TV_TRANSLATE)
      && tv_list_flatten(list, maxdepth) == OK) {
    tv_copy(&argvars[0], rettv);
  }
}

/// "extend(list, list [, idx])" function
/// "extend(dict, dict [, action])" function
static void f_extend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const arg_errmsg = N_("extend() argument");

  if (argvars[0].v_type == VAR_LIST && argvars[1].v_type == VAR_LIST) {
    bool error = false;

    list_T *const l1 = argvars[0].vval.v_list;
    list_T *const l2 = argvars[1].vval.v_list;
    if (!var_check_lock(tv_list_locked(l1), arg_errmsg, TV_TRANSLATE)) {
      listitem_T *item;
      if (argvars[2].v_type != VAR_UNKNOWN) {
        long before = (long)tv_get_number_chk(&argvars[2], &error);
        if (error) {
          return;  // Type error; errmsg already given.
        }

        if (before == tv_list_len(l1)) {
          item = NULL;
        } else {
          item = tv_list_find(l1, (int)before);
          if (item == NULL) {
            semsg(_(e_listidx), (int64_t)before);
            return;
          }
        }
      } else {
        item = NULL;
      }
      tv_list_extend(l1, l2, item);

      tv_copy(&argvars[0], rettv);
    }
  } else if (argvars[0].v_type == VAR_DICT && argvars[1].v_type ==
             VAR_DICT) {
    dict_T *const d1 = argvars[0].vval.v_dict;
    dict_T *const d2 = argvars[1].vval.v_dict;
    if (d1 == NULL) {
      const bool locked = var_check_lock(VAR_FIXED, arg_errmsg, TV_TRANSLATE);
      (void)locked;
      assert(locked == true);
    } else if (d2 == NULL) {
      // Do nothing
      tv_copy(&argvars[0], rettv);
    } else if (!var_check_lock(d1->dv_lock, arg_errmsg, TV_TRANSLATE)) {
      const char *action = "force";
      // Check the third argument.
      if (argvars[2].v_type != VAR_UNKNOWN) {
        const char *const av[] = { "keep", "force", "error" };

        action = tv_get_string_chk(&argvars[2]);
        if (action == NULL) {
          return;  // Type error; error message already given.
        }
        size_t i;
        for (i = 0; i < ARRAY_SIZE(av); i++) {
          if (strcmp(action, av[i]) == 0) {
            break;
          }
        }
        if (i == 3) {
          semsg(_(e_invarg2), action);
          return;
        }
      }

      tv_dict_extend(d1, d2, action);

      tv_copy(&argvars[0], rettv);
    }
  } else {
    semsg(_(e_listdictarg), "extend()");
  }
}

/// "feedkeys()" function
static void f_feedkeys(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // This is not allowed in the sandbox.  If the commands would still be
  // executed in the sandbox it would be OK, but it probably happens later,
  // when "sandbox" is no longer set.
  if (check_secure()) {
    return;
  }

  const char *const keys = tv_get_string(&argvars[0]);
  char nbuf[NUMBUFLEN];
  const char *flags = NULL;
  if (argvars[1].v_type != VAR_UNKNOWN) {
    flags = tv_get_string_buf(&argvars[1], nbuf);
  }

  nvim_feedkeys(cstr_as_string((char *)keys),
                cstr_as_string((char *)flags), true);
}

/// "filereadable()" function
static void f_filereadable(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const p = tv_get_string(&argvars[0]);
  rettv->vval.v_number =
    (*p && !os_isdir(p) && os_file_is_readable(p));
}

/// @return  0 for not writable
///          1 for writable file
///          2 for a dir which we have rights to write into.
static void f_filewritable(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *filename = tv_get_string(&argvars[0]);
  rettv->vval.v_number = os_file_is_writable(filename);
}

static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
{
  char_u *fresult = NULL;
  char_u *path = *curbuf->b_p_path == NUL ? p_path : (char_u *)curbuf->b_p_path;
  int count = 1;
  bool first = true;
  bool error = false;

  rettv->vval.v_string = NULL;
  rettv->v_type = VAR_STRING;

  const char *fname = tv_get_string(&argvars[0]);

  char pathbuf[NUMBUFLEN];
  if (argvars[1].v_type != VAR_UNKNOWN) {
    const char *p = tv_get_string_buf_chk(&argvars[1], pathbuf);
    if (p == NULL) {
      error = true;
    } else {
      if (*p != NUL) {
        path = (char_u *)p;
      }

      if (argvars[2].v_type != VAR_UNKNOWN) {
        count = (int)tv_get_number_chk(&argvars[2], &error);
      }
    }
  }

  if (count < 0) {
    tv_list_alloc_ret(rettv, kListLenUnknown);
  }

  if (*fname != NUL && !error) {
    do {
      if (rettv->v_type == VAR_STRING || rettv->v_type == VAR_LIST) {
        xfree(fresult);
      }
      fresult = (char_u *)find_file_in_path_option(first ? (char *)fname : NULL,
                                                   first ? strlen(fname) : 0,
                                                   0, first, (char *)path,
                                                   find_what, curbuf->b_ffname,
                                                   (find_what == FINDFILE_DIR
                                                    ? ""
                                                    : curbuf->b_p_sua));
      first = false;

      if (fresult != NULL && rettv->v_type == VAR_LIST) {
        tv_list_append_string(rettv->vval.v_list, (const char *)fresult, -1);
      }
    } while ((rettv->v_type == VAR_LIST || --count > 0) && fresult != NULL);
  }

  if (rettv->v_type == VAR_STRING) {
    rettv->vval.v_string = (char *)fresult;
  }
}

/// "filter()" function
static void f_filter(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  filter_map(argvars, rettv, false);
}

/// "finddir({fname}[, {path}[, {count}]])" function
static void f_finddir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  findfilendir(argvars, rettv, FINDFILE_DIR);
}

/// "findfile({fname}[, {path}[, {count}]])" function
static void f_findfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  findfilendir(argvars, rettv, FINDFILE_FILE);
}

/// "float2nr({float})" function
static void f_float2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  float_T f;

  if (!tv_get_float_chk(argvars, &f)) {
    return;
  }

  if (f <= (float_T) - VARNUMBER_MAX + DBL_EPSILON) {
    rettv->vval.v_number = -VARNUMBER_MAX;
  } else if (f >= (float_T)VARNUMBER_MAX - DBL_EPSILON) {
    rettv->vval.v_number = VARNUMBER_MAX;
  } else {
    rettv->vval.v_number = (varnumber_T)f;
  }
}

/// "fmod()" function
static void f_fmod(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  float_T fx;
  float_T fy;

  rettv->v_type = VAR_FLOAT;
  if (tv_get_float_chk(argvars, &fx) && tv_get_float_chk(&argvars[1], &fy)) {
    rettv->vval.v_float = fmod(fx, fy);
  } else {
    rettv->vval.v_float = 0.0;
  }
}

/// "fnameescape({string})" function
static void f_fnameescape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_string = vim_strsave_fnameescape(tv_get_string(&argvars[0]), VSE_NONE);
  rettv->v_type = VAR_STRING;
}

/// "fnamemodify({fname}, {mods})" function
static void f_fnamemodify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char_u *fbuf = NULL;
  size_t len = 0;
  char buf[NUMBUFLEN];
  const char *fname = tv_get_string_chk(&argvars[0]);
  const char *const mods = tv_get_string_buf_chk(&argvars[1], buf);
  if (mods == NULL || fname == NULL) {
    fname = NULL;
  } else {
    len = strlen(fname);
    if (*mods != NUL) {
      size_t usedlen = 0;
      (void)modify_fname((char *)mods, false, &usedlen,
                         (char **)&fname, (char **)&fbuf, &len);
    }
  }

  rettv->v_type = VAR_STRING;
  if (fname == NULL) {
    rettv->vval.v_string = NULL;
  } else {
    rettv->vval.v_string = xmemdupz(fname, len);
  }
  xfree(fbuf);
}

/// "foreground()" function
static void f_foreground(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{}

static void f_funcref(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  common_function(argvars, rettv, true);
}

static void f_function(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  common_function(argvars, rettv, false);
}

/// "garbagecollect()" function
static void f_garbagecollect(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // This is postponed until we are back at the toplevel, because we may be
  // using Lists and Dicts internally.  E.g.: ":echo [garbagecollect()]".
  want_garbage_collect = true;

  if (argvars[0].v_type != VAR_UNKNOWN && tv_get_number(&argvars[0]) == 1) {
    garbage_collect_at_exit = true;
  }
}

/// "get()" function
static void f_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  typval_T *tv = NULL;
  bool what_is_dict = false;

  if (argvars[0].v_type == VAR_BLOB) {
    bool error = false;
    int idx = (int)tv_get_number_chk(&argvars[1], &error);

    if (!error) {
      rettv->v_type = VAR_NUMBER;
      if (idx < 0) {
        idx = tv_blob_len(argvars[0].vval.v_blob) + idx;
      }
      if (idx < 0 || idx >= tv_blob_len(argvars[0].vval.v_blob)) {
        rettv->vval.v_number = -1;
      } else {
        rettv->vval.v_number = tv_blob_get(argvars[0].vval.v_blob, idx);
        tv = rettv;
      }
    }
  } else if (argvars[0].v_type == VAR_LIST) {
    list_T *l = argvars[0].vval.v_list;
    if (l != NULL) {
      bool error = false;

      listitem_T *li = tv_list_find(l, (int)tv_get_number_chk(&argvars[1], &error));
      if (!error && li != NULL) {
        tv = TV_LIST_ITEM_TV(li);
      }
    }
  } else if (argvars[0].v_type == VAR_DICT) {
    dict_T *d = argvars[0].vval.v_dict;
    if (d != NULL) {
      dictitem_T *di = tv_dict_find(d, tv_get_string(&argvars[1]), -1);
      if (di != NULL) {
        tv = &di->di_tv;
      }
    }
  } else if (tv_is_func(argvars[0])) {
    partial_T *pt;
    partial_T fref_pt;

    if (argvars[0].v_type == VAR_PARTIAL) {
      pt = argvars[0].vval.v_partial;
    } else {
      CLEAR_FIELD(fref_pt);
      fref_pt.pt_name = argvars[0].vval.v_string;
      pt = &fref_pt;
    }

    if (pt != NULL) {
      const char *const what = tv_get_string(&argvars[1]);

      if (strcmp(what, "func") == 0 || strcmp(what, "name") == 0) {
        const char *name = (const char *)partial_name(pt);
        rettv->v_type = (*what == 'f' ? VAR_FUNC : VAR_STRING);
        assert(name != NULL);
        if (rettv->v_type == VAR_FUNC) {
          func_ref((char_u *)name);
        }
        if (*what == 'n' && pt->pt_name == NULL && pt->pt_func != NULL) {
          // use <SNR> instead of the byte code
          name = (const char *)printable_func_name(pt->pt_func);
        }
        rettv->vval.v_string = xstrdup(name);
      } else if (strcmp(what, "dict") == 0) {
        what_is_dict = true;
        if (pt->pt_dict != NULL) {
          tv_dict_set_ret(rettv, pt->pt_dict);
        }
      } else if (strcmp(what, "args") == 0) {
        rettv->v_type = VAR_LIST;
        tv_list_alloc_ret(rettv, pt->pt_argc);
        for (int i = 0; i < pt->pt_argc; i++) {
          tv_list_append_tv(rettv->vval.v_list, &pt->pt_argv[i]);
        }
      } else {
        semsg(_(e_invarg2), what);
      }

      // When {what} == "dict" and pt->pt_dict == NULL, evaluate the
      // third argument
      if (!what_is_dict) {
        return;
      }
    }
  } else {
    semsg(_(e_listdictblobarg), "get()");
  }

  if (tv == NULL) {
    if (argvars[2].v_type != VAR_UNKNOWN) {
      tv_copy(&argvars[2], rettv);
    }
  } else {
    tv_copy(tv, rettv);
  }
}

/// "getchangelist()" function
static void f_getchangelist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, 2);

  const buf_T *buf;
  if (argvars[0].v_type == VAR_UNKNOWN) {
    buf = curbuf;
  } else {
    vim_ignored = (int)tv_get_number(&argvars[0]);  // issue errmsg if type error
    emsg_off++;
    buf = tv_get_buf(&argvars[0], false);
    emsg_off--;
  }
  if (buf == NULL) {
    return;
  }

  list_T *const l = tv_list_alloc(buf->b_changelistlen);
  tv_list_append_list(rettv->vval.v_list, l);
  // The current window change list index tracks only the position for the
  // current buffer. For other buffers use the stored index for the current
  // window, or, if that's not available, the change list length.
  int changelistindex;
  if (buf == curwin->w_buffer) {
    changelistindex = curwin->w_changelistidx;
  } else {
    wininfo_T *wip;

    FOR_ALL_BUF_WININFO(buf, wip) {
      if (wip->wi_win == curwin) {
        break;
      }
    }
    changelistindex = wip != NULL ? wip->wi_changelistidx : buf->b_changelistlen;
  }
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)changelistindex);

  for (int i = 0; i < buf->b_changelistlen; i++) {
    if (buf->b_changelist[i].mark.lnum == 0) {
      continue;
    }
    dict_T *const d = tv_dict_alloc();
    tv_list_append_dict(l, d);
    tv_dict_add_nr(d, S_LEN("lnum"), buf->b_changelist[i].mark.lnum);
    tv_dict_add_nr(d, S_LEN("col"), buf->b_changelist[i].mark.col);
    tv_dict_add_nr(d, S_LEN("coladd"), buf->b_changelist[i].mark.coladd);
  }
}

static void getpos_both(typval_T *argvars, typval_T *rettv, bool getcurpos, bool charcol)
{
  pos_T *fp = NULL;
  pos_T pos;
  win_T *wp = curwin;
  int fnum = -1;

  if (getcurpos) {
    if (argvars[0].v_type != VAR_UNKNOWN) {
      wp = find_win_by_nr_or_id(&argvars[0]);
      if (wp != NULL) {
        fp = &wp->w_cursor;
      }
    } else {
      fp = &curwin->w_cursor;
    }
    if (fp != NULL && charcol) {
      pos = *fp;
      pos.col = buf_byteidx_to_charidx(wp->w_buffer, pos.lnum, pos.col);
      fp = &pos;
    }
  } else {
    fp = var2fpos(&argvars[0], true, &fnum, charcol);
  }

  list_T *const l = tv_list_alloc_ret(rettv, 4 + getcurpos);
  tv_list_append_number(l, (fnum != -1) ? (varnumber_T)fnum : (varnumber_T)0);
  tv_list_append_number(l, ((fp != NULL) ? (varnumber_T)fp->lnum : (varnumber_T)0));
  tv_list_append_number(l, ((fp != NULL)
                            ? (varnumber_T)(fp->col == MAXCOL ? MAXCOL : fp->col + 1)
                            : (varnumber_T)0));
  tv_list_append_number(l, (fp != NULL) ? (varnumber_T)fp->coladd : (varnumber_T)0);
  if (getcurpos) {
    const int save_set_curswant = curwin->w_set_curswant;
    const colnr_T save_curswant = curwin->w_curswant;
    const colnr_T save_virtcol = curwin->w_virtcol;

    if (wp == curwin) {
      update_curswant();
    }
    tv_list_append_number(l, (wp == NULL) ? 0 : ((wp->w_curswant == MAXCOL)
                                                 ? (varnumber_T)MAXCOL
                                                 : (varnumber_T)wp->w_curswant + 1));

    // Do not change "curswant", as it is unexpected that a get
    // function has a side effect.
    if (wp == curwin && save_set_curswant) {
      curwin->w_set_curswant = save_set_curswant;
      curwin->w_curswant = save_curswant;
      curwin->w_virtcol = save_virtcol;
      curwin->w_valid &= ~VALID_VIRTCOL;
    }
  }
}

/// "getcharpos()" function
static void f_getcharpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  getpos_both(argvars, rettv, false, true);
}

/// "getcharsearch()" function
static void f_getcharsearch(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);

  dict_T *dict = rettv->vval.v_dict;

  tv_dict_add_str(dict, S_LEN("char"), last_csearch());
  tv_dict_add_nr(dict, S_LEN("forward"), last_csearch_forward());
  tv_dict_add_nr(dict, S_LEN("until"), last_csearch_until());
}

/// `getcwd([{win}[, {tab}]])` function
///
/// Every scope not specified implies the currently selected scope object.
///
/// @pre  The arguments must be of type number.
/// @pre  There may not be more than two arguments.
/// @pre  An argument may not be -1 if preceding arguments are not all -1.
///
/// @post  The return value will be a string.
static void f_getcwd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // Possible scope of working directory to return.
  CdScope scope = kCdScopeInvalid;

  // Numbers of the scope objects (window, tab) we want the working directory
  // of. A `-1` means to skip this scope, a `0` means the current object.
  int scope_number[] = {
    [kCdScopeWindow] = 0,   // Number of window to look at.
    [kCdScopeTabpage] = 0,  // Number of tab to look at.
  };

  char *cwd  = NULL;    // Current working directory to print
  char *from = NULL;    // The original string to copy

  tabpage_T *tp = curtab;  // The tabpage to look at.
  win_T *win = curwin;     // The window to look at.

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  // Pre-conditions and scope extraction together
  for (int i = MIN_CD_SCOPE; i < MAX_CD_SCOPE; i++) {
    // If there is no argument there are no more scopes after it, break out.
    if (argvars[i].v_type == VAR_UNKNOWN) {
      break;
    }
    if (argvars[i].v_type != VAR_NUMBER) {
      emsg(_(e_invarg));
      return;
    }
    scope_number[i] = (int)argvars[i].vval.v_number;
    // It is an error for the scope number to be less than `-1`.
    if (scope_number[i] < -1) {
      emsg(_(e_invarg));
      return;
    }
    // Use the narrowest scope the user requested
    if (scope_number[i] >= 0 && scope == kCdScopeInvalid) {
      // The scope is the current iteration step.
      scope = i;
    } else if (scope_number[i] < 0) {
      scope = i + 1;
    }
  }

  // Find the tabpage by number
  if (scope_number[kCdScopeTabpage] > 0) {
    tp = find_tabpage(scope_number[kCdScopeTabpage]);
    if (!tp) {
      emsg(_("E5000: Cannot find tab number."));
      return;
    }
  }

  // Find the window in `tp` by number, `NULL` if none.
  if (scope_number[kCdScopeWindow] >= 0) {
    if (scope_number[kCdScopeTabpage] < 0) {
      emsg(_("E5001: Higher scope cannot be -1 if lower scope is >= 0."));
      return;
    }

    if (scope_number[kCdScopeWindow] > 0) {
      win = find_win_by_nr(&argvars[0], tp);
      if (!win) {
        emsg(_("E5002: Cannot find window number."));
        return;
      }
    }
  }

  cwd = xmalloc(MAXPATHL);

  switch (scope) {
  case kCdScopeWindow:
    assert(win);
    from = win->w_localdir;
    if (from) {
      break;
    }
    FALLTHROUGH;
  case kCdScopeTabpage:
    assert(tp);
    from = tp->tp_localdir;
    if (from) {
      break;
    }
    FALLTHROUGH;
  case kCdScopeGlobal:
    if (globaldir) {        // `globaldir` is not always set.
      from = globaldir;
      break;
    }
    FALLTHROUGH;            // In global directory, just need to get OS CWD.
  case kCdScopeInvalid:     // If called without any arguments, get OS CWD.
    if (os_dirname((char_u *)cwd, MAXPATHL) == FAIL) {
      from = "";  // Return empty string on failure.
    }
  }

  if (from) {
    STRLCPY(cwd, from, MAXPATHL);
  }

  rettv->vval.v_string = xstrdup(cwd);
#ifdef BACKSLASH_IN_FILENAME
  slash_adjust(rettv->vval.v_string);
#endif

  xfree(cwd);
}

/// "getfontname()" function
static void f_getfontname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
}

/// "getfperm({fname})" function
static void f_getfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char *perm = NULL;
  char_u flags[] = "rwx";

  const char *filename = tv_get_string(&argvars[0]);
  int32_t file_perm = os_getperm(filename);
  if (file_perm >= 0) {
    perm = xstrdup("---------");
    for (int i = 0; i < 9; i++) {
      if (file_perm & (1 << (8 - i))) {
        perm[i] = (char)flags[i % 3];
      }
    }
  }
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = perm;
}

/// "getfsize({fname})" function
static void f_getfsize(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *fname = tv_get_string(&argvars[0]);

  rettv->v_type = VAR_NUMBER;

  FileInfo file_info;
  if (os_fileinfo(fname, &file_info)) {
    uint64_t filesize = os_fileinfo_size(&file_info);
    if (os_isdir(fname)) {
      rettv->vval.v_number = 0;
    } else {
      rettv->vval.v_number = (varnumber_T)filesize;

      // non-perfect check for overflow
      if ((uint64_t)rettv->vval.v_number != filesize) {
        rettv->vval.v_number = -2;
      }
    }
  } else {
    rettv->vval.v_number = -1;
  }
}

/// "getftime({fname})" function
static void f_getftime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *fname = tv_get_string(&argvars[0]);

  FileInfo file_info;
  if (os_fileinfo(fname, &file_info)) {
    rettv->vval.v_number = (varnumber_T)file_info.stat.st_mtim.tv_sec;
  } else {
    rettv->vval.v_number = -1;
  }
}

/// "getftype({fname})" function
static void f_getftype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char *type = NULL;
  char *t;

  const char *fname = tv_get_string(&argvars[0]);

  rettv->v_type = VAR_STRING;
  FileInfo file_info;
  if (os_fileinfo_link(fname, &file_info)) {
    uint64_t mode = file_info.stat.st_mode;
    if (S_ISREG(mode)) {
      t = "file";
    } else if (S_ISDIR(mode)) {
      t = "dir";
    } else if (S_ISLNK(mode)) {
      t = "link";
    } else if (S_ISBLK(mode)) {
      t = "bdev";
    } else if (S_ISCHR(mode)) {
      t = "cdev";
    } else if (S_ISFIFO(mode)) {
      t = "fifo";
    } else if (S_ISSOCK(mode)) {
      t = "socket";
    } else {
      t = "other";
    }
    type = xstrdup(t);
  }
  rettv->vval.v_string = type;
}

/// "getjumplist()" function
static void f_getjumplist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenMayKnow);
  win_T *const wp = find_tabwin(&argvars[0], &argvars[1]);
  if (wp == NULL) {
    return;
  }

  cleanup_jumplist(wp, true);

  list_T *const l = tv_list_alloc(wp->w_jumplistlen);
  tv_list_append_list(rettv->vval.v_list, l);
  tv_list_append_number(rettv->vval.v_list, wp->w_jumplistidx);

  for (int i = 0; i < wp->w_jumplistlen; i++) {
    if (wp->w_jumplist[i].fmark.mark.lnum == 0) {
      continue;
    }
    dict_T *const d = tv_dict_alloc();
    tv_list_append_dict(l, d);
    tv_dict_add_nr(d, S_LEN("lnum"), wp->w_jumplist[i].fmark.mark.lnum);
    tv_dict_add_nr(d, S_LEN("col"), wp->w_jumplist[i].fmark.mark.col);
    tv_dict_add_nr(d, S_LEN("coladd"), wp->w_jumplist[i].fmark.mark.coladd);
    tv_dict_add_nr(d, S_LEN("bufnr"), wp->w_jumplist[i].fmark.fnum);
    if (wp->w_jumplist[i].fname != NULL) {
      tv_dict_add_str(d, S_LEN("filename"), wp->w_jumplist[i].fname);
    }
  }
}

/// "getmarklist()" function
static void f_getmarklist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenMayKnow);

  if (argvars[0].v_type == VAR_UNKNOWN) {
    get_global_marks(rettv->vval.v_list);
    return;
  }

  buf_T *buf = tv_get_buf(&argvars[0], false);
  if (buf == NULL) {
    return;
  }

  get_buf_local_marks(buf, rettv->vval.v_list);
}

/// "getmousepos()" function
static void f_getmousepos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int row = mouse_row;
  int col = mouse_col;
  int grid = mouse_grid;
  varnumber_T winid = 0;
  varnumber_T winrow = 0;
  varnumber_T wincol = 0;
  linenr_T lnum = 0;
  varnumber_T column = 0;

  tv_dict_alloc_ret(rettv);
  dict_T *d = rettv->vval.v_dict;

  tv_dict_add_nr(d, S_LEN("screenrow"), (varnumber_T)mouse_row + 1);
  tv_dict_add_nr(d, S_LEN("screencol"), (varnumber_T)mouse_col + 1);

  win_T *wp = mouse_find_win(&grid, &row, &col);
  if (wp != NULL) {
    int height = wp->w_height + wp->w_hsep_height + wp->w_status_height;
    // The height is adjusted by 1 when there is a bottom border. This is not
    // necessary for a top border since `row` starts at -1 in that case.
    if (row < height + wp->w_border_adj[2]) {
      winid = wp->handle;
      winrow = row + 1 + wp->w_winrow_off;  // Adjust by 1 for top border
      wincol = col + 1 + wp->w_wincol_off;  // Adjust by 1 for left border
      if (row >= 0 && row < wp->w_height && col >= 0 && col < wp->w_width) {
        (void)mouse_comp_pos(wp, &row, &col, &lnum);
        col = vcol2col(wp, lnum, col);
        column = col + 1;
      }
    }
  }
  tv_dict_add_nr(d, S_LEN("winid"), winid);
  tv_dict_add_nr(d, S_LEN("winrow"), winrow);
  tv_dict_add_nr(d, S_LEN("wincol"), wincol);
  tv_dict_add_nr(d, S_LEN("line"), (varnumber_T)lnum);
  tv_dict_add_nr(d, S_LEN("column"), column);
}

/// "getpid()" function
static void f_getpid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = os_get_pid();
}

/// "getcurpos(string)" function
static void f_getcurpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  getpos_both(argvars, rettv, true, false);
}

static void f_getcursorcharpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  getpos_both(argvars, rettv, true, true);
}

/// "getpos(string)" function
static void f_getpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  getpos_both(argvars, rettv, false, false);
}

