fix(lsp): support v:count in selection_range() #34551

Co-authored-by: Yi Ming <ofseed@foxmail.com>

runtime/doc/lsp.txt

@@ -1839,11 +1839,11 @@ rename({new_name}, {opts})                              *vim.lsp.buf.rename()*
 
 selection_range({direction})                   *vim.lsp.buf.selection_range()*
     Perform an incremental selection at the cursor position based on ranges
-    given by the LSP. The `direction` parameter specifies whether the
-    selection should head inward or outward.
+    given by the LSP. The `direction` parameter specifies the number of times
+    to expand the selection. Negative values will shrink the selection.
 
     Parameters: ~
-      • {direction}  (`'inner'|'outer'`)
+      • {direction}  (`integer`)
 
 signature_help({config})                        *vim.lsp.buf.signature_help()*
     Displays signature information about the symbol under the cursor in a

runtime/doc/news.txt

@@ -24,7 +24,8 @@ EXPERIMENTS
 
 LSP
 
-• todo
+• |vim.lsp.buf.selection_range()| now accepts an integer which specifies its
+  direction, rather than a string `'outer'` or `'inner'`.
 
 OPTIONS
 

runtime/lua/vim/_defaults.lua

@@ -210,12 +210,12 @@ do
     end, { desc = 'vim.lsp.buf.implementation()' })
 
     vim.keymap.set('x', 'an', function()
-      vim.lsp.buf.selection_range('outer')
-    end, { desc = "vim.lsp.buf.selection_range('outer')" })
+      vim.lsp.buf.selection_range(vim.v.count1)
+    end, { desc = 'vim.lsp.buf.selection_range(vim.v.count1)' })
 
     vim.keymap.set('x', 'in', function()
-      vim.lsp.buf.selection_range('inner')
-    end, { desc = "vim.lsp.buf.selection_range('inner')" })
+      vim.lsp.buf.selection_range(-vim.v.count1)
+    end, { desc = 'vim.lsp.buf.selection_range(-vim.v.count1)' })
 
     vim.keymap.set('n', 'gO', function()
       vim.lsp.buf.document_symbol()

runtime/lua/vim/lsp/buf.lua

@@ -1413,20 +1413,16 @@ local function is_empty(range)
 end
 
 --- Perform an incremental selection at the cursor position based on ranges given by the LSP. The
---- `direction` parameter specifies whether the selection should head inward or outward.
+--- `direction` parameter specifies the number of times to expand the selection. Negative values
+--- will shrink the selection.
 ---
---- @param direction 'inner' | 'outer'
+--- @param direction integer
 function M.selection_range(direction)
-  validate('direction', direction, function(v)
-    return v == 'inner' or v == 'outer'
-  end)
+  validate('direction', direction, 'number')
 
   if selection_ranges then
-    local offset = direction == 'outer' and 1 or -1
-    local new_index = selection_ranges.index + offset
-    if new_index <= #selection_ranges.ranges and new_index >= 1 then
-      selection_ranges.index = new_index
-    end
+    local new_index = selection_ranges.index + direction
+    selection_ranges.index = math.min(#selection_ranges.ranges, math.max(1, new_index))
 
     select_range(selection_ranges.ranges[selection_ranges.index])
     return
@@ -1498,8 +1494,9 @@ function M.selection_range(direction)
       })
 
       if #ranges > 0 then
-        selection_ranges = { index = 1, ranges = ranges }
-        select_range(ranges[1])
+        local index = math.min(#ranges, math.max(1, direction))
+        selection_ranges = { index = index, ranges = ranges }
+        select_range(ranges[index])
       end
     end
   )