/// Common between getreg(), getreginfo() and getregtype(): get the register
/// name from the first argument.
/// Returns zero on error.
static int getreg_get_regname(typval_T *argvars)
{
  const char_u *strregname;

  if (argvars[0].v_type != VAR_UNKNOWN) {
    strregname = (const char_u *)tv_get_string_chk(&argvars[0]);
    if (strregname == NULL) {  // type error; errmsg already given
      return 0;
    }
  } else {
    // Default to v:register
    strregname = (char_u *)get_vim_var_str(VV_REG);
  }

  return *strregname == 0 ? '"' : *strregname;
}

/// "getreg()" function
static void f_getreg(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int arg2 = false;
  bool return_list = false;

  int regname = getreg_get_regname(argvars);
  if (regname == 0) {
    return;
  }

  if (argvars[0].v_type != VAR_UNKNOWN && argvars[1].v_type != VAR_UNKNOWN) {
    bool error = false;
    arg2 = (int)tv_get_number_chk(&argvars[1], &error);
    if (!error && argvars[2].v_type != VAR_UNKNOWN) {
      return_list = (bool)tv_get_number_chk(&argvars[2], &error);
    }
    if (error) {
      return;
    }
  }

  if (return_list) {
    rettv->v_type = VAR_LIST;
    rettv->vval.v_list =
      get_reg_contents(regname, (arg2 ? kGRegExprSrc : 0) | kGRegList);
    if (rettv->vval.v_list == NULL) {
      rettv->vval.v_list = tv_list_alloc(0);
    }
    tv_list_ref(rettv->vval.v_list);
  } else {
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = get_reg_contents(regname, arg2 ? kGRegExprSrc : 0);
  }
}

/// "getregtype()" function
static void f_getregtype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // on error return an empty string
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  int regname = getreg_get_regname(argvars);
  if (regname == 0) {
    return;
  }

  colnr_T reglen = 0;
  char buf[NUMBUFLEN + 2];
  MotionType reg_type = get_reg_type(regname, &reglen);
  format_reg_type(reg_type, reglen, buf, ARRAY_SIZE(buf));

  rettv->vval.v_string = xstrdup(buf);
}

/// "gettagstack()" function
static void f_gettagstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  win_T *wp = curwin;                  // default is current window

  tv_dict_alloc_ret(rettv);

  if (argvars[0].v_type != VAR_UNKNOWN) {
    wp = find_win_by_nr_or_id(&argvars[0]);
    if (wp == NULL) {
      return;
    }
  }

  get_tagstack(wp, rettv->vval.v_dict);
}

/// Dummy timer callback. Used by f_wait().
static void dummy_timer_due_cb(TimeWatcher *tw, void *data)
{}

/// Dummy timer close callback. Used by f_wait().
static void dummy_timer_close_cb(TimeWatcher *tw, void *data)
{
  xfree(tw);
}

/// "wait(timeout, condition[, interval])" function
static void f_wait(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = -1;

  if (argvars[0].v_type != VAR_NUMBER) {
    semsg(_(e_invargval), "1");
    return;
  }
  if ((argvars[2].v_type != VAR_NUMBER && argvars[2].v_type != VAR_UNKNOWN)
      || (argvars[2].v_type == VAR_NUMBER && argvars[2].vval.v_number <= 0)) {
    semsg(_(e_invargval), "3");
    return;
  }

  int timeout = (int)argvars[0].vval.v_number;
  typval_T expr = argvars[1];
  int interval = argvars[2].v_type == VAR_NUMBER
    ? (int)argvars[2].vval.v_number
    : 200;  // Default.
  TimeWatcher *tw = xmalloc(sizeof(TimeWatcher));

  // Start dummy timer.
  time_watcher_init(&main_loop, tw, NULL);
  tw->events = main_loop.events;
  tw->blockable = true;
  time_watcher_start(tw, dummy_timer_due_cb, (uint64_t)interval, (uint64_t)interval);

  typval_T argv = TV_INITIAL_VALUE;
  typval_T exprval = TV_INITIAL_VALUE;
  bool error = false;
  const int called_emsg_before = called_emsg;

  LOOP_PROCESS_EVENTS_UNTIL(&main_loop, main_loop.events, timeout,
                            eval_expr_typval(&expr, &argv, 0, &exprval) != OK
                            || tv_get_number_chk(&exprval, &error)
                            || called_emsg > called_emsg_before || error || got_int);

  if (called_emsg > called_emsg_before || error) {
    rettv->vval.v_number = -3;
  } else if (got_int) {
    got_int = false;
    vgetc();
    rettv->vval.v_number = -2;
  } else if (tv_get_number_chk(&exprval, &error)) {
    rettv->vval.v_number = 0;
  }

  // Stop dummy timer
  time_watcher_stop(tw);
  time_watcher_close(tw, dummy_timer_close_cb);
}

/// "glob()" function
static void f_glob(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int options = WILD_SILENT|WILD_USE_NL;
  expand_T xpc;
  bool error = false;

  // When the optional second argument is non-zero, don't remove matches
  // for 'wildignore' and don't put matches for 'suffixes' at the end.
  rettv->v_type = VAR_STRING;
  if (argvars[1].v_type != VAR_UNKNOWN) {
    if (tv_get_number_chk(&argvars[1], &error)) {
      options |= WILD_KEEP_ALL;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      if (tv_get_number_chk(&argvars[2], &error)) {
        tv_list_set_ret(rettv, NULL);
      }
      if (argvars[3].v_type != VAR_UNKNOWN
          && tv_get_number_chk(&argvars[3], &error)) {
        options |= WILD_ALLLINKS;
      }
    }
  }
  if (!error) {
    ExpandInit(&xpc);
    xpc.xp_context = EXPAND_FILES;
    if (p_wic) {
      options += WILD_ICASE;
    }
    if (rettv->v_type == VAR_STRING) {
      rettv->vval.v_string = ExpandOne(&xpc, (char *)
                                       tv_get_string(&argvars[0]), NULL, options,
                                       WILD_ALL);
    } else {
      ExpandOne(&xpc, (char *)tv_get_string(&argvars[0]), NULL, options,
                WILD_ALL_KEEP);
      tv_list_alloc_ret(rettv, xpc.xp_numfiles);
      for (int i = 0; i < xpc.xp_numfiles; i++) {
        tv_list_append_string(rettv->vval.v_list, (const char *)xpc.xp_files[i],
                              -1);
      }
      ExpandCleanup(&xpc);
    }
  } else {
    rettv->vval.v_string = NULL;
  }
}

/// "globpath()" function
static void f_globpath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int flags = WILD_IGNORE_COMPLETESLASH;  // Flags for globpath.
  bool error = false;

  // Return a string, or a list if the optional third argument is non-zero.
  rettv->v_type = VAR_STRING;

  if (argvars[2].v_type != VAR_UNKNOWN) {
    // When the optional second argument is non-zero, don't remove matches
    // for 'wildignore' and don't put matches for 'suffixes' at the end.
    if (tv_get_number_chk(&argvars[2], &error)) {
      flags |= WILD_KEEP_ALL;
    }

    if (argvars[3].v_type != VAR_UNKNOWN) {
      if (tv_get_number_chk(&argvars[3], &error)) {
        tv_list_set_ret(rettv, NULL);
      }
      if (argvars[4].v_type != VAR_UNKNOWN
          && tv_get_number_chk(&argvars[4], &error)) {
        flags |= WILD_ALLLINKS;
      }
    }
  }

  char buf1[NUMBUFLEN];
  const char *const file = tv_get_string_buf_chk(&argvars[1], buf1);
  if (file != NULL && !error) {
    garray_T ga;
    ga_init(&ga, (int)sizeof(char_u *), 10);
    globpath((char *)tv_get_string(&argvars[0]), (char *)file, &ga, flags);

    if (rettv->v_type == VAR_STRING) {
      rettv->vval.v_string = ga_concat_strings_sep(&ga, "\n");
    } else {
      tv_list_alloc_ret(rettv, ga.ga_len);
      for (int i = 0; i < ga.ga_len; i++) {
        tv_list_append_string(rettv->vval.v_list,
                              ((const char **)(ga.ga_data))[i], -1);
      }
    }

    ga_clear_strings(&ga);
  } else {
    rettv->vval.v_string = NULL;
  }
}

/// "glob2regpat()" function
static void f_glob2regpat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const pat = tv_get_string_chk(&argvars[0]);  // NULL on type error

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = (pat == NULL) ? NULL : file_pat_to_reg_pat(pat, NULL, NULL, false);
}

/// "gettext()" function
static void f_gettext(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_STRING
      || argvars[0].vval.v_string == NULL
      || *argvars[0].vval.v_string == NUL) {
    semsg(_(e_invarg2), tv_get_string(&argvars[0]));
  } else {
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = xstrdup(_(argvars[0].vval.v_string));
  }
}

/// "has()" function
static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  static const char *const has_list[] = {
#if defined(BSD) && !defined(__APPLE__)
    "bsd",
#endif
#ifdef __linux__
    "linux",
#endif
#ifdef SUN_SYSTEM
    "sun",
#endif
#ifdef UNIX
    "unix",
#endif
#ifdef MSWIN
    "win32",
#endif
#ifdef _WIN64
    "win64",
#endif
#ifndef CASE_INSENSITIVE_FILENAME
    "fname_case",
#endif
#ifdef HAVE_ACL
    "acl",
#endif
    "autochdir",
    "arabic",
    "autocmd",
    "browsefilter",
    "byte_offset",
    "cindent",
    "cmdline_compl",
    "cmdline_hist",
    "cmdwin",
    "comments",
    "conceal",
    "cursorbind",
    "cursorshape",
#ifdef DEBUG
    "debug",
#endif
    "dialog_con",
    "diff",
    "digraphs",
    "eval",         // always present, of course!
    "ex_extra",
    "extra_search",
    "file_in_path",
    "filterpipe",
    "find_in_path",
    "float",
    "folding",
#if defined(UNIX)
    "fork",
#endif
    "gettext",
#if defined(HAVE_ICONV)
    "iconv",
#endif
    "insert_expand",
    "jumplist",
    "keymap",
    "lambda",
    "langmap",
    "libcall",
    "linebreak",
    "lispindent",
    "listcmds",
    "localmap",
#ifdef __APPLE__
    "mac",
    "macunix",
    "osx",
    "osxdarwin",
#endif
    "menu",
    "mksession",
    "modify_fname",
    "mouse",
    "multi_byte",
    "multi_lang",
    "nanotime",
    "num64",
    "packages",
    "path_extra",
    "persistent_undo",
    "profile",
    "pythonx",
    "reltime",
    "quickfix",
    "rightleft",
    "scrollbind",
    "showcmd",
    "cmdline_info",
    "shada",
    "signs",
    "smartindent",
    "startuptime",
    "statusline",
    "spell",
    "syntax",
#if !defined(UNIX)
    "system",
#endif
    "tablineat",
    "tag_binary",
    "termguicolors",
    "termresponse",
    "textobjects",
    "timers",
    "title",
    "user-commands",        // was accidentally included in 5.4
    "user_commands",
    "vartabs",
    "vertsplit",
    "vimscript-1",
    "virtualedit",
    "visual",
    "visualextra",
    "vreplace",
    "wildignore",
    "wildmenu",
    "windows",
    "winaltkeys",
    "writebackup",
    "nvim",
  };

  // XXX: eval_has_provider() may shell out :(
  const int save_shell_error = (int)get_vim_var_nr(VV_SHELL_ERROR);
  bool n = false;
  const char *const name = tv_get_string(&argvars[0]);
  for (size_t i = 0; i < ARRAY_SIZE(has_list); i++) {
    if (STRICMP(name, has_list[i]) == 0) {
      n = true;
      break;
    }
  }

  if (!n) {
    if (STRNICMP(name, "patch", 5) == 0) {
      if (name[5] == '-'
          && strlen(name) >= 11
          && ascii_isdigit(name[6])
          && ascii_isdigit(name[8])
          && ascii_isdigit(name[10])) {
        int major = atoi(name + 6);
        int minor = atoi(name + 8);

        // Expect "patch-9.9.01234".
        n = (major < VIM_VERSION_MAJOR
             || (major == VIM_VERSION_MAJOR
                 && (minor < VIM_VERSION_MINOR
                     || (minor == VIM_VERSION_MINOR
                         && has_vim_patch(atoi(name + 10))))));
      } else {
        n = has_vim_patch(atoi(name + 5));
      }
    } else if (STRNICMP(name, "nvim-", 5) == 0) {
      // Expect "nvim-x.y.z"
      n = has_nvim_version(name + 5);
    } else if (STRICMP(name, "vim_starting") == 0) {
      n = (starting != 0);
    } else if (STRICMP(name, "ttyin") == 0) {
      n = stdin_isatty;
    } else if (STRICMP(name, "ttyout") == 0) {
      n = stdout_isatty;
    } else if (STRICMP(name, "multi_byte_encoding") == 0) {
      n = true;
    } else if (STRICMP(name, "syntax_items") == 0) {
      n = syntax_present(curwin);
    } else if (STRICMP(name, "clipboard_working") == 0) {
      n = eval_has_provider("clipboard");
    } else if (STRICMP(name, "wsl") == 0) {
      n = has_wsl();
#ifdef UNIX
    } else if (STRICMP(name, "unnamedplus") == 0) {
      n = eval_has_provider("clipboard");
#endif
    }
  }

  if (!n && eval_has_provider(name)) {
    n = true;
  }

  set_vim_var_nr(VV_SHELL_ERROR, save_shell_error);
  rettv->vval.v_number = n;
}

static bool has_wsl(void)
{
  static TriState has_wsl = kNone;
  if (has_wsl == kNone) {
    Error err = ERROR_INIT;
    Object o = nlua_exec(STATIC_CSTR_AS_STRING("return vim.loop.os_uname()['release']:lower()"
                                               ":match('microsoft') and true or false"),
                         (Array)ARRAY_DICT_INIT, &err);
    assert(!ERROR_SET(&err));
    assert(o.type == kObjectTypeBoolean);
    has_wsl = o.data.boolean ? kTrue : kFalse;
    api_free_object(o);
  }
  return has_wsl == kTrue;
}

/// `haslocaldir([{win}[, {tab}]])` function
///
/// Returns `1` if the scope object has a local directory, `0` otherwise. If a
/// scope object is not specified the current one is implied. This function
/// share a lot of code with `f_getcwd`.
///
/// @pre  The arguments must be of type number.
/// @pre  There may not be more than two arguments.
/// @pre  An argument may not be -1 if preceding arguments are not all -1.
///
/// @post  The return value will be either the number `1` or `0`.
static void f_haslocaldir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // Possible scope of working directory to return.
  CdScope scope = kCdScopeInvalid;

  // Numbers of the scope objects (window, tab) we want the working directory
  // of. A `-1` means to skip this scope, a `0` means the current object.
  int scope_number[] = {
    [kCdScopeWindow] = 0,  // Number of window to look at.
    [kCdScopeTabpage] = 0,  // Number of tab to look at.
  };

  tabpage_T *tp  = curtab;  // The tabpage to look at.
  win_T *win = curwin;  // The window to look at.

  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  // Pre-conditions and scope extraction together
  for (int i = MIN_CD_SCOPE; i < MAX_CD_SCOPE; i++) {
    if (argvars[i].v_type == VAR_UNKNOWN) {
      break;
    }
    if (argvars[i].v_type != VAR_NUMBER) {
      emsg(_(e_invarg));
      return;
    }
    scope_number[i] = (int)argvars[i].vval.v_number;
    if (scope_number[i] < -1) {
      emsg(_(e_invarg));
      return;
    }
    // Use the narrowest scope the user requested
    if (scope_number[i] >= 0 && scope == kCdScopeInvalid) {
      // The scope is the current iteration step.
      scope = i;
    } else if (scope_number[i] < 0) {
      scope = i + 1;
    }
  }

  // If the user didn't specify anything, default to window scope
  if (scope == kCdScopeInvalid) {
    scope = MIN_CD_SCOPE;
  }

  // Find the tabpage by number
  if (scope_number[kCdScopeTabpage] > 0) {
    tp = find_tabpage(scope_number[kCdScopeTabpage]);
    if (!tp) {
      emsg(_("E5000: Cannot find tab number."));
      return;
    }
  }

  // Find the window in `tp` by number, `NULL` if none.
  if (scope_number[kCdScopeWindow] >= 0) {
    if (scope_number[kCdScopeTabpage] < 0) {
      emsg(_("E5001: Higher scope cannot be -1 if lower scope is >= 0."));
      return;
    }

    if (scope_number[kCdScopeWindow] > 0) {
      win = find_win_by_nr(&argvars[0], tp);
      if (!win) {
        emsg(_("E5002: Cannot find window number."));
        return;
      }
    }
  }

  switch (scope) {
  case kCdScopeWindow:
    assert(win);
    rettv->vval.v_number = win->w_localdir ? 1 : 0;
    break;
  case kCdScopeTabpage:
    assert(tp);
    rettv->vval.v_number = tp->tp_localdir ? 1 : 0;
    break;
  case kCdScopeGlobal:
    // The global scope never has a local directory
    break;
  case kCdScopeInvalid:
    // We should never get here
    abort();
  }
}

/// "highlightID(name)" function
static void f_hlID(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = syn_name2id(tv_get_string(&argvars[0]));
}

/// "highlight_exists()" function
static void f_hlexists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = highlight_exists(tv_get_string(&argvars[0]));
}

/// "hostname()" function
static void f_hostname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char hostname[256];

  os_get_hostname(hostname, 256);
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xstrdup(hostname);
}

/// iconv() function
static void f_iconv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  vimconv_T vimconv;

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  const char *const str = tv_get_string(&argvars[0]);
  char buf1[NUMBUFLEN];
  char_u *const from =
    (char_u *)enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[1], buf1)));
  char buf2[NUMBUFLEN];
  char_u *const to =
    (char_u *)enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[2], buf2)));
  vimconv.vc_type = CONV_NONE;
  convert_setup(&vimconv, (char *)from, (char *)to);

  // If the encodings are equal, no conversion needed.
  if (vimconv.vc_type == CONV_NONE) {
    rettv->vval.v_string = xstrdup(str);
  } else {
    rettv->vval.v_string = string_convert(&vimconv, (char *)str, NULL);
  }

  convert_setup(&vimconv, NULL, NULL);
  xfree(from);
  xfree(to);
}

/// "indent()" function
static void f_indent(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const linenr_T lnum = tv_get_lnum(argvars);
  if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count) {
    rettv->vval.v_number = get_indent_lnum(lnum);
  } else {
    rettv->vval.v_number = -1;
  }
}

/// "index()" function
static void f_index(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  long idx = 0;
  bool ic = false;

  rettv->vval.v_number = -1;
  if (argvars[0].v_type == VAR_BLOB) {
    bool error = false;
    int start = 0;

    if (argvars[2].v_type != VAR_UNKNOWN) {
      start = (int)tv_get_number_chk(&argvars[2], &error);
      if (error) {
        return;
      }
    }
    blob_T *const b = argvars[0].vval.v_blob;
    if (b == NULL) {
      return;
    }
    if (start < 0) {
      start = tv_blob_len(b) + start;
      if (start < 0) {
        start = 0;
      }
    }
    for (idx = start; idx < tv_blob_len(b); idx++) {
      typval_T tv;
      tv.v_type = VAR_NUMBER;
      tv.vval.v_number = tv_blob_get(b, (int)idx);
      if (tv_equal(&tv, &argvars[1], ic, false)) {
        rettv->vval.v_number = idx;
        return;
      }
    }
    return;
  } else if (argvars[0].v_type != VAR_LIST) {
    emsg(_(e_listblobreq));
    return;
  }

  list_T *const l = argvars[0].vval.v_list;
  if (l == NULL) {
    return;
  }

  listitem_T *item = tv_list_first(l);
  if (argvars[2].v_type != VAR_UNKNOWN) {
    bool error = false;

    // Start at specified item.
    idx = tv_list_uidx(l, (int)tv_get_number_chk(&argvars[2], &error));
    if (error || idx == -1) {
      item = NULL;
    } else {
      item = tv_list_find(l, (int)idx);
      assert(item != NULL);
    }
    if (argvars[3].v_type != VAR_UNKNOWN) {
      ic = !!tv_get_number_chk(&argvars[3], &error);
      if (error) {
        item = NULL;
      }
    }
  }

  for (; item != NULL; item = TV_LIST_ITEM_NEXT(l, item), idx++) {
    if (tv_equal(TV_LIST_ITEM_TV(item), &argvars[1], ic, false)) {
      rettv->vval.v_number = idx;
      break;
    }
  }
}

static bool inputsecret_flag = false;

/// "input()" function
///     Also handles inputsecret() when inputsecret is set.
static void f_input(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_user_input(argvars, rettv, false, inputsecret_flag);
}

/// "inputdialog()" function
static void f_inputdialog(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_user_input(argvars, rettv, true, inputsecret_flag);
}

/// "inputlist()" function
static void f_inputlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_LIST) {
    semsg(_(e_listarg), "inputlist()");
    return;
  }

  msg_start();
  msg_row = Rows - 1;   // for when 'cmdheight' > 1
  lines_left = Rows;    // avoid more prompt
  msg_scroll = true;
  msg_clr_eos();

  TV_LIST_ITER_CONST(argvars[0].vval.v_list, li, {
    msg_puts(tv_get_string(TV_LIST_ITEM_TV(li)));
    msg_putchar('\n');
  });

  // Ask for choice.
  int mouse_used;
  int selected = prompt_for_number(&mouse_used);
  if (mouse_used) {
    selected -= lines_left;
  }

  rettv->vval.v_number = selected;
}

static garray_T ga_userinput = { 0, 0, sizeof(tasave_T), 4, NULL };

/// "inputrestore()" function
static void f_inputrestore(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (!GA_EMPTY(&ga_userinput)) {
    ga_userinput.ga_len--;
    restore_typeahead((tasave_T *)(ga_userinput.ga_data)
                      + ga_userinput.ga_len);
    // default return is zero == OK
  } else if (p_verbose > 1) {
    verb_msg(_("called inputrestore() more often than inputsave()"));
    rettv->vval.v_number = 1;  // Failed
  }
}

/// "inputsave()" function
static void f_inputsave(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // Add an entry to the stack of typeahead storage.
  tasave_T *p = GA_APPEND_VIA_PTR(tasave_T, &ga_userinput);
  save_typeahead(p);
}

/// "inputsecret()" function
static void f_inputsecret(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  cmdline_star++;
  inputsecret_flag = true;
  f_input(argvars, rettv, fptr);
  cmdline_star--;
  inputsecret_flag = false;
}

/// "insert()" function
static void f_insert(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  list_T *l;
  bool error = false;

  if (argvars[0].v_type == VAR_BLOB) {
    blob_T *const b = argvars[0].vval.v_blob;

    if (b == NULL
        || var_check_lock(b->bv_lock, N_("insert() argument"),
                          TV_TRANSLATE)) {
      return;
    }

    long before = 0;
    const int len = tv_blob_len(b);

    if (argvars[2].v_type != VAR_UNKNOWN) {
      before = (long)tv_get_number_chk(&argvars[2], &error);
      if (error) {
        return;  // type error; errmsg already given
      }
      if (before < 0 || before > len) {
        semsg(_(e_invarg2), tv_get_string(&argvars[2]));
        return;
      }
    }
    const int val = (int)tv_get_number_chk(&argvars[1], &error);
    if (error) {
      return;
    }
    if (val < 0 || val > 255) {
      semsg(_(e_invarg2), tv_get_string(&argvars[1]));
      return;
    }

    ga_grow(&b->bv_ga, 1);
    char_u *const p = (char_u *)b->bv_ga.ga_data;
    memmove(p + before + 1, p + before, (size_t)(len - before));
    *(p + before) = (char_u)val;
    b->bv_ga.ga_len++;

    tv_copy(&argvars[0], rettv);
  } else if (argvars[0].v_type != VAR_LIST) {
    semsg(_(e_listblobarg), "insert()");
  } else if (!var_check_lock(tv_list_locked((l = argvars[0].vval.v_list)),
                             N_("insert() argument"), TV_TRANSLATE)) {
    long before = 0;
    if (argvars[2].v_type != VAR_UNKNOWN) {
      before = tv_get_number_chk(&argvars[2], &error);
    }
    if (error) {
      // type error; errmsg already given
      return;
    }

    listitem_T *item = NULL;
    if (before != tv_list_len(l)) {
      item = tv_list_find(l, (int)before);
      if (item == NULL) {
        semsg(_(e_listidx), (int64_t)before);
        l = NULL;
      }
    }
    if (l != NULL) {
      tv_list_insert_tv(l, &argvars[1], item);
      tv_copy(&argvars[0], rettv);
    }
  }
}

/// "interrupt()" function
static void f_interrupt(typval_T *argvars FUNC_ATTR_UNUSED, typval_T *rettv FUNC_ATTR_UNUSED,
                        EvalFuncData fptr FUNC_ATTR_UNUSED)
{
  got_int = true;
}

/// "invert(expr)" function
static void f_invert(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = ~tv_get_number_chk(&argvars[0], NULL);
}

/// "isdirectory()" function
static void f_isdirectory(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = os_isdir(tv_get_string(&argvars[0]));
}

/// "islocked()" function
static void f_islocked(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  lval_T lv;

  rettv->vval.v_number = -1;
  const char_u *const end = (char_u *)get_lval((char *)tv_get_string(&argvars[0]),
                                               NULL,
                                               &lv, false, false,
                                               GLV_NO_AUTOLOAD|GLV_READ_ONLY,
                                               FNE_CHECK_START);
  if (end != NULL && lv.ll_name != NULL) {
    if (*end != NUL) {
      semsg(_(e_trailing_arg), end);
    } else {
      if (lv.ll_tv == NULL) {
        dictitem_T *di = find_var(lv.ll_name, lv.ll_name_len, NULL, true);
        if (di != NULL) {
          // Consider a variable locked when:
          // 1. the variable itself is locked
          // 2. the value of the variable is locked.
          // 3. the List or Dict value is locked.
          rettv->vval.v_number = ((di->di_flags & DI_FLAGS_LOCK)
                                  || tv_islocked(&di->di_tv));
        }
      } else if (lv.ll_range) {
        emsg(_("E786: Range not allowed"));
      } else if (lv.ll_newkey != NULL) {
        semsg(_(e_dictkey), lv.ll_newkey);
      } else if (lv.ll_list != NULL) {
        // List item.
        rettv->vval.v_number = tv_islocked(TV_LIST_ITEM_TV(lv.ll_li));
      } else {
        // Dictionary item.
        rettv->vval.v_number = tv_islocked(&lv.ll_di->di_tv);
      }
    }
  }

  clear_lval(&lv);
}

/// "isinf()" function
static void f_isinf(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type == VAR_FLOAT
      && xisinf(argvars[0].vval.v_float)) {
    rettv->vval.v_number = argvars[0].vval.v_float > 0.0 ? 1 : -1;
  }
}

/// "isnan()" function
static void f_isnan(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = argvars[0].v_type == VAR_FLOAT
                         && xisnan(argvars[0].vval.v_float);
}

/// "id()" function
static void f_id(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  const int len = vim_vsnprintf_typval(NULL, 0, "%p", dummy_ap, argvars);
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xmalloc((size_t)len + 1);
  vim_vsnprintf_typval(rettv->vval.v_string, (size_t)len + 1, "%p", dummy_ap, argvars);
}

/// "jobpid(id)" function
static void f_jobpid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER) {
    emsg(_(e_invarg));
    return;
  }

  Channel *data = find_job((uint64_t)argvars[0].vval.v_number, true);
  if (!data) {
    return;
  }

  Process *proc = &data->stream.proc;
  rettv->vval.v_number = proc->pid;
}

/// "jobresize(job, width, height)" function
static void f_jobresize(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER || argvars[1].v_type != VAR_NUMBER
      || argvars[2].v_type != VAR_NUMBER) {
    // job id, width, height
    emsg(_(e_invarg));
    return;
  }

  Channel *data = find_job((uint64_t)argvars[0].vval.v_number, true);
  if (!data) {
    return;
  }

  if (data->stream.proc.type != kProcessTypePty) {
    emsg(_(e_channotpty));
    return;
  }

  pty_process_resize(&data->stream.pty, (uint16_t)argvars[1].vval.v_number,
                     (uint16_t)argvars[2].vval.v_number);
  rettv->vval.v_number = 1;
}

static const char *ignored_env_vars[] = {
#ifndef MSWIN
  "COLUMNS",
  "LINES",
  "TERMCAP",
  "COLORFGBG",
#endif
  NULL
};

/// According to comments in src/win/process.c of libuv, Windows has a few
/// "essential" environment variables.
static const char *required_env_vars[] = {
#ifdef MSWIN
  "HOMEDRIVE",
  "HOMEPATH",
  "LOGONSERVER",
  "PATH",
  "SYSTEMDRIVE",
  "SYSTEMROOT",
  "TEMP",
  "USERDOMAIN",
  "USERNAME",
  "USERPROFILE",
  "WINDIR",
#endif
  NULL
};

static dict_T *create_environment(const dictitem_T *job_env, const bool clear_env, const bool pty,
                                  const char * const pty_term_name)
{
  dict_T *env = tv_dict_alloc();

  if (!clear_env) {
    typval_T temp_env = TV_INITIAL_VALUE;
    f_environ(NULL, &temp_env, (EvalFuncData){ .nullptr = NULL });
    tv_dict_extend(env, temp_env.vval.v_dict, "force");
    tv_dict_free(temp_env.vval.v_dict);

    if (pty) {
      // These environment variables generally shouldn't be propagated to the
      // child process.  We're removing them here so the user can still decide
      // they want to explicitly set them.
      for (size_t i = 0;
           i < ARRAY_SIZE(ignored_env_vars) && ignored_env_vars[i];
           i++) {
        dictitem_T *dv = tv_dict_find(env, ignored_env_vars[i], -1);
        if (dv) {
          tv_dict_item_remove(env, dv);
        }
      }
#ifndef MSWIN
      // Set COLORTERM to "truecolor" if termguicolors is set and 256
      // otherwise, but only if it was set in the parent terminal at all
      dictitem_T *dv = tv_dict_find(env, S_LEN("COLORTERM"));
      if (dv) {
        tv_dict_item_remove(env, dv);
        tv_dict_add_str(env, S_LEN("COLORTERM"), p_tgc ? "truecolor" : "256");
      }
#endif
    }
  }

  // For a pty, we need a sane $TERM set.  We can't rely on nvim's environment,
  // because the child process is going to be communicating with nvim, not the
  // parent terminal.  Set a sane default, but let the user override it in the
  // job's environment if they want.
  if (pty) {
    dictitem_T *dv = tv_dict_find(env, S_LEN("TERM"));
    if (dv) {
      tv_dict_item_remove(env, dv);
    }
    tv_dict_add_str(env, S_LEN("TERM"), pty_term_name);
  }

  // Set $NVIM (in the child process) to v:servername. #3118
  char *nvim_addr = get_vim_var_str(VV_SEND_SERVER);
  if (nvim_addr[0] != '\0') {
    dictitem_T *dv = tv_dict_find(env, S_LEN("NVIM"));
    if (dv) {
      tv_dict_item_remove(env, dv);
    }
    tv_dict_add_str(env, S_LEN("NVIM"), nvim_addr);
  }

  if (job_env) {
#ifdef MSWIN
    TV_DICT_ITER(job_env->di_tv.vval.v_dict, var, {
      // Always use upper-case keys for Windows so we detect duplicate keys
      char *const key = strcase_save((const char *)var->di_key, true);
      size_t len = strlen(key);
      dictitem_T *dv = tv_dict_find(env, key, len);
      if (dv) {
        tv_dict_item_remove(env, dv);
      }
      tv_dict_add_str(env, key, len, tv_get_string(&var->di_tv));
      xfree(key);
    });
#else
    tv_dict_extend(env, job_env->di_tv.vval.v_dict, "force");
#endif
  }

  if (pty) {
    // Now that the custom environment is configured, we need to ensure certain
    // environment variables are present.
    for (size_t i = 0;
         i < ARRAY_SIZE(required_env_vars) && required_env_vars[i];
         i++) {
      size_t len = strlen(required_env_vars[i]);
      dictitem_T *dv = tv_dict_find(env, required_env_vars[i], (ptrdiff_t)len);
      if (!dv) {
        const char *env_var = os_getenv(required_env_vars[i]);
        if (env_var) {
          tv_dict_add_str(env, required_env_vars[i], len, env_var);
        }
      }
    }
  }

  return env;
}

/// "jobstart()" function
static void f_jobstart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  bool executable = true;
  char **argv = tv_to_argv(&argvars[0], NULL, &executable);
  dict_T *env = NULL;
  if (!argv) {
    rettv->vval.v_number = executable ? 0 : -1;
    return;  // Did error message in tv_to_argv.
  }

  if (argvars[1].v_type != VAR_DICT && argvars[1].v_type != VAR_UNKNOWN) {
    // Wrong argument types
    semsg(_(e_invarg2), "expected dictionary");
    shell_free_argv(argv);
    return;
  }

  dict_T *job_opts = NULL;
  bool detach = false;
  bool rpc = false;
  bool pty = false;
  bool clear_env = false;
  bool overlapped = false;
  ChannelStdinMode stdin_mode = kChannelStdinPipe;
  CallbackReader on_stdout = CALLBACK_READER_INIT,
                 on_stderr = CALLBACK_READER_INIT;
  Callback on_exit = CALLBACK_NONE;
  char *cwd = NULL;
  dictitem_T *job_env = NULL;
  if (argvars[1].v_type == VAR_DICT) {
    job_opts = argvars[1].vval.v_dict;

    detach = tv_dict_get_number(job_opts, "detach") != 0;
    rpc = tv_dict_get_number(job_opts, "rpc") != 0;
    pty = tv_dict_get_number(job_opts, "pty") != 0;
    clear_env = tv_dict_get_number(job_opts, "clear_env") != 0;
    overlapped = tv_dict_get_number(job_opts, "overlapped") != 0;

    char *s = tv_dict_get_string(job_opts, "stdin", false);
    if (s) {
      if (!strncmp(s, "null", NUMBUFLEN)) {
        stdin_mode = kChannelStdinNull;
      } else if (!strncmp(s, "pipe", NUMBUFLEN)) {
        // Nothing to do, default value
      } else {
        semsg(_(e_invargNval), "stdin", s);
      }
    }

    if (pty && rpc) {
      semsg(_(e_invarg2), "job cannot have both 'pty' and 'rpc' options set");
      shell_free_argv(argv);
      return;
    }

#ifdef MSWIN
    if (pty && overlapped) {
      semsg(_(e_invarg2),
            "job cannot have both 'pty' and 'overlapped' options set");
      shell_free_argv(argv);
      return;
    }
#endif

    char *new_cwd = tv_dict_get_string(job_opts, "cwd", false);
    if (new_cwd && *new_cwd != NUL) {
      cwd = new_cwd;
      // The new cwd must be a directory.
      if (!os_isdir(cwd)) {
        semsg(_(e_invarg2), "expected valid directory");
        shell_free_argv(argv);
        return;
      }
    }

    job_env = tv_dict_find(job_opts, S_LEN("env"));
    if (job_env && job_env->di_tv.v_type != VAR_DICT) {
      semsg(_(e_invarg2), "env");
      shell_free_argv(argv);
      return;
    }

    if (!common_job_callbacks(job_opts, &on_stdout, &on_stderr, &on_exit)) {
      shell_free_argv(argv);
      return;
    }
  }

  uint16_t width = 0, height = 0;
  char *term_name = NULL;

  if (pty) {
    width = (uint16_t)tv_dict_get_number(job_opts, "width");
    height = (uint16_t)tv_dict_get_number(job_opts, "height");
    // Legacy method, before env option existed, to specify $TERM.  No longer
    // documented, but still usable to avoid breaking scripts.
    term_name = tv_dict_get_string(job_opts, "TERM", false);
    if (!term_name) {
      term_name = "ansi";
    }
  }

  env = create_environment(job_env, clear_env, pty, term_name);

  Channel *chan = channel_job_start(argv, on_stdout, on_stderr, on_exit, pty,
                                    rpc, overlapped, detach, stdin_mode, cwd,
                                    width, height, env, &rettv->vval.v_number);
  if (chan) {
    channel_create_event(chan, NULL);
  }
}

/// "jobstop()" function
static void f_jobstop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER) {
    // Only argument is the job id
    emsg(_(e_invarg));
    return;
  }

  Channel *data = find_job((uint64_t)argvars[0].vval.v_number, false);
  if (!data) {
    return;
  }

  const char *error = NULL;
  if (data->is_rpc) {
    // Ignore return code, but show error later.
    (void)channel_close(data->id, kChannelPartRpc, &error);
  }
  process_stop(&data->stream.proc);
  rettv->vval.v_number = 1;
  if (error) {
    emsg(error);
  }
}

/// "jobwait(ids[, timeout])" function
static void f_jobwait(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }
  if (argvars[0].v_type != VAR_LIST || (argvars[1].v_type != VAR_NUMBER
                                        && argvars[1].v_type != VAR_UNKNOWN)) {
    emsg(_(e_invarg));
    return;
  }

  ui_busy_start();
  list_T *args = argvars[0].vval.v_list;
  Channel **jobs = xcalloc((size_t)tv_list_len(args), sizeof(*jobs));
  MultiQueue *waiting_jobs = multiqueue_new_parent(loop_on_put, &main_loop);

  // Validate, prepare jobs for waiting.
  int i = 0;
  TV_LIST_ITER_CONST(args, arg, {
    Channel *chan = NULL;
    if (TV_LIST_ITEM_TV(arg)->v_type != VAR_NUMBER
        || !(chan = find_channel((uint64_t)TV_LIST_ITEM_TV(arg)->vval.v_number))
        || chan->streamtype != kChannelStreamProc) {
      jobs[i] = NULL;  // Invalid job.
    } else if (process_is_stopped(&chan->stream.proc)) {
      // Job is stopped but not fully destroyed.
      // Ensure all callbacks on its event queue are executed. #15402
      process_wait(&chan->stream.proc, -1, NULL);
      jobs[i] = NULL;  // Invalid job.
    } else {
      jobs[i] = chan;
      channel_incref(chan);
      if (chan->stream.proc.status < 0) {
        // Flush any events in the job's queue before temporarily replacing it.
        multiqueue_process_events(chan->events);
        multiqueue_replace_parent(chan->events, waiting_jobs);
      }
    }
    i++;
  });

  int remaining = -1;
  uint64_t before = 0;
  if (argvars[1].v_type == VAR_NUMBER && argvars[1].vval.v_number >= 0) {
    remaining = (int)argvars[1].vval.v_number;
    before = os_hrtime();
  }

  for (i = 0; i < tv_list_len(args); i++) {
    if (remaining == 0) {
      break;  // Timeout.
    }
    if (jobs[i] == NULL) {
      continue;  // Invalid job, will assign status=-3 below.
    }
    int status = process_wait(&jobs[i]->stream.proc, remaining,
                              waiting_jobs);
    if (status < 0) {
      break;  // Interrupted (CTRL-C) or timeout, skip remaining jobs.
    }
    if (remaining > 0) {
      uint64_t now = os_hrtime();
      remaining = MIN(0, remaining - (int)((now - before) / 1000000));
      before = now;
    }
  }

  list_T *const rv = tv_list_alloc(tv_list_len(args));

  // For each job:
  //  * Restore its parent queue if the job is still alive.
  //  * Append its status to the output list, or:
  //       -3 for "invalid job id"
  //       -2 for "interrupted" (user hit CTRL-C)
  //       -1 for jobs that were skipped or timed out
  for (i = 0; i < tv_list_len(args); i++) {
    if (jobs[i] == NULL) {
      tv_list_append_number(rv, -3);
      continue;
    }
    multiqueue_process_events(jobs[i]->events);
    multiqueue_replace_parent(jobs[i]->events, main_loop.events);

    tv_list_append_number(rv, jobs[i]->stream.proc.status);
    channel_decref(jobs[i]);
  }

  multiqueue_free(waiting_jobs);
  xfree(jobs);
  ui_busy_stop();
  tv_list_ref(rv);
  rettv->v_type = VAR_LIST;
  rettv->vval.v_list = rv;
}

/// json_decode() function
static void f_json_decode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char numbuf[NUMBUFLEN];
  const char *s = NULL;
  char *tofree = NULL;
  size_t len;
  if (argvars[0].v_type == VAR_LIST) {
    if (!encode_vim_list_to_buf(argvars[0].vval.v_list, &len, &tofree)) {
      emsg(_("E474: Failed to convert list to string"));
      return;
    }
    s = tofree;
    if (s == NULL) {
      assert(len == 0);
      s = "";
    }
  } else {
    s = tv_get_string_buf_chk(&argvars[0], numbuf);
    if (s) {
      len = strlen(s);
    } else {
      return;
    }
  }
  if (json_decode_string(s, len, rettv) == FAIL) {
    semsg(_("E474: Failed to parse %.*s"), (int)len, s);
    rettv->v_type = VAR_NUMBER;
    rettv->vval.v_number = 0;
  }
  assert(rettv->v_type != VAR_UNKNOWN);
  xfree(tofree);
}

/// json_encode() function
static void f_json_encode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = encode_tv2json(&argvars[0], NULL);
}

/// "keytrans()" function
static void f_keytrans(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  if (tv_check_for_string_arg(argvars, 0) == FAIL
      || argvars[0].vval.v_string == NULL) {
    return;
  }
  // Need to escape K_SPECIAL for mb_unescape().
  char *escaped = vim_strsave_escape_ks(argvars[0].vval.v_string);
  rettv->vval.v_string = str2special_save(escaped, true, true);
  xfree(escaped);
}

/// "last_buffer_nr()" function.
static void f_last_buffer_nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int n = 0;

  FOR_ALL_BUFFERS(buf) {
    if (n < buf->b_fnum) {
      n = buf->b_fnum;
    }
  }

  rettv->vval.v_number = n;
}

/// "len()" function
static void f_len(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  switch (argvars[0].v_type) {
  case VAR_STRING:
  case VAR_NUMBER:
    rettv->vval.v_number = (varnumber_T)strlen(tv_get_string(&argvars[0]));
    break;
  case VAR_BLOB:
    rettv->vval.v_number = tv_blob_len(argvars[0].vval.v_blob);
    break;
  case VAR_LIST:
    rettv->vval.v_number = tv_list_len(argvars[0].vval.v_list);
    break;
  case VAR_DICT:
    rettv->vval.v_number = tv_dict_len(argvars[0].vval.v_dict);
    break;
  case VAR_UNKNOWN:
  case VAR_BOOL:
  case VAR_SPECIAL:
  case VAR_FLOAT:
  case VAR_PARTIAL:
  case VAR_FUNC:
    emsg(_("E701: Invalid type for len()"));
    break;
  }
}

static void libcall_common(typval_T *argvars, typval_T *rettv, int out_type)
{
  rettv->v_type = (VarType)out_type;
  if (out_type != VAR_NUMBER) {
    rettv->vval.v_string = NULL;
  }

  if (check_secure()) {
    return;
  }

  // The first two args (libname and funcname) must be strings
  if (argvars[0].v_type != VAR_STRING || argvars[1].v_type != VAR_STRING) {
    return;
  }

  const char *libname = argvars[0].vval.v_string;
  const char *funcname = argvars[1].vval.v_string;

  VarType in_type = argvars[2].v_type;

  // input variables
  char *str_in = (in_type == VAR_STRING) ? argvars[2].vval.v_string : NULL;
  int int_in = (int)argvars[2].vval.v_number;

  // output variables
  char **str_out = (out_type == VAR_STRING) ? &rettv->vval.v_string : NULL;
  int int_out = 0;

  bool success = os_libcall(libname, funcname,
                            str_in, int_in,
                            str_out, &int_out);

  if (!success) {
    semsg(_(e_libcall), funcname);
    return;
  }

  if (out_type == VAR_NUMBER) {
    rettv->vval.v_number = (varnumber_T)int_out;
  }
}

/// "libcall()" function
static void f_libcall(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  libcall_common(argvars, rettv, VAR_STRING);
}

/// "libcallnr()" function
static void f_libcallnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  libcall_common(argvars, rettv, VAR_NUMBER);
}

/// "line(string, [winid])" function
static void f_line(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  linenr_T lnum = 0;
  pos_T *fp = NULL;
  int fnum;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    // use window specified in the second argument
    int id = (int)tv_get_number(&argvars[1]);
    tabpage_T *tp;
    win_T *wp = win_id2wp_tp(id, &tp);
    if (wp != NULL && tp != NULL) {
      switchwin_T switchwin;
      if (switch_win_noblock(&switchwin, wp, tp, true) == OK) {
        check_cursor();
        fp = var2fpos(&argvars[0], true, &fnum, false);
      }
      restore_win_noblock(&switchwin, true);
    }
  } else {
    // use current window
    fp = var2fpos(&argvars[0], true, &fnum, false);
  }

  if (fp != NULL) {
    lnum = fp->lnum;
  }
  rettv->vval.v_number = lnum;
}

/// "line2byte(lnum)" function
static void f_line2byte(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const linenr_T lnum = tv_get_lnum(argvars);
  if (lnum < 1 || lnum > curbuf->b_ml.ml_line_count + 1) {
    rettv->vval.v_number = -1;
  } else {
    rettv->vval.v_number = ml_find_line_or_offset(curbuf, lnum, NULL, false);
  }
  if (rettv->vval.v_number >= 0) {
    rettv->vval.v_number++;
  }
}

/// "lispindent(lnum)" function
static void f_lispindent(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const pos_T pos = curwin->w_cursor;
  const linenr_T lnum = tv_get_lnum(argvars);
  if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count) {
    curwin->w_cursor.lnum = lnum;
    rettv->vval.v_number = get_lisp_indent();
    curwin->w_cursor = pos;
  } else {
    rettv->vval.v_number = -1;
  }
}

/// "localtime()" function
static void f_localtime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = (varnumber_T)time(NULL);
}

/// luaeval() function implementation
static void f_luaeval(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  const char *const str = tv_get_string_chk(&argvars[0]);
  if (str == NULL) {
    return;
  }

  nlua_typval_eval(cstr_as_string((char *)str), &argvars[1], rettv);
}

/// "map()" function
static void f_map(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  filter_map(argvars, rettv, true);
}

static void find_some_match(typval_T *const argvars, typval_T *const rettv,
                            const SomeMatchType type)
{
  char *str = NULL;
  long len = 0;
  char *expr = NULL;
  regmatch_T regmatch;
  long start = 0;
  long nth = 1;
  colnr_T startcol = 0;
  bool match = false;
  list_T *l = NULL;
  long idx = 0;
  char *tofree = NULL;

  // Make 'cpoptions' empty, the 'l' flag should not be used here.
  char *save_cpo = p_cpo;
  p_cpo = empty_option;

  rettv->vval.v_number = -1;
  switch (type) {
  // matchlist(): return empty list when there are no matches.
  case kSomeMatchList:
    tv_list_alloc_ret(rettv, kListLenMayKnow);
    break;
  // matchstrpos(): return ["", -1, -1, -1]
  case kSomeMatchStrPos:
    tv_list_alloc_ret(rettv, 4);
    tv_list_append_string(rettv->vval.v_list, "", 0);
    tv_list_append_number(rettv->vval.v_list, -1);
    tv_list_append_number(rettv->vval.v_list, -1);
    tv_list_append_number(rettv->vval.v_list, -1);
    break;
  case kSomeMatchStr:
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = NULL;
    break;
  case kSomeMatch:
  case kSomeMatchEnd:
    // Do nothing: zero is default.
    break;
  }

  listitem_T *li = NULL;
  if (argvars[0].v_type == VAR_LIST) {
    if ((l = argvars[0].vval.v_list) == NULL) {
      goto theend;
    }
    li = tv_list_first(l);
  } else {
    expr = str = (char *)tv_get_string(&argvars[0]);
    len = (long)strlen(str);
  }

  char patbuf[NUMBUFLEN];
  const char *const pat = tv_get_string_buf_chk(&argvars[1], patbuf);
  if (pat == NULL) {
    goto theend;
  }

  if (argvars[2].v_type != VAR_UNKNOWN) {
    bool error = false;

    start = tv_get_number_chk(&argvars[2], &error);
    if (error) {
      goto theend;
    }
    if (l != NULL) {
      idx = tv_list_uidx(l, (int)start);
      if (idx == -1) {
        goto theend;
      }
      li = tv_list_find(l, (int)idx);
    } else {
      if (start < 0) {
        start = 0;
      }
      if (start > len) {
        goto theend;
      }
      // When "count" argument is there ignore matches before "start",
      // otherwise skip part of the string.  Differs when pattern is "^"
      // or "\<".
      if (argvars[3].v_type != VAR_UNKNOWN) {
        startcol = (colnr_T)start;
      } else {
        str += start;
        len -= start;
      }
    }

    if (argvars[3].v_type != VAR_UNKNOWN) {
      nth = tv_get_number_chk(&argvars[3], &error);
    }
    if (error) {
      goto theend;
    }
  }

  regmatch.regprog = vim_regcomp((char *)pat, RE_MAGIC + RE_STRING);
  if (regmatch.regprog != NULL) {
    regmatch.rm_ic = p_ic;

    for (;;) {
      if (l != NULL) {
        if (li == NULL) {
          match = false;
          break;
        }
        xfree(tofree);
        tofree = expr = str = encode_tv2echo(TV_LIST_ITEM_TV(li), NULL);
        if (str == NULL) {
          break;
        }
      }

      match = vim_regexec_nl(&regmatch, (char_u *)str, startcol);

      if (match && --nth <= 0) {
        break;
      }
      if (l == NULL && !match) {
        break;
      }

      // Advance to just after the match.
      if (l != NULL) {
        li = TV_LIST_ITEM_NEXT(l, li);
        idx++;
      } else {
        startcol = (colnr_T)(regmatch.startp[0]
                             + utfc_ptr2len(regmatch.startp[0]) - str);
        if (startcol > (colnr_T)len || str + startcol <= regmatch.startp[0]) {
          match = false;
          break;
        }
      }
    }

    if (match) {
      switch (type) {
      case kSomeMatchStrPos: {
        list_T *const ret_l = rettv->vval.v_list;
        listitem_T *li1 = tv_list_first(ret_l);
        listitem_T *li2 = TV_LIST_ITEM_NEXT(ret_l, li1);
        listitem_T *li3 = TV_LIST_ITEM_NEXT(ret_l, li2);
        listitem_T *li4 = TV_LIST_ITEM_NEXT(ret_l, li3);
        xfree(TV_LIST_ITEM_TV(li1)->vval.v_string);

        const size_t rd = (size_t)(regmatch.endp[0] - regmatch.startp[0]);
        TV_LIST_ITEM_TV(li1)->vval.v_string = xmemdupz(regmatch.startp[0], rd);
        TV_LIST_ITEM_TV(li3)->vval.v_number = (varnumber_T)(regmatch.startp[0] - expr);
        TV_LIST_ITEM_TV(li4)->vval.v_number = (varnumber_T)(regmatch.endp[0] - expr);
        if (l != NULL) {
          TV_LIST_ITEM_TV(li2)->vval.v_number = (varnumber_T)idx;
        }
        break;
      }
      case kSomeMatchList:
        // Return list with matched string and submatches.
        for (int i = 0; i < NSUBEXP; i++) {
          if (regmatch.endp[i] == NULL) {
            tv_list_append_string(rettv->vval.v_list, NULL, 0);
          } else {
            tv_list_append_string(rettv->vval.v_list,
                                  (const char *)regmatch.startp[i],
                                  (regmatch.endp[i] - regmatch.startp[i]));
          }
        }
        break;
      case kSomeMatchStr:
        // Return matched string.
        if (l != NULL) {
          tv_copy(TV_LIST_ITEM_TV(li), rettv);
        } else {
          rettv->vval.v_string = xmemdupz((const char *)regmatch.startp[0],
                                          (size_t)(regmatch.endp[0] -
                                                   regmatch.startp[0]));
        }
        break;
      case kSomeMatch:
      case kSomeMatchEnd:
        if (l != NULL) {
          rettv->vval.v_number = idx;
        } else {
          if (type == kSomeMatch) {
            rettv->vval.v_number = (varnumber_T)(regmatch.startp[0] - str);
          } else {
            rettv->vval.v_number = (varnumber_T)(regmatch.endp[0] - str);
          }
          rettv->vval.v_number += (varnumber_T)(str - expr);
        }
        break;
      }
    }
    vim_regfree(regmatch.regprog);
  }

theend:
  if (type == kSomeMatchStrPos && l == NULL && rettv->vval.v_list != NULL) {
    // matchstrpos() without a list: drop the second item
    list_T *const ret_l = rettv->vval.v_list;
    tv_list_item_remove(ret_l, TV_LIST_ITEM_NEXT(ret_l, tv_list_first(ret_l)));
  }

  xfree(tofree);
  p_cpo = save_cpo;
}

/// "match()" function
static void f_match(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  find_some_match(argvars, rettv, kSomeMatch);
}

/// "matchend()" function
static void f_matchend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  find_some_match(argvars, rettv, kSomeMatchEnd);
}

/// "matchlist()" function
static void f_matchlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  find_some_match(argvars, rettv, kSomeMatchList);
}

/// "matchstr()" function
static void f_matchstr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  find_some_match(argvars, rettv, kSomeMatchStr);
}

/// "matchstrpos()" function
static void f_matchstrpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  find_some_match(argvars, rettv, kSomeMatchStrPos);
}

/// Get maximal/minimal number value in a list or dictionary
///
/// @param[in]  tv  List or dictionary to work with. If it contains something
///                 that is not an integer number (or cannot be coerced to
///                 it) error is given.
/// @param[out]  rettv  Location where result will be saved. Only assigns
///                     vval.v_number, type is not touched. Returns zero for
///                     empty lists/dictionaries.
/// @param[in]  domax  Determines whether maximal or minimal value is desired.
static void max_min(const typval_T *const tv, typval_T *const rettv, const bool domax)
  FUNC_ATTR_NONNULL_ALL
{
  bool error = false;

  rettv->vval.v_number = 0;
  varnumber_T n = (domax ? VARNUMBER_MIN : VARNUMBER_MAX);
  if (tv->v_type == VAR_LIST) {
    if (tv_list_len(tv->vval.v_list) == 0) {
      return;
    }
    TV_LIST_ITER_CONST(tv->vval.v_list, li, {
      const varnumber_T i = tv_get_number_chk(TV_LIST_ITEM_TV(li), &error);
      if (error) {
        return;  // type error; errmsg already given
      }
      if (domax ? i > n : i < n) {
        n = i;
      }
    });
  } else if (tv->v_type == VAR_DICT) {
    if (tv_dict_len(tv->vval.v_dict) == 0) {
      return;
    }
    TV_DICT_ITER(tv->vval.v_dict, di, {
      const varnumber_T i = tv_get_number_chk(&di->di_tv, &error);
      if (error) {
        return;  // type error; errmsg already given
      }
      if (domax ? i > n : i < n) {
        n = i;
      }
    });
  } else {
    semsg(_(e_listdictarg), domax ? "max()" : "min()");
    return;
  }

  rettv->vval.v_number = n;
}

/// "max()" function
static void f_max(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  max_min(argvars, rettv, true);
}

/// "min()" function
static void f_min(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  max_min(argvars, rettv, false);
}

/// "mkdir()" function
static void f_mkdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int prot = 0755;  // -V536

  rettv->vval.v_number = FAIL;
  if (check_secure()) {
    return;
  }

  char buf[NUMBUFLEN];
  const char *const dir = tv_get_string_buf(&argvars[0], buf);
  if (*dir == NUL) {
    return;
  }

  if (*path_tail(dir) == NUL) {
    // Remove trailing slashes.
    *path_tail_with_sep((char *)dir) = NUL;
  }

  if (argvars[1].v_type != VAR_UNKNOWN) {
    if (argvars[2].v_type != VAR_UNKNOWN) {
      prot = (int)tv_get_number_chk(&argvars[2], NULL);
      if (prot == -1) {
        return;
      }
    }
    if (strcmp(tv_get_string(&argvars[1]), "p") == 0) {
      char *failed_dir;
      int ret = os_mkdir_recurse(dir, prot, &failed_dir);
      if (ret != 0) {
        semsg(_(e_mkdir), failed_dir, os_strerror(ret));
        xfree(failed_dir);
        rettv->vval.v_number = FAIL;
        return;
      }
      rettv->vval.v_number = OK;
      return;
    }
  }
  rettv->vval.v_number = vim_mkdir_emsg(dir, prot);
}

/// "mode()" function
static void f_mode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf[MODE_MAX_LENGTH];

  get_mode(buf);

  // Clear out the minor mode when the argument is not a non-zero number or
  // non-empty string.
  if (!non_zero_arg(&argvars[0])) {
    buf[1] = NUL;
  }

  rettv->vval.v_string = xstrdup(buf);
  rettv->v_type = VAR_STRING;
}

/// "msgpackdump()" function
static void f_msgpackdump(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  if (argvars[0].v_type != VAR_LIST) {
    semsg(_(e_listarg), "msgpackdump()");
    return;
  }
  list_T *const list = argvars[0].vval.v_list;
  msgpack_packer *packer;
  if (argvars[1].v_type != VAR_UNKNOWN
      && strequal(tv_get_string(&argvars[1]), "B")) {
    tv_blob_alloc_ret(rettv);
    packer = msgpack_packer_new(rettv->vval.v_blob, &encode_blob_write);
  } else {
    packer = msgpack_packer_new(tv_list_alloc_ret(rettv, kListLenMayKnow),
                                &encode_list_write);
  }
  const char *const msg = _("msgpackdump() argument, index %i");
  // Assume that translation will not take more then 4 times more space
  char msgbuf[sizeof("msgpackdump() argument, index ") * 4 + NUMBUFLEN];
  int idx = 0;
  TV_LIST_ITER(list, li, {
    vim_snprintf(msgbuf, sizeof(msgbuf), (char *)msg, idx);
    idx++;
    if (encode_vim_to_msgpack(packer, TV_LIST_ITEM_TV(li), msgbuf) == FAIL) {
      break;
    }
  });
  msgpack_packer_free(packer);
}

static int msgpackparse_convert_item(const msgpack_object data, const msgpack_unpack_return result,
                                     list_T *const ret_list, const bool fail_if_incomplete)
  FUNC_ATTR_NONNULL_ALL
{
  switch (result) {
  case MSGPACK_UNPACK_PARSE_ERROR:
    semsg(_(e_invarg2), "Failed to parse msgpack string");
    return FAIL;
  case MSGPACK_UNPACK_NOMEM_ERROR:
    emsg(_(e_outofmem));
    return FAIL;
  case MSGPACK_UNPACK_CONTINUE:
    if (fail_if_incomplete) {
      semsg(_(e_invarg2), "Incomplete msgpack string");
      return FAIL;
    }
    return NOTDONE;
  case MSGPACK_UNPACK_SUCCESS: {
    typval_T tv = { .v_type = VAR_UNKNOWN };
    if (msgpack_to_vim(data, &tv) == FAIL) {
      semsg(_(e_invarg2), "Failed to convert msgpack string");
      return FAIL;
    }
    tv_list_append_owned_tv(ret_list, tv);
    return OK;
  }
  default:
    abort();
  }
}

static void msgpackparse_unpack_list(const list_T *const list, list_T *const ret_list)
  FUNC_ATTR_NONNULL_ARG(2)
{
  if (tv_list_len(list) == 0) {
    return;
  }
  if (TV_LIST_ITEM_TV(tv_list_first(list))->v_type != VAR_STRING) {
    semsg(_(e_invarg2), "List item is not a string");
    return;
  }
  ListReaderState lrstate = encode_init_lrstate(list);
  msgpack_unpacker *const unpacker = msgpack_unpacker_new(IOSIZE);
  if (unpacker == NULL) {
    emsg(_(e_outofmem));
    return;
  }
  msgpack_unpacked unpacked;
  msgpack_unpacked_init(&unpacked);
  do {
    if (!msgpack_unpacker_reserve_buffer(unpacker, IOSIZE)) {
      emsg(_(e_outofmem));
      goto end;
    }
    size_t read_bytes;
    const int rlret = encode_read_from_list(&lrstate, msgpack_unpacker_buffer(unpacker), IOSIZE,
                                            &read_bytes);
    if (rlret == FAIL) {
      semsg(_(e_invarg2), "List item is not a string");
      goto end;
    }
    msgpack_unpacker_buffer_consumed(unpacker, read_bytes);
    if (read_bytes == 0) {
      break;
    }
    while (unpacker->off < unpacker->used) {
      const msgpack_unpack_return result
        = msgpack_unpacker_next(unpacker, &unpacked);
      const int conv_result = msgpackparse_convert_item(unpacked.data, result,
                                                        ret_list, rlret == OK);
      if (conv_result == NOTDONE) {
        break;
      } else if (conv_result == FAIL) {
        goto end;
      }
    }
    if (rlret == OK) {
      break;
    }
  } while (true);

end:
  msgpack_unpacker_free(unpacker);
  msgpack_unpacked_destroy(&unpacked);
}

static void msgpackparse_unpack_blob(const blob_T *const blob, list_T *const ret_list)
  FUNC_ATTR_NONNULL_ARG(2)
{
  const int len = tv_blob_len(blob);
  if (len == 0) {
    return;
  }
  msgpack_unpacked unpacked;
  msgpack_unpacked_init(&unpacked);
  for (size_t offset = 0; offset < (size_t)len;) {
    const msgpack_unpack_return result
      = msgpack_unpack_next(&unpacked, blob->bv_ga.ga_data, (size_t)len, &offset);
    if (msgpackparse_convert_item(unpacked.data, result, ret_list, true)
        != OK) {
      break;
    }
  }

  msgpack_unpacked_destroy(&unpacked);
}

/// "msgpackparse" function
static void f_msgpackparse(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  if (argvars[0].v_type != VAR_LIST && argvars[0].v_type != VAR_BLOB) {
    semsg(_(e_listblobarg), "msgpackparse()");
    return;
  }
  list_T *const ret_list = tv_list_alloc_ret(rettv, kListLenMayKnow);
  if (argvars[0].v_type == VAR_LIST) {
    msgpackparse_unpack_list(argvars[0].vval.v_list, ret_list);
  } else {
    msgpackparse_unpack_blob(argvars[0].vval.v_blob, ret_list);
  }
}

/// "nextnonblank()" function
static void f_nextnonblank(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  linenr_T lnum;

  for (lnum = tv_get_lnum(argvars);; lnum++) {
    if (lnum < 0 || lnum > curbuf->b_ml.ml_line_count) {
      lnum = 0;
      break;
    }
    if (*skipwhite(ml_get(lnum)) != NUL) {
      break;
    }
  }
  rettv->vval.v_number = lnum;
}

/// "nr2char()" function
static void f_nr2char(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[1].v_type != VAR_UNKNOWN) {
    if (!tv_check_num(&argvars[1])) {
      return;
    }
  }

  bool error = false;
  const varnumber_T num = tv_get_number_chk(&argvars[0], &error);
  if (error) {
    return;
  }
  if (num < 0) {
    emsg(_("E5070: Character number must not be less than zero"));
    return;
  }
  if (num > INT_MAX) {
    semsg(_("E5071: Character number must not be greater than INT_MAX (%i)"),
          INT_MAX);
    return;
  }

  char buf[MB_MAXBYTES];
  const int len = utf_char2bytes((int)num, buf);

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xmemdupz(buf, (size_t)len);
}

/// "or(expr, expr)" function
static void f_or(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = tv_get_number_chk(&argvars[0], NULL)
                         | tv_get_number_chk(&argvars[1], NULL);
}

/// "pathshorten()" function
static void f_pathshorten(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int trim_len = 1;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    trim_len = (int)tv_get_number(&argvars[1]);
    if (trim_len < 1) {
      trim_len = 1;
    }
  }

  rettv->v_type = VAR_STRING;
  const char *p = tv_get_string_chk(&argvars[0]);
  if (p == NULL) {
    rettv->vval.v_string = NULL;
  } else {
    rettv->vval.v_string = xstrdup(p);
    shorten_dir_len((char_u *)rettv->vval.v_string, trim_len);
  }
}

/// "pow()" function
static void f_pow(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  float_T fx;
  float_T fy;

  rettv->v_type = VAR_FLOAT;
  if (tv_get_float_chk(argvars, &fx) && tv_get_float_chk(&argvars[1], &fy)) {
    rettv->vval.v_float = pow(fx, fy);
  } else {
    rettv->vval.v_float = 0.0;
  }
}

/// "prevnonblank()" function
static void f_prevnonblank(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  linenr_T lnum = tv_get_lnum(argvars);
  if (lnum < 1 || lnum > curbuf->b_ml.ml_line_count) {
    lnum = 0;
  } else {
    while (lnum >= 1 && *skipwhite(ml_get(lnum)) == NUL) {
      lnum--;
    }
  }
  rettv->vval.v_number = lnum;
}

/// "printf()" function
static void f_printf(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
  {
    int saved_did_emsg = did_emsg;

    // Get the required length, allocate the buffer and do it for real.
    did_emsg = false;
    char buf[NUMBUFLEN];
    const char *fmt = tv_get_string_buf(&argvars[0], buf);
    int len = vim_vsnprintf_typval(NULL, 0, fmt, dummy_ap, argvars + 1);
    if (!did_emsg) {
      char *s = xmalloc((size_t)len + 1);
      rettv->vval.v_string = s;
      (void)vim_vsnprintf_typval(s, (size_t)len + 1, fmt, dummy_ap, argvars + 1);
    }
    did_emsg |= saved_did_emsg;
  }
}

/// "prompt_setcallback({buffer}, {callback})" function
static void f_prompt_setcallback(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  Callback prompt_callback = { .type = kCallbackNone };

  if (check_secure()) {
    return;
  }
  buf_T *buf = tv_get_buf(&argvars[0], false);
  if (buf == NULL) {
    return;
  }

  if (argvars[1].v_type != VAR_STRING || *argvars[1].vval.v_string != NUL) {
    if (!callback_from_typval(&prompt_callback, &argvars[1])) {
      return;
    }
  }

  callback_free(&buf->b_prompt_callback);
  buf->b_prompt_callback = prompt_callback;
}

/// "prompt_setinterrupt({buffer}, {callback})" function
static void f_prompt_setinterrupt(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  Callback interrupt_callback = { .type = kCallbackNone };

  if (check_secure()) {
    return;
  }
  buf_T *buf = tv_get_buf(&argvars[0], false);
  if (buf == NULL) {
    return;
  }

  if (argvars[1].v_type != VAR_STRING || *argvars[1].vval.v_string != NUL) {
    if (!callback_from_typval(&interrupt_callback, &argvars[1])) {
      return;
    }
  }

  callback_free(&buf->b_prompt_interrupt);
  buf->b_prompt_interrupt= interrupt_callback;
}

/// "prompt_getprompt({buffer})" function
static void f_prompt_getprompt(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  // return an empty string by default, e.g. it's not a prompt buffer
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
  if (buf == NULL) {
    return;
  }

  if (!bt_prompt(buf)) {
    return;
  }

  rettv->vval.v_string = xstrdup(buf_prompt_text(buf));
}

/// "prompt_setprompt({buffer}, {text})" function
static void f_prompt_setprompt(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }
  buf_T *buf = tv_get_buf(&argvars[0], false);
  if (buf == NULL) {
    return;
  }

  const char *text = tv_get_string(&argvars[1]);
  xfree(buf->b_prompt_text);
  buf->b_prompt_text = xstrdup(text);
}

/// "pum_getpos()" function
static void f_pum_getpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);
  pum_set_event_info(rettv->vval.v_dict);
}

/// "pumvisible()" function
static void f_pumvisible(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (pum_visible()) {
    rettv->vval.v_number = 1;
  }
}

/// "py3eval()" and "pyxeval()" functions (always python3)
static void f_py3eval(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  script_host_eval("python3", argvars, rettv);
}

static void init_srand(uint32_t *const x)
  FUNC_ATTR_NONNULL_ALL
{
#ifndef MSWIN
  static int dev_urandom_state = NOTDONE;  // FAIL or OK once tried

  if (dev_urandom_state != FAIL) {
    const int fd = os_open("/dev/urandom", O_RDONLY, 0);
    struct {
      union {
        uint32_t number;
        char bytes[sizeof(uint32_t)];
      } contents;
    } buf;

    // Attempt reading /dev/urandom.
    if (fd == -1) {
      dev_urandom_state = FAIL;
    } else {
      buf.contents.number = 0;
      if (read(fd, buf.contents.bytes, sizeof(uint32_t)) != sizeof(uint32_t)) {
        dev_urandom_state = FAIL;
      } else {
        dev_urandom_state = OK;
        *x = buf.contents.number;
      }
      os_close(fd);
    }
  }
  if (dev_urandom_state != OK) {
    // Reading /dev/urandom doesn't work, fall back to os_hrtime() XOR with process ID
#endif
  // uncrustify:off
    *x = (uint32_t)os_hrtime();
    *x ^= (uint32_t)os_get_pid();
#ifndef MSWIN
  }
#endif
  // uncrustify:on
}

static inline uint32_t splitmix32(uint32_t *const x)
  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_ALWAYS_INLINE
{
  uint32_t z = (*x += 0x9e3779b9);
  z = (z ^ (z >> 16)) * 0x85ebca6b;
  z = (z ^ (z >> 13)) * 0xc2b2ae35;
  return z ^ (z >> 16);
}

static inline uint32_t shuffle_xoshiro128starstar(uint32_t *const x, uint32_t *const y,
                                                  uint32_t *const z, uint32_t *const w)
  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_ALWAYS_INLINE
{
#define ROTL(x, k) (((x) << (k)) | ((x) >> (32 - (k))))
  const uint32_t result = ROTL(*y * 5, 7) * 9;
  const uint32_t t = *y << 9;
  *z ^= *x;
  *w ^= *y;
  *y ^= *z;
  *x ^= *w;
  *z ^= t;
  *w = ROTL(*w, 11);
#undef ROTL
  return result;
}

/// "rand()" function
static void f_rand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  uint32_t result;

  if (argvars[0].v_type == VAR_UNKNOWN) {
    static uint32_t gx, gy, gz, gw;
    static bool initialized = false;

    // When no argument is given use the global seed list.
    if (!initialized) {
      // Initialize the global seed list.
      uint32_t x = 0;
      init_srand(&x);

      gx = splitmix32(&x);
      gy = splitmix32(&x);
      gz = splitmix32(&x);
      gw = splitmix32(&x);
      initialized = true;
    }

    result = shuffle_xoshiro128starstar(&gx, &gy, &gz, &gw);
  } else if (argvars[0].v_type == VAR_LIST) {
    list_T *const l = argvars[0].vval.v_list;
    if (tv_list_len(l) != 4) {
      goto theend;
    }

    typval_T *const tvx = TV_LIST_ITEM_TV(tv_list_find(l, 0L));
    typval_T *const tvy = TV_LIST_ITEM_TV(tv_list_find(l, 1L));
    typval_T *const tvz = TV_LIST_ITEM_TV(tv_list_find(l, 2L));
    typval_T *const tvw = TV_LIST_ITEM_TV(tv_list_find(l, 3L));
    if (tvx->v_type != VAR_NUMBER) {
      goto theend;
    }
    if (tvy->v_type != VAR_NUMBER) {
      goto theend;
    }
    if (tvz->v_type != VAR_NUMBER) {
      goto theend;
    }
    if (tvw->v_type != VAR_NUMBER) {
      goto theend;
    }
    uint32_t x = (uint32_t)tvx->vval.v_number;
    uint32_t y = (uint32_t)tvy->vval.v_number;
    uint32_t z = (uint32_t)tvz->vval.v_number;
    uint32_t w = (uint32_t)tvw->vval.v_number;

    result = shuffle_xoshiro128starstar(&x, &y, &z, &w);

    tvx->vval.v_number = (varnumber_T)x;
    tvy->vval.v_number = (varnumber_T)y;
    tvz->vval.v_number = (varnumber_T)z;
    tvw->vval.v_number = (varnumber_T)w;
  } else {
    goto theend;
  }

  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = (varnumber_T)result;
  return;

theend:
  semsg(_(e_invarg2), tv_get_string(&argvars[0]));
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = -1;
}

/// "srand()" function
static void f_srand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  uint32_t x = 0;

  tv_list_alloc_ret(rettv, 4);
  if (argvars[0].v_type == VAR_UNKNOWN) {
    init_srand(&x);
  } else {
    bool error = false;
    x = (uint32_t)tv_get_number_chk(&argvars[0], &error);
    if (error) {
      return;
    }
  }

  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)splitmix32(&x));
}

/// "perleval()" function
static void f_perleval(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  script_host_eval("perl", argvars, rettv);
}

/// "rubyeval()" function
static void f_rubyeval(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  script_host_eval("ruby", argvars, rettv);
}

/// "range()" function
static void f_range(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  varnumber_T end;
  varnumber_T stride = 1;
  bool error = false;

  varnumber_T start = tv_get_number_chk(&argvars[0], &error);
  if (argvars[1].v_type == VAR_UNKNOWN) {
    end = start - 1;
    start = 0;
  } else {
    end = tv_get_number_chk(&argvars[1], &error);
    if (argvars[2].v_type != VAR_UNKNOWN) {
      stride = tv_get_number_chk(&argvars[2], &error);
    }
  }

  if (error) {
    return;  // Type error; errmsg already given.
  }
  if (stride == 0) {
    emsg(_("E726: Stride is zero"));
    return;
  }
  if (stride > 0 ? end + 1 < start : end - 1 > start) {
    emsg(_("E727: Start past end"));
    return;
  }

  tv_list_alloc_ret(rettv, (end - start) / stride);
  for (varnumber_T i = start; stride > 0 ? i <= end : i >= end; i += stride) {
    tv_list_append_number(rettv->vval.v_list, i);
  }
}

/// Evaluate "expr" (= "context") for readdir().
static varnumber_T readdir_checkitem(void *context, const char *name)
  FUNC_ATTR_NONNULL_ALL
{
  typval_T *expr = (typval_T *)context;
  typval_T argv[2];
  varnumber_T retval = 0;
  bool error = false;

  if (expr->v_type == VAR_UNKNOWN) {
    return 1;
  }

  typval_T save_val;
  prepare_vimvar(VV_VAL, &save_val);
  set_vim_var_string(VV_VAL, name, -1);
  argv[0].v_type = VAR_STRING;
  argv[0].vval.v_string = (char *)name;

  typval_T rettv;
  if (eval_expr_typval(expr, argv, 1, &rettv) == FAIL) {
    goto theend;
  }

  retval = tv_get_number_chk(&rettv, &error);
  if (error) {
    retval = -1;
  }

  tv_clear(&rettv);

theend:
  set_vim_var_string(VV_VAL, NULL, 0);
  restore_vimvar(VV_VAL, &save_val);
  return retval;
}

/// "readdir()" function
static void f_readdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenUnknown);

  const char *path = tv_get_string(&argvars[0]);
  typval_T *expr = &argvars[1];
  garray_T ga;
  int ret = readdir_core(&ga, path, (void *)expr, readdir_checkitem);
  if (ret == OK && ga.ga_len > 0) {
    for (int i = 0; i < ga.ga_len; i++) {
      const char *p = ((const char **)ga.ga_data)[i];
      tv_list_append_string(rettv->vval.v_list, p, -1);
    }
  }
  ga_clear_strings(&ga);
}

/// "readfile()" or "readblob()" function
static void read_file_or_blob(typval_T *argvars, typval_T *rettv, bool always_blob)
{
  bool binary = false;
  bool blob = always_blob;
  FILE *fd;
  char buf[(IOSIZE/256) * 256];    // rounded to avoid odd + 1
  int io_size = sizeof(buf);
  char *prev = NULL;               // previously read bytes, if any
  ptrdiff_t prevlen  = 0;               // length of data in prev
  ptrdiff_t prevsize = 0;               // size of prev buffer
  long maxline  = MAXLNUM;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    if (strcmp(tv_get_string(&argvars[1]), "b") == 0) {
      binary = true;
    } else if (strcmp(tv_get_string(&argvars[1]), "B") == 0) {
      blob = true;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      maxline = tv_get_number(&argvars[2]);
    }
  }

  // Always open the file in binary mode, library functions have a mind of
  // their own about CR-LF conversion.
  const char *const fname = tv_get_string(&argvars[0]);

  if (os_isdir(fname)) {
    semsg(_(e_isadir2), fname);
    return;
  }
  if (*fname == NUL || (fd = os_fopen(fname, READBIN)) == NULL) {
    semsg(_(e_notopen), *fname == NUL ? _("<empty>") : fname);
    return;
  }

  if (blob) {
    tv_blob_alloc_ret(rettv);
    if (!read_blob(fd, rettv->vval.v_blob)) {
      semsg(_(e_notread), fname);
      // An empty blob is returned on error.
      tv_blob_free(rettv->vval.v_blob);
      rettv->vval.v_blob = NULL;
    }
    fclose(fd);
    return;
  }

  list_T *const l = tv_list_alloc_ret(rettv, kListLenUnknown);

  while (maxline < 0 || tv_list_len(l) < maxline) {
    int readlen = (int)fread(buf, 1, (size_t)io_size, fd);

    // This for loop processes what was read, but is also entered at end
    // of file so that either:
    // - an incomplete line gets written
    // - a "binary" file gets an empty line at the end if it ends in a
    //   newline.
    char *p;  // Position in buf.
    char *start;  // Start of current line.
    for (p = buf, start = buf;
         p < buf + readlen || (readlen <= 0 && (prevlen > 0 || binary));
         p++) {
      if (readlen <= 0 || *p == '\n') {
        char *s  = NULL;
        size_t len = (size_t)(p - start);

        // Finished a line.  Remove CRs before NL.
        if (readlen > 0 && !binary) {
          while (len > 0 && start[len - 1] == '\r') {
            len--;
          }
          // removal may cross back to the "prev" string
          if (len == 0) {
            while (prevlen > 0 && prev[prevlen - 1] == '\r') {
              prevlen--;
            }
          }
        }
        if (prevlen == 0) {
          assert(len < INT_MAX);
          s = xstrnsave(start, len);
        } else {
          // Change "prev" buffer to be the right size.  This way
          // the bytes are only copied once, and very long lines are
          // allocated only once.
          s = xrealloc(prev, (size_t)prevlen + len + 1);
          memcpy(s + prevlen, start, len);
          s[(size_t)prevlen + len] = NUL;
          prev = NULL;             // the list will own the string
          prevlen = prevsize = 0;
        }

        tv_list_append_owned_tv(l, (typval_T) {
          .v_type = VAR_STRING,
          .v_lock = VAR_UNLOCKED,
          .vval.v_string = s,
        });

        start = p + 1;  // Step over newline.
        if (maxline < 0) {
          if (tv_list_len(l) > -maxline) {
            assert(tv_list_len(l) == 1 + (-maxline));
            tv_list_item_remove(l, tv_list_first(l));
          }
        } else if (tv_list_len(l) >= maxline) {
          assert(tv_list_len(l) == maxline);
          break;
        }
        if (readlen <= 0) {
          break;
        }
      } else if (*p == NUL) {
        *p = '\n';
        // Check for utf8 "bom"; U+FEFF is encoded as EF BB BF.  Do this
        // when finding the BF and check the previous two bytes.
      } else if ((uint8_t)(*p) == 0xbf && !binary) {
        // Find the two bytes before the 0xbf.  If p is at buf, or buf + 1,
        // these may be in the "prev" string.
        char back1 = p >= buf + 1 ? p[-1]
                                    : prevlen >= 1 ? prev[prevlen - 1] : NUL;
        char back2 = p >= buf + 2 ? p[-2]
                                    : p == buf + 1 && prevlen >= 1 ? prev[prevlen - 1]
                                                                   : prevlen >=
                     2 ? prev[prevlen - 2] : NUL;

        if ((uint8_t)back2 == 0xef && (uint8_t)back1 == 0xbb) {
          char *dest = p - 2;

          // Usually a BOM is at the beginning of a file, and so at
          // the beginning of a line; then we can just step over it.
          if (start == dest) {
            start = p + 1;
          } else {
            // have to shuffle buf to close gap
            int adjust_prevlen = 0;

            if (dest < buf) {  // -V782
              // adjust_prevlen must be 1 or 2.
              adjust_prevlen = (int)(buf - dest);  // -V782
              dest = buf;
            }
            if (readlen > p - buf + 1) {
              memmove(dest, p + 1, (size_t)readlen - (size_t)(p - buf) - 1);
            }
            readlen -= 3 - adjust_prevlen;
            prevlen -= adjust_prevlen;
            p = dest - 1;
          }
        }
      }
    }     // for

    if ((maxline >= 0 && tv_list_len(l) >= maxline) || readlen <= 0) {
      break;
    }
    if (start < p) {
      // There's part of a line in buf, store it in "prev".
      if (p - start + prevlen >= prevsize) {
        // A common use case is ordinary text files and "prev" gets a
        // fragment of a line, so the first allocation is made
        // small, to avoid repeatedly 'allocing' large and
        // 'reallocing' small.
        if (prevsize == 0) {
          prevsize = p - start;
        } else {
          ptrdiff_t grow50pc = (prevsize * 3) / 2;
          ptrdiff_t growmin  = (p - start) * 2 + prevlen;
          prevsize = grow50pc > growmin ? grow50pc : growmin;
        }
        prev = xrealloc(prev, (size_t)prevsize);
      }
      // Add the line part to end of "prev".
      memmove(prev + prevlen, start, (size_t)(p - start));
      prevlen += p - start;
    }
  }   // while

  xfree(prev);
  fclose(fd);
}

/// "readblob()" function
static void f_readblob(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  read_file_or_blob(argvars, rettv, true);
}

/// "readfile()" function
static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  read_file_or_blob(argvars, rettv, false);
}

/// "getreginfo()" function
static void f_getreginfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int regname = getreg_get_regname(argvars);
  if (regname == 0) {
    return;
  }

  if (regname == '@') {
    regname = '"';
  }

  tv_dict_alloc_ret(rettv);
  dict_T *const dict = rettv->vval.v_dict;

  list_T *const list = get_reg_contents(regname, kGRegExprSrc | kGRegList);
  if (list == NULL) {
    return;
  }
  (void)tv_dict_add_list(dict, S_LEN("regcontents"), list);

  char buf[NUMBUFLEN + 2];
  buf[0] = NUL;
  buf[1] = NUL;
  colnr_T reglen = 0;
  switch (get_reg_type(regname, &reglen)) {
  case kMTLineWise:
    buf[0] = 'V';
    break;
  case kMTCharWise:
    buf[0] = 'v';
    break;
  case kMTBlockWise:
    vim_snprintf(buf, sizeof(buf), "%c%d", Ctrl_V, reglen + 1);
    break;
  case kMTUnknown:
    abort();
  }
  (void)tv_dict_add_str(dict, S_LEN("regtype"), buf);

  buf[0] = (char)get_register_name(get_unname_register());
  buf[1] = NUL;
  if (regname == '"') {
    (void)tv_dict_add_str(dict, S_LEN("points_to"), buf);
  } else {
    (void)tv_dict_add_bool(dict, S_LEN("isunnamed"),
                           regname == buf[0] ? kBoolVarTrue : kBoolVarFalse);
  }
}

/// "reg_executing()" function
static void f_reg_executing(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  return_register(reg_executing, rettv);
}

/// "reg_recording()" function
static void f_reg_recording(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  return_register(reg_recording, rettv);
}

static void f_reg_recorded(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  return_register(reg_recorded, rettv);
}

/// list2proftime - convert a List to proftime_T
///
/// @param arg The input list, must be of type VAR_LIST and have
///            exactly 2 items
/// @param[out] tm The proftime_T representation of `arg`
/// @return OK In case of success, FAIL in case of error
static int list2proftime(typval_T *arg, proftime_T *tm) FUNC_ATTR_NONNULL_ALL
{
  if (arg->v_type != VAR_LIST || tv_list_len(arg->vval.v_list) != 2) {
    return FAIL;
  }

  bool error = false;
  varnumber_T n1 = tv_list_find_nr(arg->vval.v_list, 0L, &error);
  varnumber_T n2 = tv_list_find_nr(arg->vval.v_list, 1L, &error);
  if (error) {
    return FAIL;
  }

  // in f_reltime() we split up the 64-bit proftime_T into two 32-bit
  // values, now we combine them again.
  union {
    struct { int32_t low, high; } split;
    proftime_T prof;
  } u = { .split.high = (int32_t)n1, .split.low = (int32_t)n2 };

  *tm = u.prof;

  return OK;
}

/// f_reltime - return an item that represents a time value
///
/// @param[out] rettv Without an argument it returns the current time. With
///             one argument it returns the time passed since the argument.
///             With two arguments it returns the time passed between
///             the two arguments.
static void f_reltime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  proftime_T res;
  proftime_T start;

  if (argvars[0].v_type == VAR_UNKNOWN) {
    // no arguments: get current time.
    res = profile_start();
  } else if (argvars[1].v_type == VAR_UNKNOWN) {
    if (list2proftime(&argvars[0], &res) == FAIL) {
      return;
    }
    res = profile_end(res);
  } else {
    // two arguments: compute the difference.
    if (list2proftime(&argvars[0], &start) == FAIL
        || list2proftime(&argvars[1], &res) == FAIL) {
      return;
    }
    res = profile_sub(res, start);
  }

  // we have to store the 64-bit proftime_T inside of a list of int's
  // (varnumber_T is defined as int). For all our supported platforms, int's
  // are at least 32-bits wide. So we'll use two 32-bit values to store it.
  union {
    struct { int32_t low, high; } split;
    proftime_T prof;
  } u = { .prof = res };

  // statically assert that the union type conv will provide the correct
  // results, if varnumber_T or proftime_T change, the union cast will need
  // to be revised.
  STATIC_ASSERT(sizeof(u.prof) == sizeof(u) && sizeof(u.split) == sizeof(u),
                "type punning will produce incorrect results on this platform");

  tv_list_alloc_ret(rettv, 2);
  tv_list_append_number(rettv->vval.v_list, u.split.high);
  tv_list_append_number(rettv->vval.v_list, u.split.low);
}

/// "reltimestr()" function
static void f_reltimestr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  proftime_T tm;

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
  if (list2proftime(&argvars[0], &tm) == OK) {
    rettv->vval.v_string = xstrdup(profile_msg(tm));
  }
}

/// "remove()" function
static void f_remove(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const arg_errmsg = N_("remove() argument");

  if (argvars[0].v_type == VAR_DICT) {
    tv_dict_remove(argvars, rettv, arg_errmsg);
  } else if (argvars[0].v_type == VAR_BLOB) {
    tv_blob_remove(argvars, rettv, arg_errmsg);
  } else if (argvars[0].v_type == VAR_LIST) {
    tv_list_remove(argvars, rettv, arg_errmsg);
  } else {
    semsg(_(e_listdictblobarg), "remove()");
  }
}

/// "rename({from}, {to})" function
static void f_rename(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    rettv->vval.v_number = -1;
  } else {
    char buf[NUMBUFLEN];
    rettv->vval.v_number = vim_rename(tv_get_string(&argvars[0]),
                                      tv_get_string_buf(&argvars[1], buf));
  }
}

/// "repeat()" function
static void f_repeat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  varnumber_T n = tv_get_number(&argvars[1]);
  if (argvars[0].v_type == VAR_LIST) {
    tv_list_alloc_ret(rettv, (n > 0) * n * tv_list_len(argvars[0].vval.v_list));
    while (n-- > 0) {
      tv_list_extend(rettv->vval.v_list, argvars[0].vval.v_list, NULL);
    }
  } else {
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = NULL;
    if (n <= 0) {
      return;
    }

    const char *const p = tv_get_string(&argvars[0]);

    const size_t slen = strlen(p);
    if (slen == 0) {
      return;
    }
    const size_t len = slen * (size_t)n;
    // Detect overflow.
    if (len / (size_t)n != slen) {
      return;
    }

    char *const r = xmallocz(len);
    for (varnumber_T i = 0; i < n; i++) {
      memmove(r + (size_t)i * slen, p, slen);
    }

    rettv->vval.v_string = r;
  }
}

/// "resolve()" function
static void f_resolve(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  const char *fname = tv_get_string(&argvars[0]);
#ifdef MSWIN
  char *v = os_resolve_shortcut(fname);
  if (v == NULL) {
    if (os_is_reparse_point_include(fname)) {
      v = os_realpath(fname, v);
    }
  }
  rettv->vval.v_string = (v == NULL ? xstrdup(fname) : v);
#else
# ifdef HAVE_READLINK
  {
    bool is_relative_to_current = false;
    bool has_trailing_pathsep = false;
    int limit = 100;

    char *p = xstrdup(fname);

    if (p[0] == '.' && (vim_ispathsep(p[1])
                        || (p[1] == '.' && (vim_ispathsep(p[2]))))) {
      is_relative_to_current = true;
    }

    ptrdiff_t len = (ptrdiff_t)strlen(p);
    if (len > 1 && after_pathsep(p, p + len)) {
      has_trailing_pathsep = true;
      p[len - 1] = NUL;  // The trailing slash breaks readlink().
    }

    char *q = (char *)path_next_component(p);
    char *remain = NULL;
    if (*q != NUL) {
      // Separate the first path component in "p", and keep the
      // remainder (beginning with the path separator).
      remain = xstrdup(q - 1);
      q[-1] = NUL;
    }

    char *const buf = xmallocz(MAXPATHL);

    char *cpy;
    for (;;) {
      for (;;) {
        len = readlink(p, buf, MAXPATHL);
        if (len <= 0) {
          break;
        }
        buf[len] = NUL;

        if (limit-- == 0) {
          xfree(p);
          xfree(remain);
          emsg(_("E655: Too many symbolic links (cycle?)"));
          rettv->vval.v_string = NULL;
          xfree(buf);
          return;
        }

        // Ensure that the result will have a trailing path separator
        // if the argument has one. */
        if (remain == NULL && has_trailing_pathsep) {
          add_pathsep(buf);
        }

        // Separate the first path component in the link value and
        // concatenate the remainders. */
        q = (char *)path_next_component(vim_ispathsep(*buf) ? buf + 1 : buf);
        if (*q != NUL) {
          cpy = remain;
          remain = (remain
                    ? concat_str(q - 1, remain)
                    : xstrdup(q - 1));
          xfree(cpy);
          q[-1] = NUL;
        }

        q = path_tail(p);
        if (q > p && *q == NUL) {
          // Ignore trailing path separator.
          q[-1] = NUL;
          q = path_tail(p);
        }
        if (q > p && !path_is_absolute((const char_u *)buf)) {
          // Symlink is relative to directory of argument. Replace the
          // symlink with the resolved name in the same directory.
          const size_t p_len = strlen(p);
          const size_t buf_len = strlen(buf);
          p = xrealloc(p, p_len + buf_len + 1);
          memcpy(path_tail(p), buf, buf_len + 1);
        } else {
          xfree(p);
          p = xstrdup(buf);
        }
      }

      if (remain == NULL) {
        break;
      }

      // Append the first path component of "remain" to "p".
      q = (char *)path_next_component(remain + 1);
      len = q - remain - (*q != NUL);
      const size_t p_len = strlen(p);
      cpy = xmallocz(p_len + (size_t)len);
      memcpy(cpy, p, p_len + 1);
      xstrlcat(cpy + p_len, remain, (size_t)len + 1);
      xfree(p);
      p = cpy;

      // Shorten "remain".
      if (*q != NUL) {
        STRMOVE(remain, q - 1);
      } else {
        XFREE_CLEAR(remain);
      }
    }

    // If the result is a relative path name, make it explicitly relative to
    // the current directory if and only if the argument had this form.
    if (!vim_ispathsep(*p)) {
      if (is_relative_to_current
          && *p != NUL
          && !(p[0] == '.'
               && (p[1] == NUL
                   || vim_ispathsep(p[1])
                   || (p[1] == '.'
                       && (p[2] == NUL
                           || vim_ispathsep(p[2])))))) {
        // Prepend "./".
        cpy = concat_str("./", p);
        xfree(p);
        p = cpy;
      } else if (!is_relative_to_current) {
        // Strip leading "./".
        q = p;
        while (q[0] == '.' && vim_ispathsep(q[1])) {
          q += 2;
        }
        if (q > p) {
          STRMOVE(p, p + 2);
        }
      }
    }

    // Ensure that the result will have no trailing path separator
    // if the argument had none.  But keep "/" or "//".
    if (!has_trailing_pathsep) {
      q = p + strlen(p);
      if (after_pathsep(p, q)) {
        *path_tail_with_sep(p) = NUL;
      }
    }

    rettv->vval.v_string = p;
    xfree(buf);
  }
# else
  char *v = os_realpath(fname, NULL);
  rettv->vval.v_string = (char_u *)(v == NULL ? xstrdup(fname) : v);
# endif
#endif

  simplify_filename((char_u *)rettv->vval.v_string);
}

/// "reverse({list})" function
static void f_reverse(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type == VAR_BLOB) {
    blob_T *const b = argvars[0].vval.v_blob;
    const int len = tv_blob_len(b);

    for (int i = 0; i < len / 2; i++) {
      const char_u tmp = tv_blob_get(b, i);
      tv_blob_set(b, i, tv_blob_get(b, len - i - 1));
      tv_blob_set(b, len - i - 1, tmp);
    }
    tv_blob_set_ret(rettv, b);
  } else if (argvars[0].v_type != VAR_LIST) {
    semsg(_(e_listblobarg), "reverse()");
  } else {
    list_T *const l = argvars[0].vval.v_list;
    if (!var_check_lock(tv_list_locked(l), N_("reverse() argument"),
                        TV_TRANSLATE)) {
      tv_list_reverse(l);
      tv_list_set_ret(rettv, l);
    }
  }
}

/// "reduce(list, { accumulator, element -> value } [, initial])" function
static void f_reduce(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_LIST && argvars[0].v_type != VAR_BLOB) {
    emsg(_(e_listblobreq));
    return;
  }

  const char *func_name;
  partial_T *partial = NULL;
  if (argvars[1].v_type == VAR_FUNC) {
    func_name = argvars[1].vval.v_string;
  } else if (argvars[1].v_type == VAR_PARTIAL) {
    partial = argvars[1].vval.v_partial;
    func_name = partial_name(partial);
  } else {
    func_name = tv_get_string(&argvars[1]);
  }
  if (*func_name == NUL) {
    return;  // type error or empty name
  }

  funcexe_T funcexe = FUNCEXE_INIT;
  funcexe.fe_evaluate = true;
  funcexe.fe_partial = partial;

  typval_T initial;
  typval_T argv[3];
  if (argvars[0].v_type == VAR_LIST) {
    list_T *const l = argvars[0].vval.v_list;
    const listitem_T *li;

    if (argvars[2].v_type == VAR_UNKNOWN) {
      if (tv_list_len(l) == 0) {
        semsg(_(e_reduceempty), "List");
        return;
      }
      const listitem_T *const first = tv_list_first(l);
      initial = *TV_LIST_ITEM_TV(first);
      li = TV_LIST_ITEM_NEXT(l, first);
    } else {
      initial = argvars[2];
      li = tv_list_first(l);
    }

    tv_copy(&initial, rettv);

    if (l != NULL) {
      const VarLockStatus prev_locked = tv_list_locked(l);
      const int called_emsg_start = called_emsg;

      tv_list_set_lock(l, VAR_FIXED);  // disallow the list changing here
      for (; li != NULL; li = TV_LIST_ITEM_NEXT(l, li)) {
        argv[0] = *rettv;
        argv[1] = *TV_LIST_ITEM_TV(li);
        rettv->v_type = VAR_UNKNOWN;
        const int r = call_func((char *)func_name, -1, rettv, 2, argv, &funcexe);
        tv_clear(&argv[0]);
        if (r == FAIL || called_emsg != called_emsg_start) {
          break;
        }
      }
      tv_list_set_lock(l, prev_locked);
    }
  } else {
    const blob_T *const b = argvars[0].vval.v_blob;
    int i;

    if (argvars[2].v_type == VAR_UNKNOWN) {
      if (tv_blob_len(b) == 0) {
        semsg(_(e_reduceempty), "Blob");
        return;
      }
      initial.v_type = VAR_NUMBER;
      initial.vval.v_number = tv_blob_get(b, 0);
      i = 1;
    } else if (argvars[2].v_type != VAR_NUMBER) {
      emsg(_(e_number_exp));
      return;
    } else {
      initial = argvars[2];
      i = 0;
    }

    tv_copy(&initial, rettv);
    for (; i < tv_blob_len(b); i++) {
      argv[0] = *rettv;
      argv[1].v_type = VAR_NUMBER;
      argv[1].vval.v_number = tv_blob_get(b, i);
      if (call_func((char *)func_name, -1, rettv, 2, argv, &funcexe) == FAIL) {
        return;
      }
    }
  }
}

#define SP_NOMOVE       0x01        ///< don't move cursor
#define SP_REPEAT       0x02        ///< repeat to find outer pair
#define SP_RETCOUNT     0x04        ///< return matchcount
#define SP_SETPCMARK    0x08        ///< set previous context mark
#define SP_START        0x10        ///< accept match at start position
#define SP_SUBPAT       0x20        ///< return nr of matching sub-pattern
#define SP_END          0x40        ///< leave cursor at end of match
#define SP_COLUMN       0x80        ///< start at cursor column

/// Get flags for a search function.
/// Possibly sets "p_ws".
///
/// @return  BACKWARD, FORWARD or zero (for an error).
static int get_search_arg(typval_T *varp, int *flagsp)
{
  int dir = FORWARD;

  if (varp->v_type != VAR_UNKNOWN) {
    char nbuf[NUMBUFLEN];
    const char *flags = tv_get_string_buf_chk(varp, nbuf);
    if (flags == NULL) {
      return 0;  // Type error; errmsg already given.
    }
    int mask;
    while (*flags != NUL) {
      switch (*flags) {
      case 'b':
        dir = BACKWARD; break;
      case 'w':
        p_ws = true; break;
      case 'W':
        p_ws = false; break;
      default:
        mask = 0;
        if (flagsp != NULL) {
          switch (*flags) {
          case 'c':
            mask = SP_START; break;
          case 'e':
            mask = SP_END; break;
          case 'm':
            mask = SP_RETCOUNT; break;
          case 'n':
            mask = SP_NOMOVE; break;
          case 'p':
            mask = SP_SUBPAT; break;
          case 'r':
            mask = SP_REPEAT; break;
          case 's':
            mask = SP_SETPCMARK; break;
          case 'z':
            mask = SP_COLUMN; break;
          }
        }
        if (mask == 0) {
          semsg(_(e_invarg2), flags);
          dir = 0;
        } else {
          *flagsp |= mask;
        }
      }
      if (dir == 0) {
        break;
      }
      flags++;
    }
  }
  return dir;
}

/// Shared by search() and searchpos() functions.
static int search_cmn(typval_T *argvars, pos_T *match_pos, int *flagsp)
{
  bool save_p_ws = p_ws;
  int retval = 0;               // default: FAIL
  long lnum_stop = 0;
  long time_limit = 0;
  int options = SEARCH_KEEP;
  bool use_skip = false;

  const char *const pat = tv_get_string(&argvars[0]);
  int dir = get_search_arg(&argvars[1], flagsp);  // May set p_ws.
  if (dir == 0) {
    goto theend;
  }
  int flags = *flagsp;
  if (flags & SP_START) {
    options |= SEARCH_START;
  }
  if (flags & SP_END) {
    options |= SEARCH_END;
  }
  if (flags & SP_COLUMN) {
    options |= SEARCH_COL;
  }

  // Optional arguments: line number to stop searching, timeout and skip.
  if (argvars[1].v_type != VAR_UNKNOWN && argvars[2].v_type != VAR_UNKNOWN) {
    lnum_stop = tv_get_number_chk(&argvars[2], NULL);
    if (lnum_stop < 0) {
      goto theend;
    }
    if (argvars[3].v_type != VAR_UNKNOWN) {
      time_limit = tv_get_number_chk(&argvars[3], NULL);
      if (time_limit < 0) {
        goto theend;
      }
      use_skip = eval_expr_valid_arg(&argvars[4]);
    }
  }

  // Set the time limit, if there is one.
  proftime_T tm = profile_setlimit(time_limit);

  // This function does not accept SP_REPEAT and SP_RETCOUNT flags.
  // Check to make sure only those flags are set.
  // Also, Only the SP_NOMOVE or the SP_SETPCMARK flag can be set. Both
  // flags cannot be set. Check for that condition also.
  if (((flags & (SP_REPEAT | SP_RETCOUNT)) != 0)
      || ((flags & SP_NOMOVE) && (flags & SP_SETPCMARK))) {
    semsg(_(e_invarg2), tv_get_string(&argvars[1]));
    goto theend;
  }

  pos_T save_cursor;
  pos_T pos = save_cursor = curwin->w_cursor;
  pos_T firstpos = { 0 };
  searchit_arg_T sia = {
    .sa_stop_lnum = (linenr_T)lnum_stop,
    .sa_tm = &tm,
  };

  int subpatnum;

  // Repeat until {skip} returns false.
  for (;;) {
    subpatnum
      = searchit(curwin, curbuf, &pos, NULL, dir, (char_u *)pat, 1, options, RE_SEARCH, &sia);
    // finding the first match again means there is no match where {skip}
    // evaluates to zero.
    if (firstpos.lnum != 0 && equalpos(pos, firstpos)) {
      subpatnum = FAIL;
    }

    if (subpatnum == FAIL || !use_skip) {
      // didn't find it or no skip argument
      break;
    }
    firstpos = pos;

    // If the skip expression matches, ignore this match.
    {
      const pos_T save_pos = curwin->w_cursor;

      curwin->w_cursor = pos;
      bool err = false;
      const bool do_skip = eval_expr_to_bool(&argvars[4], &err);
      curwin->w_cursor = save_pos;
      if (err) {
        // Evaluating {skip} caused an error, break here.
        subpatnum = FAIL;
        break;
      }
      if (!do_skip) {
        break;
      }
    }

    // clear the start flag to avoid getting stuck here
    options &= ~SEARCH_START;
  }

  if (subpatnum != FAIL) {
    if (flags & SP_SUBPAT) {
      retval = subpatnum;
    } else {
      retval = pos.lnum;
    }
    if (flags & SP_SETPCMARK) {
      setpcmark();
    }
    curwin->w_cursor = pos;
    if (match_pos != NULL) {
      // Store the match cursor position
      match_pos->lnum = pos.lnum;
      match_pos->col = pos.col + 1;
    }
    // "/$" will put the cursor after the end of the line, may need to
    // correct that here
    check_cursor();
  }

  // If 'n' flag is used: restore cursor position.
  if (flags & SP_NOMOVE) {
    curwin->w_cursor = save_cursor;
  } else {
    curwin->w_set_curswant = true;
  }
theend:
  p_ws = save_p_ws;

  return retval;
}

/// "rpcnotify()" function
static void f_rpcnotify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER || argvars[0].vval.v_number < 0) {
    semsg(_(e_invarg2), "Channel id must be a positive integer");
    return;
  }

  if (argvars[1].v_type != VAR_STRING) {
    semsg(_(e_invarg2), "Event type must be a string");
    return;
  }

  Array args = ARRAY_DICT_INIT;

  for (typval_T *tv = argvars + 2; tv->v_type != VAR_UNKNOWN; tv++) {
    ADD(args, vim_to_object(tv));
  }

  if (!rpc_send_event((uint64_t)argvars[0].vval.v_number,
                      tv_get_string(&argvars[1]), args)) {
    semsg(_(e_invarg2), "Channel doesn't exist");
    return;
  }

  rettv->vval.v_number = 1;
}

/// "rpcrequest()" function
static void f_rpcrequest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;
  const int l_provider_call_nesting = provider_call_nesting;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER || argvars[0].vval.v_number <= 0) {
    semsg(_(e_invarg2), "Channel id must be a positive integer");
    return;
  }

  if (argvars[1].v_type != VAR_STRING) {
    semsg(_(e_invarg2), "Method name must be a string");
    return;
  }

  Array args = ARRAY_DICT_INIT;

  for (typval_T *tv = argvars + 2; tv->v_type != VAR_UNKNOWN; tv++) {
    ADD(args, vim_to_object(tv));
  }

  sctx_T save_current_sctx;
  char *save_autocmd_fname, *save_autocmd_match;
  int save_autocmd_bufnr;
  funccal_entry_T funccal_entry;

  if (l_provider_call_nesting) {
    // If this is called from a provider function, restore the scope
    // information of the caller.
    save_current_sctx = current_sctx;
    save_autocmd_fname = autocmd_fname;
    save_autocmd_match = autocmd_match;
    save_autocmd_bufnr = autocmd_bufnr;
    save_funccal(&funccal_entry);

    current_sctx = provider_caller_scope.script_ctx;
    ga_grow(&exestack, 1);
    ((estack_T *)exestack.ga_data)[exestack.ga_len++] = provider_caller_scope.es_entry;
    autocmd_fname = provider_caller_scope.autocmd_fname;
    autocmd_match = provider_caller_scope.autocmd_match;
    autocmd_bufnr = provider_caller_scope.autocmd_bufnr;
    set_current_funccal((funccall_T *)(provider_caller_scope.funccalp));
  }

  Error err = ERROR_INIT;

  uint64_t chan_id = (uint64_t)argvars[0].vval.v_number;
  const char *method = tv_get_string(&argvars[1]);

  ArenaMem res_mem = NULL;
  Object result = rpc_send_call(chan_id, method, args, &res_mem, &err);

  if (l_provider_call_nesting) {
    current_sctx = save_current_sctx;
    exestack.ga_len--;
    autocmd_fname = save_autocmd_fname;
    autocmd_match = save_autocmd_match;
    autocmd_bufnr = save_autocmd_bufnr;
    restore_funccal();
  }

  if (ERROR_SET(&err)) {
    const char *name = NULL;
    Channel *chan = find_channel(chan_id);
    if (chan) {
      name = rpc_client_name(chan);
    }
    msg_ext_set_kind("rpc_error");
    if (name) {
      semsg_multiline("Error invoking '%s' on channel %" PRIu64 " (%s):\n%s",
                      method, chan_id, name, err.msg);
    } else {
      semsg_multiline("Error invoking '%s' on channel %" PRIu64 ":\n%s",
                      method, chan_id, err.msg);
    }

    goto end;
  }

  if (!object_to_vim(result, rettv, &err)) {
    semsg(_("Error converting the call result: %s"), err.msg);
  }

end:
  arena_mem_free(res_mem);
  api_clear_error(&err);
}

/// "rpcstart()" function (DEPRECATED)
static void f_rpcstart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_STRING
      || (argvars[1].v_type != VAR_LIST && argvars[1].v_type != VAR_UNKNOWN)) {
    // Wrong argument types
    emsg(_(e_invarg));
    return;
  }

  list_T *args = NULL;
  int argsl = 0;
  if (argvars[1].v_type == VAR_LIST) {
    args = argvars[1].vval.v_list;
    argsl = tv_list_len(args);
    // Assert that all list items are strings
    int i = 0;
    TV_LIST_ITER_CONST(args, arg, {
      if (TV_LIST_ITEM_TV(arg)->v_type != VAR_STRING) {
        semsg(_("E5010: List item %d of the second argument is not a string"),
              i);
        return;
      }
      i++;
    });
  }

  if (argvars[0].vval.v_string == NULL || argvars[0].vval.v_string[0] == NUL) {
    emsg(_(e_api_spawn_failed));
    return;
  }

  // Allocate extra memory for the argument vector and the NULL pointer
  int argvl = argsl + 2;
  char **argv = xmalloc(sizeof(char_u *) * (size_t)argvl);

  // Copy program name
  argv[0] = xstrdup(argvars[0].vval.v_string);

  int i = 1;
  // Copy arguments to the vector
  if (argsl > 0) {
    TV_LIST_ITER_CONST(args, arg, {
      argv[i++] = xstrdup(tv_get_string(TV_LIST_ITEM_TV(arg)));
    });
  }

  // The last item of argv must be NULL
  argv[i] = NULL;

  Channel *chan = channel_job_start(argv, CALLBACK_READER_INIT,
                                    CALLBACK_READER_INIT, CALLBACK_NONE,
                                    false, true, false, false,
                                    kChannelStdinPipe, NULL, 0, 0, NULL,
                                    &rettv->vval.v_number);
  if (chan) {
    channel_create_event(chan, NULL);
  }
}

/// "rpcstop()" function
static void f_rpcstop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_NUMBER) {
    // Wrong argument types
    emsg(_(e_invarg));
    return;
  }

  // if called with a job, stop it, else closes the channel
  uint64_t id = (uint64_t)argvars[0].vval.v_number;
  if (find_job(id, false)) {
    f_jobstop(argvars, rettv, fptr);
  } else {
    const char *error;
    rettv->vval.v_number =
      channel_close((uint64_t)argvars[0].vval.v_number, kChannelPartRpc, &error);
    if (!rettv->vval.v_number) {
      emsg(error);
    }
  }
}

/// "screenattr()" function
static void f_screenattr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int row = (int)tv_get_number_chk(&argvars[0], NULL) - 1;
  int col = (int)tv_get_number_chk(&argvars[1], NULL) - 1;

  ScreenGrid *grid;
  screenchar_adjust(&grid, &row, &col);

  int c;
  if (row < 0 || row >= grid->rows || col < 0 || col >= grid->cols) {
    c = -1;
  } else {
    c = grid->attrs[grid->line_offset[row] + (size_t)col];
  }
  rettv->vval.v_number = c;
}

/// "screenchar()" function
static void f_screenchar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int row = (int)tv_get_number_chk(&argvars[0], NULL) - 1;
  int col = (int)tv_get_number_chk(&argvars[1], NULL) - 1;

  ScreenGrid *grid;
  screenchar_adjust(&grid, &row, &col);

  int c;
  if (row < 0 || row >= grid->rows || col < 0 || col >= grid->cols) {
    c = -1;
  } else {
    c = utf_ptr2char((char *)grid->chars[grid->line_offset[row] + (size_t)col]);
  }
  rettv->vval.v_number = c;
}

/// "screenchars()" function
static void f_screenchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int row = (int)tv_get_number_chk(&argvars[0], NULL) - 1;
  int col = (int)tv_get_number_chk(&argvars[1], NULL) - 1;

  ScreenGrid *grid;
  screenchar_adjust(&grid, &row, &col);

  if (row < 0 || row >= grid->rows || col < 0 || col >= grid->cols) {
    tv_list_alloc_ret(rettv, 0);
    return;
  }
  int pcc[MAX_MCO];
  int c = utfc_ptr2char((char *)grid->chars[grid->line_offset[row] + (size_t)col], pcc);
  int composing_len = 0;
  while (pcc[composing_len] != 0) {
    composing_len++;
  }
  tv_list_alloc_ret(rettv, composing_len + 1);
  tv_list_append_number(rettv->vval.v_list, c);
  for (int i = 0; i < composing_len; i++) {
    tv_list_append_number(rettv->vval.v_list, pcc[i]);
  }
}

/// "screencol()" function
///
/// First column is 1 to be consistent with virtcol().
static void f_screencol(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = ui_current_col() + 1;
}

/// "screenrow()" function
static void f_screenrow(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = ui_current_row() + 1;
}

/// "screenstring()" function
static void f_screenstring(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_string = NULL;
  rettv->v_type = VAR_STRING;

  ScreenGrid *grid;
  int row = (int)tv_get_number_chk(&argvars[0], NULL) - 1;
  int col = (int)tv_get_number_chk(&argvars[1], NULL) - 1;

  screenchar_adjust(&grid, &row, &col);

  if (row < 0 || row >= grid->rows || col < 0 || col >= grid->cols) {
    return;
  }

  rettv->vval.v_string = xstrdup((char *)grid->chars[grid->line_offset[row] + (size_t)col]);
}

/// "search()" function
static void f_search(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int flags = 0;

  rettv->vval.v_number = search_cmn(argvars, NULL, &flags);
}

/// "searchdecl()" function
static void f_searchdecl(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int locally = 1;
  int thisblock = 0;
  bool error = false;

  rettv->vval.v_number = 1;     // default: FAIL

  const char *const name = tv_get_string_chk(&argvars[0]);
  if (argvars[1].v_type != VAR_UNKNOWN) {
    locally = tv_get_number_chk(&argvars[1], &error) == 0;
    if (!error && argvars[2].v_type != VAR_UNKNOWN) {
      thisblock = tv_get_number_chk(&argvars[2], &error) != 0;
    }
  }
  if (!error && name != NULL) {
    rettv->vval.v_number = find_decl((char_u *)name, strlen(name), locally,
                                     thisblock, SEARCH_KEEP) == FAIL;
  }
}

/// Used by searchpair() and searchpairpos()
static int searchpair_cmn(typval_T *argvars, pos_T *match_pos)
{
  bool save_p_ws = p_ws;
  int flags = 0;
  int retval = 0;  // default: FAIL
  long lnum_stop = 0;
  long time_limit = 0;

  // Get the three pattern arguments: start, middle, end. Will result in an
  // error if not a valid argument.
  char nbuf1[NUMBUFLEN];
  char nbuf2[NUMBUFLEN];
  const char *spat = tv_get_string_chk(&argvars[0]);
  const char *mpat = tv_get_string_buf_chk(&argvars[1], nbuf1);
  const char *epat = tv_get_string_buf_chk(&argvars[2], nbuf2);
  if (spat == NULL || mpat == NULL || epat == NULL) {
    goto theend;  // Type error.
  }

  // Handle the optional fourth argument: flags.
  int dir = get_search_arg(&argvars[3], &flags);   // may set p_ws.
  if (dir == 0) {
    goto theend;
  }

  // Don't accept SP_END or SP_SUBPAT.
  // Only one of the SP_NOMOVE or SP_SETPCMARK flags can be set.
  if ((flags & (SP_END | SP_SUBPAT)) != 0
      || ((flags & SP_NOMOVE) && (flags & SP_SETPCMARK))) {
    semsg(_(e_invarg2), tv_get_string(&argvars[3]));
    goto theend;
  }

  // Using 'r' implies 'W', otherwise it doesn't work.
  if (flags & SP_REPEAT) {
    p_ws = false;
  }

  // Optional fifth argument: skip expression.
  const typval_T *skip;
  if (argvars[3].v_type == VAR_UNKNOWN
      || argvars[4].v_type == VAR_UNKNOWN) {
    skip = NULL;
  } else {
    // Type is checked later.
    skip = &argvars[4];

    if (argvars[5].v_type != VAR_UNKNOWN) {
      lnum_stop = tv_get_number_chk(&argvars[5], NULL);
      if (lnum_stop < 0) {
        semsg(_(e_invarg2), tv_get_string(&argvars[5]));
        goto theend;
      }
      if (argvars[6].v_type != VAR_UNKNOWN) {
        time_limit = tv_get_number_chk(&argvars[6], NULL);
        if (time_limit < 0) {
          semsg(_(e_invarg2), tv_get_string(&argvars[6]));
          goto theend;
        }
      }
    }
  }

  retval = (int)do_searchpair(spat, mpat, epat, dir, skip,
                              flags, match_pos, (linenr_T)lnum_stop, time_limit);

theend:
  p_ws = save_p_ws;

  return retval;
}

/// "searchpair()" function
static void f_searchpair(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = searchpair_cmn(argvars, NULL);
}

/// "searchpairpos()" function
static void f_searchpairpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  pos_T match_pos;
  int lnum = 0;
  int col = 0;

  tv_list_alloc_ret(rettv, 2);

  if (searchpair_cmn(argvars, &match_pos) > 0) {
    lnum = match_pos.lnum;
    col = match_pos.col;
  }

  tv_list_append_number(rettv->vval.v_list, (varnumber_T)lnum);
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)col);
}

/// Search for a start/middle/end thing.
/// Used by searchpair(), see its documentation for the details.
///
/// @param spat  start pattern
/// @param mpat  middle pattern
/// @param epat  end pattern
/// @param dir  BACKWARD or FORWARD
/// @param skip  skip expression
/// @param flags  SP_SETPCMARK and other SP_ values
/// @param lnum_stop  stop at this line if not zero
/// @param time_limit  stop after this many msec
///
/// @returns  0 or -1 for no match,
long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir,
                   const typval_T *skip, int flags, pos_T *match_pos, linenr_T lnum_stop,
                   long time_limit)
  FUNC_ATTR_NONNULL_ARG(1, 2, 3)
{
  long retval = 0;
  int nest = 1;
  bool use_skip = false;
  int options = SEARCH_KEEP;

  // Make 'cpoptions' empty, the 'l' flag should not be used here.
  char *save_cpo = p_cpo;
  p_cpo = empty_option;

  // Set the time limit, if there is one.
  proftime_T tm = profile_setlimit(time_limit);

  // Make two search patterns: start/end (pat2, for in nested pairs) and
  // start/middle/end (pat3, for the top pair).
  const size_t pat2_len = strlen(spat) + strlen(epat) + 17;
  char_u *pat2 = xmalloc(pat2_len);
  const size_t pat3_len = strlen(spat) + strlen(mpat) + strlen(epat) + 25;
  char_u *pat3 = xmalloc(pat3_len);
  snprintf((char *)pat2, pat2_len, "\\m\\(%s\\m\\)\\|\\(%s\\m\\)", spat, epat);
  if (*mpat == NUL) {
    STRCPY(pat3, pat2);
  } else {
    snprintf((char *)pat3, pat3_len,
             "\\m\\(%s\\m\\)\\|\\(%s\\m\\)\\|\\(%s\\m\\)", spat, epat, mpat);
  }
  if (flags & SP_START) {
    options |= SEARCH_START;
  }

  if (skip != NULL) {
    use_skip = eval_expr_valid_arg(skip);
  }

  pos_T save_cursor = curwin->w_cursor;
  pos_T pos = curwin->w_cursor;
  pos_T firstpos;
  clearpos(&firstpos);
  pos_T foundpos;
  clearpos(&foundpos);
  char_u *pat = pat3;
  for (;;) {
    searchit_arg_T sia = {
      .sa_stop_lnum = lnum_stop,
      .sa_tm = &tm,
    };

    int n = searchit(curwin, curbuf, &pos, NULL, dir, pat, 1L,
                     options, RE_SEARCH, &sia);
    if (n == FAIL || (firstpos.lnum != 0 && equalpos(pos, firstpos))) {
      // didn't find it or found the first match again: FAIL
      break;
    }

    if (firstpos.lnum == 0) {
      firstpos = pos;
    }
    if (equalpos(pos, foundpos)) {
      // Found the same position again.  Can happen with a pattern that
      // has "\zs" at the end and searching backwards.  Advance one
      // character and try again.
      if (dir == BACKWARD) {
        decl(&pos);
      } else {
        incl(&pos);
      }
    }
    foundpos = pos;

    // clear the start flag to avoid getting stuck here
    options &= ~SEARCH_START;

    // If the skip pattern matches, ignore this match.
    if (use_skip) {
      pos_T save_pos = curwin->w_cursor;
      curwin->w_cursor = pos;
      bool err = false;
      const bool r = eval_expr_to_bool(skip, &err);
      curwin->w_cursor = save_pos;
      if (err) {
        // Evaluating {skip} caused an error, break here.
        curwin->w_cursor = save_cursor;
        retval = -1;
        break;
      }
      if (r) {
        continue;
      }
    }

    if ((dir == BACKWARD && n == 3) || (dir == FORWARD && n == 2)) {
      // Found end when searching backwards or start when searching
      // forward: nested pair.
      nest++;
      pat = pat2;               // nested, don't search for middle
    } else {
      // Found end when searching forward or start when searching
      // backward: end of (nested) pair; or found middle in outer pair.
      if (--nest == 1) {
        pat = pat3;             // outer level, search for middle
      }
    }

    if (nest == 0) {
      // Found the match: return matchcount or line number.
      if (flags & SP_RETCOUNT) {
        retval++;
      } else {
        retval = pos.lnum;
      }
      if (flags & SP_SETPCMARK) {
        setpcmark();
      }
      curwin->w_cursor = pos;
      if (!(flags & SP_REPEAT)) {
        break;
      }
      nest = 1;             // search for next unmatched
    }
  }

  if (match_pos != NULL) {
    // Store the match cursor position
    match_pos->lnum = curwin->w_cursor.lnum;
    match_pos->col = curwin->w_cursor.col + 1;
  }

  // If 'n' flag is used or search failed: restore cursor position.
  if ((flags & SP_NOMOVE) || retval == 0) {
    curwin->w_cursor = save_cursor;
  }

  xfree(pat2);
  xfree(pat3);
  if (p_cpo == empty_option) {
    p_cpo = save_cpo;
  } else {
    // Darn, evaluating the {skip} expression changed the value.
    // If it's still empty it was changed and restored, need to restore in
    // the complicated way.
    if (*p_cpo == NUL) {
      set_option_value_give_err("cpo", 0L, save_cpo, 0);
    }
    free_string_option(save_cpo);
  }

  return retval;
}

/// "searchpos()" function
static void f_searchpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  pos_T match_pos;
  int flags = 0;

  const int n = search_cmn(argvars, &match_pos, &flags);

  tv_list_alloc_ret(rettv, 2 + (!!(flags & SP_SUBPAT)));

  const int lnum = (n > 0 ? match_pos.lnum : 0);
  const int col = (n > 0 ? match_pos.col : 0);

  tv_list_append_number(rettv->vval.v_list, (varnumber_T)lnum);
  tv_list_append_number(rettv->vval.v_list, (varnumber_T)col);
  if (flags & SP_SUBPAT) {
    tv_list_append_number(rettv->vval.v_list, (varnumber_T)n);
  }
}

/// "serverlist()" function
static void f_serverlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  size_t n;
  char **addrs = server_address_list(&n);

  // Copy addrs into a linked list.
  list_T *const l = tv_list_alloc_ret(rettv, (ptrdiff_t)n);
  for (size_t i = 0; i < n; i++) {
    tv_list_append_allocated_string(l, addrs[i]);
  }
  xfree(addrs);
}

/// "serverstart()" function
static void f_serverstart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;  // Address of the new server

  if (check_secure()) {
    return;
  }

  char *address;
  // If the user supplied an address, use it, otherwise use a temp.
  if (argvars[0].v_type != VAR_UNKNOWN) {
    if (argvars[0].v_type != VAR_STRING) {
      emsg(_(e_invarg));
      return;
    }
    address = xstrdup(tv_get_string(argvars));
  } else {
    address = server_address_new(NULL);
  }

  int result = server_start(address);
  xfree(address);

  if (result != 0) {
    semsg("Failed to start server: %s",
          result > 0 ? "Unknown system error" : uv_strerror(result));
    return;
  }

  // Since it's possible server_start adjusted the given {address} (e.g.,
  // "localhost:" will now have a port), return the final value to the user.
  size_t n;
  char **addrs = server_address_list(&n);
  rettv->vval.v_string = addrs[n - 1];

  n--;
  for (size_t i = 0; i < n; i++) {
    xfree(addrs[i]);
  }
  xfree(addrs);
}

/// "serverstop()" function
static void f_serverstop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type != VAR_STRING) {
    emsg(_(e_invarg));
    return;
  }

  rettv->v_type = VAR_NUMBER;
  rettv->vval.v_number = 0;
  if (argvars[0].vval.v_string) {
    bool rv = server_stop(argvars[0].vval.v_string);
    rettv->vval.v_number = (rv ? 1 : 0);
  }
}

/// Set the cursor or mark position.
/// If 'charpos' is true, then use the column number as a character offset.
/// Otherwise use the column number as a byte offset.
static void set_position(typval_T *argvars, typval_T *rettv, bool charpos)
{
  colnr_T curswant = -1;

  rettv->vval.v_number = -1;
  const char *const name = tv_get_string_chk(argvars);
  if (name == NULL) {
    return;
  }

  pos_T pos;
  int fnum;
  if (list2fpos(&argvars[1], &pos, &fnum, &curswant, charpos) != OK) {
    return;
  }

  if (pos.col != MAXCOL && --pos.col < 0) {
    pos.col = 0;
  }
  if (name[0] == '.' && name[1] == NUL) {
    // set cursor; "fnum" is ignored
    curwin->w_cursor = pos;
    if (curswant >= 0) {
      curwin->w_curswant = curswant - 1;
      curwin->w_set_curswant = false;
    }
    check_cursor();
    rettv->vval.v_number = 0;
  } else if (name[0] == '\'' && name[1] != NUL && name[2] == NUL) {
    // set mark
    if (setmark_pos((uint8_t)name[1], &pos, fnum, NULL) == OK) {
      rettv->vval.v_number = 0;
    }
  } else {
    emsg(_(e_invarg));
  }
}

/// "setcharpos()" function
static void f_setcharpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  set_position(argvars, rettv, true);
}

static void f_setcharsearch(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_DICT) {
    emsg(_(e_dictreq));
    return;
  }

  dict_T *d = argvars[0].vval.v_dict;
  if (d == NULL) {
    return;
  }

  char_u *const csearch = (char_u *)tv_dict_get_string(d, "char", false);
  if (csearch != NULL) {
    int pcc[MAX_MCO];
    const int c = utfc_ptr2char((char *)csearch, pcc);
    set_last_csearch(c, csearch, utfc_ptr2len((char *)csearch));
  }

  dictitem_T *di = tv_dict_find(d, S_LEN("forward"));
  if (di != NULL) {
    set_csearch_direction(tv_get_number(&di->di_tv) ? FORWARD : BACKWARD);
  }

  di = tv_dict_find(d, S_LEN("until"));
  if (di != NULL) {
    set_csearch_until(!!tv_get_number(&di->di_tv));
  }
}

/// "setcursorcharpos" function
static void f_setcursorcharpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  set_cursorpos(argvars, rettv, true);
}

/// "setenv()" function
static void f_setenv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char namebuf[NUMBUFLEN];
  char valbuf[NUMBUFLEN];
  const char *name = tv_get_string_buf(&argvars[0], namebuf);

  if (argvars[1].v_type == VAR_SPECIAL
      && argvars[1].vval.v_special == kSpecialVarNull) {
    vim_unsetenv_ext(name);
  } else {
    vim_setenv_ext(name, tv_get_string_buf(&argvars[1], valbuf));
  }
}

/// "setfperm({fname}, {mode})" function
static void f_setfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = 0;

  const char *const fname = tv_get_string_chk(&argvars[0]);
  if (fname == NULL) {
    return;
  }

  char modebuf[NUMBUFLEN];
  const char *const mode_str = tv_get_string_buf_chk(&argvars[1], modebuf);
  if (mode_str == NULL) {
    return;
  }
  if (strlen(mode_str) != 9) {
    semsg(_(e_invarg2), mode_str);
    return;
  }

  int mask = 1;
  int mode = 0;
  for (int i = 8; i >= 0; i--) {
    if (mode_str[i] != '-') {
      mode |= mask;
    }
    mask = mask << 1;
  }
  rettv->vval.v_number = os_setperm(fname, mode) == OK;
}

/// "setpos()" function
static void f_setpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  set_position(argvars, rettv, false);
}

/// Translate a register type string to the yank type and block length
static int get_yank_type(char **const pp, MotionType *const yank_type, long *const block_len)
  FUNC_ATTR_NONNULL_ALL
{
  char *stropt = *pp;
  switch (*stropt) {
  case 'v':
  case 'c':  // character-wise selection
    *yank_type = kMTCharWise;
    break;
  case 'V':
  case 'l':  // line-wise selection
    *yank_type = kMTLineWise;
    break;
  case 'b':
  case Ctrl_V:  // block-wise selection
    *yank_type = kMTBlockWise;
    if (ascii_isdigit(stropt[1])) {
      stropt++;
      *block_len = getdigits_long(&stropt, false, 0) - 1;
      stropt--;
    }
    break;
  default:
    return FAIL;
  }
  *pp = stropt;
  return OK;
}

/// "setreg()" function
static void f_setreg(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  bool append = false;

  long block_len = -1;
  MotionType yank_type = kMTUnknown;

  rettv->vval.v_number = 1;  // FAIL is default.

  const char *const strregname = tv_get_string_chk(argvars);
  if (strregname == NULL) {
    return;  // Type error; errmsg already given.
  }
  char regname = *strregname;
  if (regname == 0 || regname == '@') {
    regname = '"';
  }

  const typval_T *regcontents = NULL;
  char pointreg = 0;
  if (argvars[1].v_type == VAR_DICT) {
    dict_T *const d = argvars[1].vval.v_dict;

    if (tv_dict_len(d) == 0) {
      // Empty dict, clear the register (like setreg(0, []))
      char *lstval[2] = { NULL, NULL };
      write_reg_contents_lst(regname, lstval, false, kMTUnknown, -1);
      return;
    }

    dictitem_T *const di = tv_dict_find(d, "regcontents", -1);
    if (di != NULL) {
      regcontents = &di->di_tv;
    }

    const char *stropt = tv_dict_get_string(d, "regtype", false);
    if (stropt != NULL) {
      const int ret = get_yank_type((char **)&stropt, &yank_type, &block_len);

      if (ret == FAIL || *(++stropt) != NUL) {
        semsg(_(e_invargval), "value");
        return;
      }
    }

    if (regname == '"') {
      stropt = tv_dict_get_string(d, "points_to", false);
      if (stropt != NULL) {
        pointreg = *stropt;
        regname = pointreg;
      }
    } else if (tv_dict_get_number(d, "isunnamed")) {
      pointreg = regname;
    }
  } else {
    regcontents = &argvars[1];
  }

  bool set_unnamed = false;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    if (yank_type != kMTUnknown) {
      semsg(_(e_toomanyarg), "setreg");
      return;
    }

    const char *stropt = tv_get_string_chk(&argvars[2]);
    if (stropt == NULL) {
      return;  // Type error.
    }
    for (; *stropt != NUL; stropt++) {
      switch (*stropt) {
      case 'a':
      case 'A':    // append
        append = true;
        break;
      case 'u':
      case '"':    // unnamed register
        set_unnamed = true;
        break;
      default:
        get_yank_type((char **)&stropt, &yank_type, &block_len);
      }
    }
  }

  if (regcontents != NULL && regcontents->v_type == VAR_LIST) {
    list_T *const ll = regcontents->vval.v_list;
    // If the list is NULL handle like an empty list.
    const int len = tv_list_len(ll);

    // First half: use for pointers to result lines; second half: use for
    // pointers to allocated copies.
    char **lstval = xmalloc(sizeof(char *) * (((size_t)len + 1) * 2));
    const char **curval = (const char **)lstval;
    char **allocval = lstval + len + 2;
    char **curallocval = allocval;

    TV_LIST_ITER_CONST(ll, li, {
      char buf[NUMBUFLEN];
      *curval = tv_get_string_buf_chk(TV_LIST_ITEM_TV(li), buf);
      if (*curval == NULL) {
        goto free_lstval;
      }
      if (*curval == buf) {
        // Need to make a copy,
        // next tv_get_string_buf_chk() will overwrite the string.
        *curallocval = xstrdup(*curval);
        *curval = *curallocval;
        curallocval++;
      }
      curval++;
    });
    *curval++ = NULL;

    write_reg_contents_lst(regname, lstval, append, yank_type, (colnr_T)block_len);

free_lstval:
    while (curallocval > allocval) {
      xfree(*--curallocval);
    }
    xfree(lstval);
  } else if (regcontents != NULL) {
    const char *const strval = tv_get_string_chk(regcontents);
    if (strval == NULL) {
      return;
    }
    write_reg_contents_ex(regname, strval, (ssize_t)strlen(strval),
                          append, yank_type, (colnr_T)block_len);
  }
  if (pointreg != 0) {
    get_yank_register(pointreg, YREG_YANK);
  }
  rettv->vval.v_number = 0;

  if (set_unnamed) {
    // Discard the result. We already handle the error case.
    op_reg_set_previous(regname);
  }
}

/// "settagstack()" function
static void f_settagstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  static char *e_invact2 = N_("E962: Invalid action: '%s'");
  char action = 'r';

  rettv->vval.v_number = -1;

  // first argument: window number or id
  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
  if (wp == NULL) {
    return;
  }

  // second argument: dict with items to set in the tag stack
  if (argvars[1].v_type != VAR_DICT) {
    emsg(_(e_dictreq));
    return;
  }
  dict_T *d = argvars[1].vval.v_dict;
  if (d == NULL) {
    return;
  }

  // third argument: action - 'a' for append and 'r' for replace.
  // default is to replace the stack.
  if (argvars[2].v_type == VAR_UNKNOWN) {
    action = 'r';
  } else if (argvars[2].v_type == VAR_STRING) {
    const char *actstr;
    actstr = tv_get_string_chk(&argvars[2]);
    if (actstr == NULL) {
      return;
    }
    if ((*actstr == 'r' || *actstr == 'a' || *actstr == 't')
        && actstr[1] == NUL) {
      action = *actstr;
    } else {
      semsg(_(e_invact2), actstr);
      return;
    }
  } else {
    emsg(_(e_stringreq));
    return;
  }

  if (set_tagstack(wp, d, action) == OK) {
    rettv->vval.v_number = 0;
  }
}

/// f_sha256 - sha256({string}) function
static void f_sha256(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *p = tv_get_string(&argvars[0]);
  const char *hash = sha256_bytes((const uint8_t *)p, strlen(p), NULL, 0);

  // make a copy of the hash (sha256_bytes returns a static buffer)
  rettv->vval.v_string = xstrdup(hash);
  rettv->v_type = VAR_STRING;
}

/// "shellescape({string})" function
static void f_shellescape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const bool do_special = non_zero_arg(&argvars[1]);

  rettv->vval.v_string =
    vim_strsave_shellescape(tv_get_string(&argvars[0]), do_special, do_special);
  rettv->v_type = VAR_STRING;
}

/// shiftwidth() function
static void f_shiftwidth(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = 0;

  if (argvars[0].v_type != VAR_UNKNOWN) {
    long col = (long)tv_get_number_chk(argvars, NULL);
    if (col < 0) {
      return;  // type error; errmsg already given
    }
    rettv->vval.v_number = get_sw_value_col(curbuf, (colnr_T)col);
    return;
  }
  rettv->vval.v_number = get_sw_value(curbuf);
}

/// "simplify()" function
static void f_simplify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const p = tv_get_string(&argvars[0]);
  rettv->vval.v_string = xstrdup(p);
  simplify_filename((char_u *)rettv->vval.v_string);  // Simplify in place.
  rettv->v_type = VAR_STRING;
}

/// "sockconnect()" function
static void f_sockconnect(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_STRING || argvars[1].v_type != VAR_STRING) {
    emsg(_(e_invarg));
    return;
  }
  if (argvars[2].v_type != VAR_DICT && argvars[2].v_type != VAR_UNKNOWN) {
    // Wrong argument types
    semsg(_(e_invarg2), "expected dictionary");
    return;
  }

  const char *mode = tv_get_string(&argvars[0]);
  const char *address = tv_get_string(&argvars[1]);

  bool tcp;
  if (strcmp(mode, "tcp") == 0) {
    tcp = true;
  } else if (strcmp(mode, "pipe") == 0) {
    tcp = false;
  } else {
    semsg(_(e_invarg2), "invalid mode");
    return;
  }

  bool rpc = false;
  CallbackReader on_data = CALLBACK_READER_INIT;
  if (argvars[2].v_type == VAR_DICT) {
    dict_T *opts = argvars[2].vval.v_dict;
    rpc = tv_dict_get_number(opts, "rpc") != 0;

    if (!tv_dict_get_callback(opts, S_LEN("on_data"), &on_data.cb)) {
      return;
    }
    on_data.buffered = tv_dict_get_number(opts, "data_buffered");
    if (on_data.buffered && on_data.cb.type == kCallbackNone) {
      on_data.self = opts;
    }
  }

  const char *error = NULL;
  uint64_t id = channel_connect(tcp, address, rpc, on_data, 50, &error);

  if (error) {
    semsg(_("connection failed: %s"), error);
  }

  rettv->vval.v_number = (varnumber_T)id;
  rettv->v_type = VAR_NUMBER;
}

/// "stdioopen()" function
static void f_stdioopen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_DICT) {
    emsg(_(e_invarg));
    return;
  }

  CallbackReader on_stdin = CALLBACK_READER_INIT;
  dict_T *opts = argvars[0].vval.v_dict;
  bool rpc = tv_dict_get_number(opts, "rpc") != 0;

  if (!tv_dict_get_callback(opts, S_LEN("on_stdin"), &on_stdin.cb)) {
    return;
  }
  if (!tv_dict_get_callback(opts, S_LEN("on_print"), &on_print)) {
    return;
  }

  on_stdin.buffered = tv_dict_get_number(opts, "stdin_buffered");
  if (on_stdin.buffered && on_stdin.cb.type == kCallbackNone) {
    on_stdin.self = opts;
  }

  const char *error;
  uint64_t id = channel_from_stdio(rpc, on_stdin, &error);
  if (!id) {
    semsg(e_stdiochan2, error);
  }

  rettv->vval.v_number = (varnumber_T)id;
  rettv->v_type = VAR_NUMBER;
}

/// "reltimefloat()" function
static void f_reltimefloat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
  FUNC_ATTR_NONNULL_ALL
{
  proftime_T tm;

  rettv->v_type = VAR_FLOAT;
  rettv->vval.v_float = 0;
  if (list2proftime(&argvars[0], &tm) == OK) {
    rettv->vval.v_float = (float_T)profile_signed(tm) / 1000000000.0;
  }
}

/// "soundfold({word})" function
static void f_soundfold(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  const char *const s = tv_get_string(&argvars[0]);
  rettv->vval.v_string = eval_soundfold(s);
}

/// "spellbadword()" function
static void f_spellbadword(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const int wo_spell_save = curwin->w_p_spell;

  if (!curwin->w_p_spell) {
    did_set_spelllang(curwin);
    curwin->w_p_spell = true;
  }

  if (*curwin->w_s->b_p_spl == NUL) {
    emsg(_(e_no_spell));
    curwin->w_p_spell = wo_spell_save;
    return;
  }

  const char *word = "";
  hlf_T attr = HLF_COUNT;
  size_t len = 0;
  if (argvars[0].v_type == VAR_UNKNOWN) {
    // Find the start and length of the badly spelled word.
    len = spell_move_to(curwin, FORWARD, true, true, &attr);
    if (len != 0) {
      word = get_cursor_pos_ptr();
      curwin->w_set_curswant = true;
    }
  } else if (*curbuf->b_s.b_p_spl != NUL) {
    const char *str = tv_get_string_chk(&argvars[0]);
    int capcol = -1;

    if (str != NULL) {
      // Check the argument for spelling.
      while (*str != NUL) {
        len = spell_check(curwin, (char_u *)str, &attr, &capcol, false);
        if (attr != HLF_COUNT) {
          word = str;
          break;
        }
        str += len;
        capcol -= (int)len;
        len = 0;
      }
    }
  }
  curwin->w_p_spell = wo_spell_save;

  assert(len <= INT_MAX);
  tv_list_alloc_ret(rettv, 2);
  tv_list_append_string(rettv->vval.v_list, word, (ssize_t)len);
  tv_list_append_string(rettv->vval.v_list,
                        (attr == HLF_SPB ? "bad" :
                         attr == HLF_SPR ? "rare" :
                         attr == HLF_SPL ? "local" :
                         attr == HLF_SPC ? "caps" : NULL), -1);
}

/// "spellsuggest()" function
static void f_spellsuggest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  garray_T ga = GA_EMPTY_INIT_VALUE;
  const int wo_spell_save = curwin->w_p_spell;

  if (!curwin->w_p_spell) {
    did_set_spelllang(curwin);
    curwin->w_p_spell = true;
  }

  if (*curwin->w_s->b_p_spl == NUL) {
    emsg(_(e_no_spell));
    curwin->w_p_spell = wo_spell_save;
    return;
  }

  int maxcount;
  bool need_capital = false;
  const char *const str = tv_get_string(&argvars[0]);
  if (argvars[1].v_type != VAR_UNKNOWN) {
    bool typeerr = false;
    maxcount = (int)tv_get_number_chk(&argvars[1], &typeerr);
    if (maxcount <= 0) {
      goto f_spellsuggest_return;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      need_capital = tv_get_number_chk(&argvars[2], &typeerr);
      if (typeerr) {
        goto f_spellsuggest_return;
      }
    }
  } else {
    maxcount = 25;
  }

  spell_suggest_list(&ga, (char_u *)str, maxcount, need_capital, false);

f_spellsuggest_return:
  tv_list_alloc_ret(rettv, (ptrdiff_t)ga.ga_len);
  for (int i = 0; i < ga.ga_len; i++) {
    char *const p = ((char **)ga.ga_data)[i];
    tv_list_append_allocated_string(rettv->vval.v_list, p);
  }
  ga_clear(&ga);
  curwin->w_p_spell = wo_spell_save;
}

static void f_split(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  colnr_T col = 0;
  bool keepempty = false;
  bool typeerr = false;

  // Make 'cpoptions' empty, the 'l' flag should not be used here.
  char *save_cpo = p_cpo;
  p_cpo = empty_option;

  const char *str = tv_get_string(&argvars[0]);
  const char *pat = NULL;
  char patbuf[NUMBUFLEN];
  if (argvars[1].v_type != VAR_UNKNOWN) {
    pat = tv_get_string_buf_chk(&argvars[1], patbuf);
    if (pat == NULL) {
      typeerr = true;
    }
    if (argvars[2].v_type != VAR_UNKNOWN) {
      keepempty = (bool)tv_get_bool_chk(&argvars[2], &typeerr);
    }
  }
  if (pat == NULL || *pat == NUL) {
    pat = "[\\x01- ]\\+";
  }

  tv_list_alloc_ret(rettv, kListLenMayKnow);

  if (typeerr) {
    goto theend;
  }

  regmatch_T regmatch = {
    .regprog = vim_regcomp((char *)pat, RE_MAGIC + RE_STRING),
    .startp = { NULL },
    .endp = { NULL },
    .rm_ic = false,
  };
  if (regmatch.regprog != NULL) {
    while (*str != NUL || keepempty) {
      bool match;
      if (*str == NUL) {
        match = false;  // Empty item at the end.
      } else {
        match = vim_regexec_nl(&regmatch, (char_u *)str, col);
      }
      const char *end;
      if (match) {
        end = (const char *)regmatch.startp[0];
      } else {
        end = str + strlen(str);
      }
      if (keepempty || end > str || (tv_list_len(rettv->vval.v_list) > 0
                                     && *str != NUL
                                     && match
                                     && end < (const char *)regmatch.endp[0])) {
        tv_list_append_string(rettv->vval.v_list, str, end - str);
      }
      if (!match) {
        break;
      }
      // Advance to just after the match.
      if (regmatch.endp[0] > str) {
        col = 0;
      } else {
        // Don't get stuck at the same match.
        col = utfc_ptr2len(regmatch.endp[0]);
      }
      str = (const char *)regmatch.endp[0];
    }

    vim_regfree(regmatch.regprog);
  }

theend:
  p_cpo = save_cpo;
}

/// "stdpath(type)" function
static void f_stdpath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;

  const char *const p = tv_get_string_chk(&argvars[0]);
  if (p == NULL) {
    return;  // Type error; errmsg already given.
  }

  if (strequal(p, "config")) {
    rettv->vval.v_string = get_xdg_home(kXDGConfigHome);
  } else if (strequal(p, "data")) {
    rettv->vval.v_string = get_xdg_home(kXDGDataHome);
  } else if (strequal(p, "cache")) {
    rettv->vval.v_string = get_xdg_home(kXDGCacheHome);
  } else if (strequal(p, "state")) {
    rettv->vval.v_string = get_xdg_home(kXDGStateHome);
  } else if (strequal(p, "log")) {
    rettv->vval.v_string = get_xdg_home(kXDGStateHome);
  } else if (strequal(p, "run")) {
    rettv->vval.v_string = stdpaths_get_xdg_var(kXDGRuntimeDir);
  } else if (strequal(p, "config_dirs")) {
    get_xdg_var_list(kXDGConfigDirs, rettv);
  } else if (strequal(p, "data_dirs")) {
    get_xdg_var_list(kXDGDataDirs, rettv);
  } else {
    semsg(_("E6100: \"%s\" is not a valid stdpath"), p);
  }
}

/// "str2float()" function
static void f_str2float(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char *p = skipwhite(tv_get_string(&argvars[0]));
  bool isneg = (*p == '-');

  if (*p == '+' || *p == '-') {
    p = skipwhite(p + 1);
  }
  (void)string2float(p, &rettv->vval.v_float);
  if (isneg) {
    rettv->vval.v_float *= -1;
  }
  rettv->v_type = VAR_FLOAT;
}

/// "str2list()" function
static void f_str2list(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenUnknown);
  const char_u *p = (const char_u *)tv_get_string(&argvars[0]);

  for (; *p != NUL; p += utf_ptr2len((char *)p)) {
    tv_list_append_number(rettv->vval.v_list, utf_ptr2char((char *)p));
  }
}

/// "str2nr()" function
static void f_str2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int base = 10;
  int what = 0;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    base = (int)tv_get_number(&argvars[1]);
    if (base != 2 && base != 8 && base != 10 && base != 16) {
      emsg(_(e_invarg));
      return;
    }
    if (argvars[2].v_type != VAR_UNKNOWN && tv_get_bool(&argvars[2])) {
      what |= STR2NR_QUOTE;
    }
  }

  char_u *p = (char_u *)skipwhite(tv_get_string(&argvars[0]));
  bool isneg = (*p == '-');
  if (*p == '+' || *p == '-') {
    p = (char_u *)skipwhite((char *)p + 1);
  }
  switch (base) {
  case 2:
    what |= STR2NR_BIN | STR2NR_FORCE;
    break;
  case 8:
    what |= STR2NR_OCT | STR2NR_OOCT | STR2NR_FORCE;
    break;
  case 16:
    what |= STR2NR_HEX | STR2NR_FORCE;
    break;
  }
  varnumber_T n;
  vim_str2nr((char *)p, NULL, NULL, what, &n, NULL, 0, false);
  // Text after the number is silently ignored.
  if (isneg) {
    rettv->vval.v_number = -n;
  } else {
    rettv->vval.v_number = n;
  }
}

/// "strftime({format}[, {time}])" function
static void f_strftime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  time_t seconds;

  rettv->v_type = VAR_STRING;

  char *p = (char *)tv_get_string(&argvars[0]);
  if (argvars[1].v_type == VAR_UNKNOWN) {
    seconds = time(NULL);
  } else {
    seconds = (time_t)tv_get_number(&argvars[1]);
  }

  struct tm curtime;
  struct tm *curtime_ptr = os_localtime_r(&seconds, &curtime);
  // MSVC returns NULL for an invalid value of seconds.
  if (curtime_ptr == NULL) {
    rettv->vval.v_string = xstrdup(_("(Invalid)"));
  } else {
    vimconv_T conv;

    conv.vc_type = CONV_NONE;
    char *enc = (char *)enc_locale();
    convert_setup(&conv, p_enc, enc);
    if (conv.vc_type != CONV_NONE) {
      p = string_convert(&conv, p, NULL);
    }
    char result_buf[256];
    if (p == NULL || strftime(result_buf, sizeof(result_buf), p, curtime_ptr) == 0) {
      result_buf[0] = NUL;
    }

    if (conv.vc_type != CONV_NONE) {
      xfree(p);
    }
    convert_setup(&conv, enc, p_enc);
    if (conv.vc_type != CONV_NONE) {
      rettv->vval.v_string = string_convert(&conv, result_buf, NULL);
    } else {
      rettv->vval.v_string = xstrdup(result_buf);
    }

    // Release conversion descriptors.
    convert_setup(&conv, NULL, NULL);
    xfree(enc);
  }
}

/// "strgetchar()" function
static void f_strgetchar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = -1;

  const char *const str = tv_get_string_chk(&argvars[0]);
  if (str == NULL) {
    return;
  }
  bool error = false;
  varnumber_T charidx = tv_get_number_chk(&argvars[1], &error);
  if (error) {
    return;
  }

  const size_t len = strlen(str);
  size_t byteidx = 0;

  while (charidx >= 0 && byteidx < len) {
    if (charidx == 0) {
      rettv->vval.v_number = utf_ptr2char(str + byteidx);
      break;
    }
    charidx--;
    byteidx += (size_t)utf_ptr2len(str + byteidx);
  }
}

/// "stridx()" function
static void f_stridx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = -1;

  char buf[NUMBUFLEN];
  const char *const needle = tv_get_string_chk(&argvars[1]);
  const char *haystack = tv_get_string_buf_chk(&argvars[0], buf);
  const char *const haystack_start = haystack;
  if (needle == NULL || haystack == NULL) {
    return;  // Type error; errmsg already given.
  }

  if (argvars[2].v_type != VAR_UNKNOWN) {
    bool error = false;

    const ptrdiff_t start_idx = (ptrdiff_t)tv_get_number_chk(&argvars[2],
                                                             &error);
    if (error || start_idx >= (ptrdiff_t)strlen(haystack)) {
      return;
    }
    if (start_idx >= 0) {
      haystack += start_idx;
    }
  }

  const char *pos = strstr(haystack, needle);
  if (pos != NULL) {
    rettv->vval.v_number = (varnumber_T)(pos - haystack_start);
  }
}

/// "string()" function
static void f_string(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = encode_tv2string(&argvars[0], NULL);
}

/// "strlen()" function
static void f_strlen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = (varnumber_T)strlen(tv_get_string(&argvars[0]));
}

static void strchar_common(typval_T *argvars, typval_T *rettv, bool skipcc)
{
  const char *s = tv_get_string(&argvars[0]);
  varnumber_T len = 0;
  int (*func_mb_ptr2char_adv)(const char_u **pp);

  func_mb_ptr2char_adv = skipcc ? mb_ptr2char_adv : mb_cptr2char_adv;
  while (*s != NUL) {
    func_mb_ptr2char_adv((const char_u **)&s);
    len++;
  }
  rettv->vval.v_number = len;
}

/// "strcharlen()" function
static void f_strcharlen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  strchar_common(argvars, rettv, true);
}

/// "strchars()" function
static void f_strchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int skipcc = false;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    skipcc = (int)tv_get_bool(&argvars[1]);
  }
  if (skipcc < 0 || skipcc > 1) {
    semsg(_(e_using_number_as_bool_nr), skipcc);
  } else {
    strchar_common(argvars, rettv, skipcc);
  }
}

/// "strdisplaywidth()" function
static void f_strdisplaywidth(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const s = tv_get_string(&argvars[0]);
  int col = 0;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    col = (int)tv_get_number(&argvars[1]);
  }

  rettv->vval.v_number = (varnumber_T)(linetabsize_col(col, (char *)s) - col);
}

/// "strwidth()" function
static void f_strwidth(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const s = tv_get_string(&argvars[0]);

  rettv->vval.v_number = (varnumber_T)mb_string2cells(s);
}

/// "strcharpart()" function
static void f_strcharpart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const p = tv_get_string(&argvars[0]);
  const size_t slen = strlen(p);

  int nbyte = 0;
  bool error = false;
  varnumber_T nchar = tv_get_number_chk(&argvars[1], &error);
  if (!error) {
    if (nchar > 0) {
      while (nchar > 0 && (size_t)nbyte < slen) {
        nbyte += utf_ptr2len(p + nbyte);
        nchar--;
      }
    } else {
      nbyte = (int)nchar;
    }
  }
  int len = 0;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    int charlen = (int)tv_get_number(&argvars[2]);
    while (charlen > 0 && nbyte + len < (int)slen) {
      int off = nbyte + len;

      if (off < 0) {
        len += 1;
      } else {
        len += utf_ptr2len(p + off);
      }
      charlen--;
    }
  } else {
    len = (int)slen - nbyte;    // default: all bytes that are available.
  }

  // Only return the overlap between the specified part and the actual
  // string.
  if (nbyte < 0) {
    len += nbyte;
    nbyte = 0;
  } else if ((size_t)nbyte > slen) {
    nbyte = (int)slen;
  }
  if (len < 0) {
    len = 0;
  } else if (nbyte + len > (int)slen) {
    len = (int)slen - nbyte;
  }

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xstrndup(p + nbyte, (size_t)len);
}

/// "strpart()" function
static void f_strpart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  bool error = false;

  const char *const p = tv_get_string(&argvars[0]);
  const size_t slen = strlen(p);

  varnumber_T n = tv_get_number_chk(&argvars[1], &error);
  varnumber_T len;
  if (error) {
    len = 0;
  } else if (argvars[2].v_type != VAR_UNKNOWN) {
    len = tv_get_number(&argvars[2]);
  } else {
    len = (varnumber_T)slen - n;  // Default len: all bytes that are available.
  }

  // Only return the overlap between the specified part and the actual
  // string.
  if (n < 0) {
    len += n;
    n = 0;
  } else if (n > (varnumber_T)slen) {
    n = (varnumber_T)slen;
  }
  if (len < 0) {
    len = 0;
  } else if (n + len > (varnumber_T)slen) {
    len = (varnumber_T)slen - n;
  }

  if (argvars[2].v_type != VAR_UNKNOWN && argvars[3].v_type != VAR_UNKNOWN) {
    int off;

    // length in characters
    for (off = (int)n; off < (int)slen && len > 0; len--) {
      off += utfc_ptr2len(p + off);
    }
    len = off - n;
  }

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xmemdupz(p + n, (size_t)len);
}

/// "strptime({format}, {timestring})" function
static void f_strptime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char fmt_buf[NUMBUFLEN];
  char str_buf[NUMBUFLEN];

  struct tm tmval = {
    .tm_isdst = -1,
  };
  char *fmt = (char *)tv_get_string_buf(&argvars[0], fmt_buf);
  char *str = (char *)tv_get_string_buf(&argvars[1], str_buf);

  vimconv_T conv = {
    .vc_type = CONV_NONE,
  };
  char *enc = (char *)enc_locale();
  convert_setup(&conv, p_enc, enc);
  if (conv.vc_type != CONV_NONE) {
    fmt = string_convert(&conv, fmt, NULL);
  }
  if (fmt == NULL
      || os_strptime(str, fmt, &tmval) == NULL
      || (rettv->vval.v_number = mktime(&tmval)) == -1) {
    rettv->vval.v_number = 0;
  }
  if (conv.vc_type != CONV_NONE) {
    xfree(fmt);
  }
  convert_setup(&conv, NULL, NULL);
  xfree(enc);
}

/// "strridx()" function
static void f_strridx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf[NUMBUFLEN];
  const char *const needle = tv_get_string_chk(&argvars[1]);
  const char *const haystack = tv_get_string_buf_chk(&argvars[0], buf);

  rettv->vval.v_number = -1;
  if (needle == NULL || haystack == NULL) {
    return;  // Type error; errmsg already given.
  }

  const size_t haystack_len = strlen(haystack);
  ptrdiff_t end_idx;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    // Third argument: upper limit for index.
    end_idx = (ptrdiff_t)tv_get_number_chk(&argvars[2], NULL);
    if (end_idx < 0) {
      return;  // Can never find a match.
    }
  } else {
    end_idx = (ptrdiff_t)haystack_len;
  }

  const char *lastmatch = NULL;
  if (*needle == NUL) {
    // Empty string matches past the end.
    lastmatch = haystack + end_idx;
  } else {
    for (const char *rest = haystack; *rest != NUL; rest++) {
      rest = strstr(rest, needle);
      if (rest == NULL || rest > haystack + end_idx) {
        break;
      }
      lastmatch = rest;
    }
  }

  if (lastmatch != NULL) {
    rettv->vval.v_number = (varnumber_T)(lastmatch - haystack);
  }
}

/// "strtrans()" function
static void f_strtrans(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = transstr(tv_get_string(&argvars[0]), true);
}

/// "submatch()" function
static void f_submatch(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  bool error = false;
  int no = (int)tv_get_number_chk(&argvars[0], &error);
  if (error) {
    return;
  }

  if (no < 0 || no >= NSUBEXP) {
    semsg(_("E935: invalid submatch number: %d"), no);
    return;
  }
  int retList = 0;

  if (argvars[1].v_type != VAR_UNKNOWN) {
    retList = (int)tv_get_number_chk(&argvars[1], &error);
    if (error) {
      return;
    }
  }

  if (retList == 0) {
    rettv->v_type = VAR_STRING;
    rettv->vval.v_string = reg_submatch(no);
  } else {
    rettv->v_type = VAR_LIST;
    rettv->vval.v_list = reg_submatch_list(no);
  }
}

/// "substitute()" function
static void f_substitute(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char patbuf[NUMBUFLEN];
  char subbuf[NUMBUFLEN];
  char flagsbuf[NUMBUFLEN];

  const char *const str = tv_get_string_chk(&argvars[0]);
  const char *const pat = tv_get_string_buf_chk(&argvars[1], patbuf);
  const char *sub = NULL;
  const char *const flg = tv_get_string_buf_chk(&argvars[3], flagsbuf);

  typval_T *expr = NULL;
  if (tv_is_func(argvars[2])) {
    expr = &argvars[2];
  } else {
    sub = tv_get_string_buf_chk(&argvars[2], subbuf);
  }

  rettv->v_type = VAR_STRING;
  if (str == NULL || pat == NULL || (sub == NULL && expr == NULL)
      || flg == NULL) {
    rettv->vval.v_string = NULL;
  } else {
    rettv->vval.v_string = do_string_sub((char *)str, (char *)pat,
                                         (char *)sub, expr, (char *)flg);
  }
}

/// "swapinfo(swap_filename)" function
static void f_swapinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);
  get_b0_dict(tv_get_string(argvars), rettv->vval.v_dict);
}

/// "swapname(expr)" function
static void f_swapname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  buf_T *buf = tv_get_buf(&argvars[0], false);
  if (buf == NULL
      || buf->b_ml.ml_mfp == NULL
      || buf->b_ml.ml_mfp->mf_fname == NULL) {
    rettv->vval.v_string = NULL;
  } else {
    rettv->vval.v_string = xstrdup(buf->b_ml.ml_mfp->mf_fname);
  }
}

/// "synID(lnum, col, trans)" function
static void f_synID(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  // -1 on type error (both)
  const linenr_T lnum = tv_get_lnum(argvars);
  const colnr_T col = (colnr_T)tv_get_number(&argvars[1]) - 1;

  bool transerr = false;
  const int trans = (int)tv_get_number_chk(&argvars[2], &transerr);

  int id = 0;
  if (!transerr && lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count
      && col >= 0 && (size_t)col < strlen(ml_get(lnum))) {
    id = syn_get_id(curwin, lnum, col, trans, NULL, false);
  }

  rettv->vval.v_number = id;
}

/// "synIDattr(id, what [, mode])" function
static void f_synIDattr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const int id = (int)tv_get_number(&argvars[0]);
  const char *const what = tv_get_string(&argvars[1]);
  int modec;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    char modebuf[NUMBUFLEN];
    const char *const mode = tv_get_string_buf(&argvars[2], modebuf);
    modec = TOLOWER_ASC(mode[0]);
    if (modec != 'c' && modec != 'g') {
      modec = 0;  // Replace invalid with current.
    }
  } else if (ui_rgb_attached()) {
    modec = 'g';
  } else {
    modec = 'c';
  }

  const char *p = NULL;
  switch (TOLOWER_ASC(what[0])) {
  case 'b':
    if (TOLOWER_ASC(what[1]) == 'g') {  // bg[#]
      p = highlight_color(id, what, modec);
    } else {  // bold
      p = highlight_has_attr(id, HL_BOLD, modec);
    }
    break;
  case 'f':    // fg[#] or font
    p = highlight_color(id, what, modec);
    break;
  case 'i':
    if (TOLOWER_ASC(what[1]) == 'n') {  // inverse
      p = highlight_has_attr(id, HL_INVERSE, modec);
    } else {  // italic
      p = highlight_has_attr(id, HL_ITALIC, modec);
    }
    break;
  case 'n':
    if (TOLOWER_ASC(what[1]) == 'o') {  // nocombine
      p = highlight_has_attr(id, HL_NOCOMBINE, modec);
    } else {  // name
      p = get_highlight_name_ext(NULL, id - 1, false);
    }
    break;
  case 'r':    // reverse
    p = highlight_has_attr(id, HL_INVERSE, modec);
    break;
  case 's':
    if (TOLOWER_ASC(what[1]) == 'p') {  // sp[#]
      p = highlight_color(id, what, modec);
    } else if (TOLOWER_ASC(what[1]) == 't'
               && TOLOWER_ASC(what[2]) == 'r') {  // strikethrough
      p = highlight_has_attr(id, HL_STRIKETHROUGH, modec);
    } else {  // standout
      p = highlight_has_attr(id, HL_STANDOUT, modec);
    }
    break;
  case 'u':
    if (strlen(what) >= 9) {
      if (TOLOWER_ASC(what[5]) == 'l') {
        // underline
        p = highlight_has_attr(id, HL_UNDERLINE, modec);
      } else if (TOLOWER_ASC(what[5]) != 'd') {
        // undercurl
        p = highlight_has_attr(id, HL_UNDERCURL, modec);
      } else if (TOLOWER_ASC(what[6]) != 'o') {
        // underdashed
        p = highlight_has_attr(id, HL_UNDERDASHED, modec);
      } else if (TOLOWER_ASC(what[7]) == 'u') {
        // underdouble
        p = highlight_has_attr(id, HL_UNDERDOUBLE, modec);
      } else {
        // underdotted
        p = highlight_has_attr(id, HL_UNDERDOTTED, modec);
      }
    } else {
      // ul
      p = highlight_color(id, what, modec);
    }
    break;
  }

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = (char *)(p == NULL ? p : xstrdup(p));
}

/// "synIDtrans(id)" function
static void f_synIDtrans(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int id = (int)tv_get_number(&argvars[0]);

  if (id > 0) {
    id = syn_get_final_id(id);
  } else {
    id = 0;
  }

  rettv->vval.v_number = id;
}

/// "synconcealed(lnum, col)" function
static void f_synconcealed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int syntax_flags = 0;
  int cchar;
  int matchid = 0;
  char_u str[NUMBUFLEN];

  tv_list_set_ret(rettv, NULL);

  // -1 on type error (both)
  const linenr_T lnum = tv_get_lnum(argvars);
  const colnr_T col = (colnr_T)tv_get_number(&argvars[1]) - 1;

  CLEAR_FIELD(str);

  if (lnum >= 1 && lnum <= curbuf->b_ml.ml_line_count && col >= 0
      && (size_t)col <= strlen(ml_get(lnum)) && curwin->w_p_cole > 0) {
    (void)syn_get_id(curwin, lnum, col, false, NULL, false);
    syntax_flags = get_syntax_info(&matchid);

    // get the conceal character
    if ((syntax_flags & HL_CONCEAL) && curwin->w_p_cole < 3) {
      cchar = syn_get_sub_char();
      if (cchar == NUL && curwin->w_p_cole == 1) {
        cchar = (curwin->w_p_lcs_chars.conceal == NUL)
          ? ' '
          : curwin->w_p_lcs_chars.conceal;
      }
      if (cchar != NUL) {
        utf_char2bytes(cchar, (char *)str);
      }
    }
  }

  tv_list_alloc_ret(rettv, 3);
  tv_list_append_number(rettv->vval.v_list, (syntax_flags & HL_CONCEAL) != 0);
  // -1 to auto-determine strlen
  tv_list_append_string(rettv->vval.v_list, (const char *)str, -1);
  tv_list_append_number(rettv->vval.v_list, matchid);
}

/// "synstack(lnum, col)" function
static void f_synstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_set_ret(rettv, NULL);

  // -1 on type error (both)
  const linenr_T lnum = tv_get_lnum(argvars);
  const colnr_T col = (colnr_T)tv_get_number(&argvars[1]) - 1;

  if (lnum >= 1
      && lnum <= curbuf->b_ml.ml_line_count
      && col >= 0
      && (size_t)col <= strlen(ml_get(lnum))) {
    tv_list_alloc_ret(rettv, kListLenMayKnow);
    (void)syn_get_id(curwin, lnum, col, false, NULL, true);

    int id;
    int i = 0;
    while ((id = syn_get_stack_item(i++)) >= 0) {
      tv_list_append_number(rettv->vval.v_list, id);
    }
  }
}

/// f_system - the VimL system() function
static void f_system(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_system_output_as_rettv(argvars, rettv, false);
}

static void f_systemlist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  get_system_output_as_rettv(argvars, rettv, true);
}

/// "tabpagebuflist()" function
static void f_tabpagebuflist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  win_T *wp = NULL;

  if (argvars[0].v_type == VAR_UNKNOWN) {
    wp = firstwin;
  } else {
    tabpage_T *const tp = find_tabpage((int)tv_get_number(&argvars[0]));
    if (tp != NULL) {
      wp = (tp == curtab) ? firstwin : tp->tp_firstwin;
    }
  }
  if (wp != NULL) {
    tv_list_alloc_ret(rettv, kListLenMayKnow);
    while (wp != NULL) {
      tv_list_append_number(rettv->vval.v_list, wp->w_buffer->b_fnum);
      wp = wp->w_next;
    }
  }
}

/// "tagfiles()" function
static void f_tagfiles(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_list_alloc_ret(rettv, kListLenUnknown);
  char *fname = xmalloc(MAXPATHL);

  bool first = true;
  tagname_T tn;
  while (get_tagfname(&tn, first, fname) == OK) {
    tv_list_append_string(rettv->vval.v_list, fname, -1);
    first = false;
  }

  tagname_free(&tn);
  xfree(fname);
}

/// "taglist()" function
static void f_taglist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  const char *const tag_pattern = tv_get_string(&argvars[0]);

  rettv->vval.v_number = false;
  if (*tag_pattern == NUL) {
    return;
  }

  const char *fname = NULL;
  if (argvars[1].v_type != VAR_UNKNOWN) {
    fname = tv_get_string(&argvars[1]);
  }
  (void)get_tags(tv_list_alloc_ret(rettv, kListLenUnknown),
                 (char_u *)tag_pattern, (char_u *)fname);
}

/// "tempname()" function
static void f_tempname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = vim_tempname();
}

/// "termopen(cmd[, cwd])" function
static void f_termopen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (check_secure()) {
    return;
  }

  if (curbuf->b_changed) {
    emsg(_("Can only call this function in an unmodified buffer"));
    return;
  }

  const char *cmd;
  bool executable = true;
  char **argv = tv_to_argv(&argvars[0], &cmd, &executable);
  if (!argv) {
    rettv->vval.v_number = executable ? 0 : -1;
    return;  // Did error message in tv_to_argv.
  }

  if (argvars[1].v_type != VAR_DICT && argvars[1].v_type != VAR_UNKNOWN) {
    // Wrong argument type
    semsg(_(e_invarg2), "expected dictionary");
    shell_free_argv(argv);
    return;
  }

  CallbackReader on_stdout = CALLBACK_READER_INIT,
                 on_stderr = CALLBACK_READER_INIT;
  Callback on_exit = CALLBACK_NONE;
  dict_T *job_opts = NULL;
  const char *cwd = ".";
  dict_T *env = NULL;
  const bool pty = true;
  bool clear_env = false;
  dictitem_T *job_env = NULL;

  if (argvars[1].v_type == VAR_DICT) {
    job_opts = argvars[1].vval.v_dict;

    const char *const new_cwd = tv_dict_get_string(job_opts, "cwd", false);
    if (new_cwd && *new_cwd != NUL) {
      cwd = new_cwd;
      // The new cwd must be a directory.
      if (!os_isdir(cwd)) {
        semsg(_(e_invarg2), "expected valid directory");
        shell_free_argv(argv);
        return;
      }
    }

    job_env = tv_dict_find(job_opts, S_LEN("env"));
    if (job_env && job_env->di_tv.v_type != VAR_DICT) {
      semsg(_(e_invarg2), "env");
      shell_free_argv(argv);
      return;
    }

    clear_env = tv_dict_get_number(job_opts, "clear_env") != 0;

    if (!common_job_callbacks(job_opts, &on_stdout, &on_stderr, &on_exit)) {
      shell_free_argv(argv);
      return;
    }
  }

  env = create_environment(job_env, clear_env, pty, "xterm-256color");

  const bool rpc = false;
  const bool overlapped = false;
  const bool detach = false;
  ChannelStdinMode stdin_mode = kChannelStdinPipe;
  uint16_t term_width = (uint16_t)MAX(0, curwin->w_width_inner - win_col_off(curwin));
  Channel *chan = channel_job_start(argv, on_stdout, on_stderr, on_exit,
                                    pty, rpc, overlapped, detach, stdin_mode,
                                    cwd, term_width, (uint16_t)curwin->w_height_inner,
                                    env, &rettv->vval.v_number);
  if (rettv->vval.v_number <= 0) {
    return;
  }

  int pid = chan->stream.pty.process.pid;

  // "./…" => "/home/foo/…"
  vim_FullName(cwd, (char *)NameBuff, sizeof(NameBuff), false);
  // "/home/foo/…" => "~/…"
  size_t len = home_replace(NULL, (char *)NameBuff, (char *)IObuff, sizeof(IObuff), true);
  // Trim slash.
  if (len != 1 && (IObuff[len - 1] == '\\' || IObuff[len - 1] == '/')) {
    IObuff[len - 1] = '\0';
  }

  if (len == 1 && IObuff[0] == '/') {
    // Avoid ambiguity in the URI when CWD is root directory.
    IObuff[1] = '.';
    IObuff[2] = '\0';
  }

  // Terminal URI: "term://$CWD//$PID:$CMD"
  snprintf((char *)NameBuff, sizeof(NameBuff), "term://%s//%d:%s",
           (char *)IObuff, pid, cmd);
  // at this point the buffer has no terminal instance associated yet, so unset
  // the 'swapfile' option to ensure no swap file will be created
  curbuf->b_p_swf = false;

  apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
  (void)setfname(curbuf, (char *)NameBuff, NULL, true);
  apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);

  // Save the job id and pid in b:terminal_job_{id,pid}
  Error err = ERROR_INIT;
  // deprecated: use 'channel' buffer option
  dict_set_var(curbuf->b_vars, cstr_as_string("terminal_job_id"),
               INTEGER_OBJ((Integer)chan->id), false, false, &err);
  api_clear_error(&err);
  dict_set_var(curbuf->b_vars, cstr_as_string("terminal_job_pid"),
               INTEGER_OBJ(pid), false, false, &err);
  api_clear_error(&err);

  channel_terminal_open(curbuf, chan);
  channel_create_event(chan, NULL);
}

/// "timer_info([timer])" function
static void f_timer_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_UNKNOWN) {
    if (argvars[0].v_type != VAR_NUMBER) {
      emsg(_(e_number_exp));
      return;
    }
    tv_list_alloc_ret(rettv, 1);
    timer_T *timer = find_timer_by_nr(tv_get_number(&argvars[0]));
    if (timer != NULL && !timer->stopped) {
      add_timer_info(rettv, timer);
    }
  } else {
    add_timer_info_all(rettv);
  }
}

/// "timer_pause(timer, paused)" function
static void f_timer_pause(typval_T *argvars, typval_T *unused, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_NUMBER) {
    emsg(_(e_number_exp));
    return;
  }
  int paused = (bool)tv_get_number(&argvars[1]);
  timer_T *timer = find_timer_by_nr(tv_get_number(&argvars[0]));
  if (timer != NULL) {
    if (!timer->paused && paused) {
      time_watcher_stop(&timer->tw);
    } else if (timer->paused && !paused) {
      time_watcher_start(&timer->tw, timer_due_cb, (uint64_t)timer->timeout,
                         (uint64_t)timer->timeout);
    }
    timer->paused = paused;
  }
}

/// "timer_start(timeout, callback, opts)" function
static void f_timer_start(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int repeat = 1;

  rettv->vval.v_number = -1;
  if (check_secure()) {
    return;
  }

  if (argvars[2].v_type != VAR_UNKNOWN) {
    dict_T *dict = argvars[2].vval.v_dict;
    if (argvars[2].v_type != VAR_DICT || dict == NULL) {
      semsg(_(e_invarg2), tv_get_string(&argvars[2]));
      return;
    }
    dictitem_T *const di = tv_dict_find(dict, S_LEN("repeat"));
    if (di != NULL) {
      repeat = (int)tv_get_number(&di->di_tv);
      if (repeat == 0) {
        repeat = 1;
      }
    }
  }

  Callback callback;
  if (!callback_from_typval(&callback, &argvars[1])) {
    return;
  }
  rettv->vval.v_number = (varnumber_T)timer_start(tv_get_number(&argvars[0]), repeat, &callback);
}

/// "timer_stop(timerid)" function
static void f_timer_stop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (argvars[0].v_type != VAR_NUMBER) {
    emsg(_(e_number_exp));
    return;
  }

  timer_T *timer = find_timer_by_nr(tv_get_number(&argvars[0]));
  if (timer == NULL) {
    return;
  }

  timer_stop(timer);
}

static void f_timer_stopall(typval_T *argvars, typval_T *unused, EvalFuncData fptr)
{
  timer_stop_all();
}

/// "tolower(string)" function
static void f_tolower(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = strcase_save(tv_get_string(&argvars[0]), false);
}

/// "toupper(string)" function
static void f_toupper(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = strcase_save(tv_get_string(&argvars[0]), true);
}

/// "tr(string, fromstr, tostr)" function
static void f_tr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf[NUMBUFLEN];
  char buf2[NUMBUFLEN];

  const char *in_str = tv_get_string(&argvars[0]);
  const char *fromstr = tv_get_string_buf_chk(&argvars[1], buf);
  const char *tostr = tv_get_string_buf_chk(&argvars[2], buf2);

  // Default return value: empty string.
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
  if (fromstr == NULL || tostr == NULL) {
    return;  // Type error; errmsg already given.
  }
  garray_T ga;
  ga_init(&ga, (int)sizeof(char), 80);

  // fromstr and tostr have to contain the same number of chars.
  bool first = true;
  while (*in_str != NUL) {
    const char *cpstr = in_str;
    const int inlen = utfc_ptr2len(in_str);
    int cplen = inlen;
    int idx = 0;
    int fromlen;
    for (const char *p = fromstr; *p != NUL; p += fromlen) {
      fromlen = utfc_ptr2len(p);
      if (fromlen == inlen && strncmp(in_str, p, (size_t)inlen) == 0) {
        int tolen;
        for (p = tostr; *p != NUL; p += tolen) {
          tolen = utfc_ptr2len(p);
          if (idx-- == 0) {
            cplen = tolen;
            cpstr = (char *)p;
            break;
          }
        }
        if (*p == NUL) {  // tostr is shorter than fromstr.
          goto error;
        }
        break;
      }
      idx++;
    }

    if (first && cpstr == in_str) {
      // Check that fromstr and tostr have the same number of
      // (multi-byte) characters.  Done only once when a character
      // of in_str doesn't appear in fromstr.
      first = false;
      int tolen;
      for (const char *p = tostr; *p != NUL; p += tolen) {
        tolen = utfc_ptr2len(p);
        idx--;
      }
      if (idx != 0) {
        goto error;
      }
    }

    ga_grow(&ga, cplen);
    memmove((char *)ga.ga_data + ga.ga_len, cpstr, (size_t)cplen);
    ga.ga_len += cplen;

    in_str += inlen;
  }

  // add a terminating NUL
  ga_append(&ga, NUL);

  rettv->vval.v_string = ga.ga_data;
  return;
error:
  semsg(_(e_invarg2), fromstr);
  ga_clear(&ga);
}

/// "trim({expr})" function
static void f_trim(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char buf1[NUMBUFLEN];
  char buf2[NUMBUFLEN];
  const char *head = tv_get_string_buf_chk(&argvars[0], buf1);
  const char *mask = NULL;
  const char *prev;
  const char *p;
  int dir = 0;

  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = NULL;
  if (head == NULL) {
    return;
  }

  if (argvars[1].v_type != VAR_UNKNOWN && argvars[1].v_type != VAR_STRING) {
    semsg(_(e_invarg2), tv_get_string(&argvars[1]));
    return;
  }

  if (argvars[1].v_type == VAR_STRING) {
    mask = tv_get_string_buf_chk(&argvars[1], buf2);
    if (argvars[2].v_type != VAR_UNKNOWN) {
      bool error = false;
      // leading or trailing characters to trim
      dir = (int)tv_get_number_chk(&argvars[2], &error);
      if (error) {
        return;
      }
      if (dir < 0 || dir > 2) {
        semsg(_(e_invarg2), tv_get_string(&argvars[2]));
        return;
      }
    }
  }

  int c1;
  if (dir == 0 || dir == 1) {
    // Trim leading characters
    while (*head != NUL) {
      c1 = utf_ptr2char((char *)head);
      if (mask == NULL) {
        if (c1 > ' ' && c1 != 0xa0) {
          break;
        }
      } else {
        for (p = mask; *p != NUL; MB_PTR_ADV(p)) {
          if (c1 == utf_ptr2char((char *)p)) {
            break;
          }
        }
        if (*p == NUL) {
          break;
        }
      }
      MB_PTR_ADV(head);
    }
  }

  const char *tail = head + strlen(head);
  if (dir == 0 || dir == 2) {
    // Trim trailing characters
    for (; tail > head; tail = prev) {
      prev = tail;
      MB_PTR_BACK(head, prev);
      c1 = utf_ptr2char((char *)prev);
      if (mask == NULL) {
        if (c1 > ' ' && c1 != 0xa0) {
          break;
        }
      } else {
        for (p = mask; *p != NUL; MB_PTR_ADV(p)) {
          if (c1 == utf_ptr2char((char *)p)) {
            break;
          }
        }
        if (*p == NUL) {
          break;
        }
      }
    }
  }
  rettv->vval.v_string = xstrnsave(head, (size_t)(tail - head));
}

/// "type(expr)" function
static void f_type(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  int n = -1;

  switch (argvars[0].v_type) {
  case VAR_NUMBER:
    n = VAR_TYPE_NUMBER; break;
  case VAR_STRING:
    n = VAR_TYPE_STRING; break;
  case VAR_PARTIAL:
  case VAR_FUNC:
    n = VAR_TYPE_FUNC; break;
  case VAR_LIST:
    n = VAR_TYPE_LIST; break;
  case VAR_DICT:
    n = VAR_TYPE_DICT; break;
  case VAR_FLOAT:
    n = VAR_TYPE_FLOAT; break;
  case VAR_BOOL:
    n = VAR_TYPE_BOOL; break;
  case VAR_SPECIAL:
    n = VAR_TYPE_SPECIAL; break;
  case VAR_BLOB:
    n = VAR_TYPE_BLOB; break;
  case VAR_UNKNOWN:
    internal_error("f_type(UNKNOWN)");
    break;
  }
  rettv->vval.v_number = n;
}

/// "undofile(name)" function
static void f_undofile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  const char *const fname = tv_get_string(&argvars[0]);

  if (*fname == NUL) {
    // If there is no file name there will be no undo file.
    rettv->vval.v_string = NULL;
  } else {
    char *ffname = FullName_save(fname, true);

    if (ffname != NULL) {
      rettv->vval.v_string = u_get_undo_file_name(ffname, false);
    }
    xfree(ffname);
  }
}

/// "undotree()" function
static void f_undotree(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);

  dict_T *dict = rettv->vval.v_dict;

  tv_dict_add_nr(dict, S_LEN("synced"), (varnumber_T)curbuf->b_u_synced);
  tv_dict_add_nr(dict, S_LEN("seq_last"), (varnumber_T)curbuf->b_u_seq_last);
  tv_dict_add_nr(dict, S_LEN("save_last"),
                 (varnumber_T)curbuf->b_u_save_nr_last);
  tv_dict_add_nr(dict, S_LEN("seq_cur"), (varnumber_T)curbuf->b_u_seq_cur);
  tv_dict_add_nr(dict, S_LEN("time_cur"), (varnumber_T)curbuf->b_u_time_cur);
  tv_dict_add_nr(dict, S_LEN("save_cur"), (varnumber_T)curbuf->b_u_save_nr_cur);

  tv_dict_add_list(dict, S_LEN("entries"), u_eval_tree(curbuf->b_u_oldhead));
}

/// "virtcol(string)" function
static void f_virtcol(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  colnr_T vcol = 0;
  int fnum = curbuf->b_fnum;

  pos_T *fp = var2fpos(&argvars[0], false, &fnum, false);
  if (fp != NULL && fp->lnum <= curbuf->b_ml.ml_line_count
      && fnum == curbuf->b_fnum) {
    // Limit the column to a valid value, getvvcol() doesn't check.
    if (fp->col < 0) {
      fp->col = 0;
    } else {
      const size_t len = strlen(ml_get(fp->lnum));
      if (fp->col > (colnr_T)len) {
        fp->col = (colnr_T)len;
      }
    }
    getvvcol(curwin, fp, NULL, NULL, &vcol);
    vcol++;
  }

  rettv->vval.v_number = vcol;
}

/// "visualmode()" function
static void f_visualmode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  char str[2];

  rettv->v_type = VAR_STRING;
  str[0] = (char)curbuf->b_visual_mode_eval;
  str[1] = NUL;
  rettv->vval.v_string = xstrdup(str);

  // A non-zero number or non-empty string argument: reset mode.
  if (non_zero_arg(&argvars[0])) {
    curbuf->b_visual_mode_eval = NUL;
  }
}

/// "wildmenumode()" function
static void f_wildmenumode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  if (wild_menu_showing || ((State & MODE_CMDLINE) && cmdline_pum_active())) {
    rettv->vval.v_number = 1;
  }
}

/// "windowsversion()" function
static void f_windowsversion(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->v_type = VAR_STRING;
  rettv->vval.v_string = xstrdup(windowsVersion);
}

/// "wordcount()" function
static void f_wordcount(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  tv_dict_alloc_ret(rettv);
  cursor_pos_info(rettv->vval.v_dict);
}

/// "writefile()" function
static void f_writefile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = -1;

  if (check_secure()) {
    return;
  }

  if (argvars[0].v_type == VAR_LIST) {
    TV_LIST_ITER_CONST(argvars[0].vval.v_list, li, {
      if (!tv_check_str_or_nr(TV_LIST_ITEM_TV(li))) {
        return;
      }
    });
  } else if (argvars[0].v_type != VAR_BLOB) {
    semsg(_(e_invarg2),
          _("writefile() first argument must be a List or a Blob"));
    return;
  }

  bool binary = false;
  bool append = false;
  bool do_fsync = !!p_fs;
  bool mkdir_p = false;
  if (argvars[2].v_type != VAR_UNKNOWN) {
    const char *const flags = tv_get_string_chk(&argvars[2]);
    if (flags == NULL) {
      return;
    }
    for (const char *p = flags; *p; p++) {
      switch (*p) {
      case 'b':
        binary = true; break;
      case 'a':
        append = true; break;
      case 's':
        do_fsync = true; break;
      case 'S':
        do_fsync = false; break;
      case 'p':
        mkdir_p = true; break;
      default:
        // Using %s, p and not %c, *p to preserve multibyte characters
        semsg(_("E5060: Unknown flag: %s"), p);
        return;
      }
    }
  }

  char buf[NUMBUFLEN];
  const char *const fname = tv_get_string_buf_chk(&argvars[1], buf);
  if (fname == NULL) {
    return;
  }
  FileDescriptor fp;
  int error;
  if (*fname == NUL) {
    emsg(_("E482: Can't open file with an empty name"));
  } else if ((error = file_open(&fp, fname,
                                ((append ? kFileAppend : kFileTruncate)
                                 | (mkdir_p ? kFileMkDir : kFileCreate)
                                 | kFileCreate), 0666)) != 0) {
    semsg(_("E482: Can't open file %s for writing: %s"),
          fname, os_strerror(error));
  } else {
    bool write_ok;
    if (argvars[0].v_type == VAR_BLOB) {
      write_ok = write_blob(&fp, argvars[0].vval.v_blob);
    } else {
      write_ok = write_list(&fp, argvars[0].vval.v_list, binary);
    }
    if (write_ok) {
      rettv->vval.v_number = 0;
    }
    if ((error = file_close(&fp, do_fsync)) != 0) {
      semsg(_("E80: Error when closing file %s: %s"),
            fname, os_strerror(error));
    }
  }
}

/// "xor(expr, expr)" function
static void f_xor(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
{
  rettv->vval.v_number = tv_get_number_chk(&argvars[0], NULL)
                         ^ tv_get_number_chk(&argvars[1], NULL);
}