Merge pull request #19931 from bfredl/scopedhl

feat(highlight)!: use scoped @foo.bar.special groups for tree-sitter highlight

3 files changed, 124 insertions, 113 deletions

diff --git a/runtime/doc/treesitter.txt b/runtime/doc/treesitter.txt
index c80d8f4479..2c6c9e4ed8 100644
--- a/runtime/doc/treesitter.txt
+++ b/runtime/doc/treesitter.txt
@@ -323,16 +323,34 @@ for a buffer with this code: >
     local query2 = [[ ... ]]
     highlighter:set_query(query2)
 
-As mentioned above the supported predicate is currently only `eq?`. `match?`
-predicates behave like matching always fails. As an addition a capture which
-begin with an upper-case letter like `@WarningMsg` will map directly to this
-highlight group, if defined. Also if the predicate begins with upper-case and
-contains a dot only the part before the first will be interpreted as the
-highlight group. As an example, this warns of a binary expression with two
+
+                                             *lua-treesitter-highlight-groups*
+The capture names, with `@` included, are directly usable as highlight groups.
+A fallback system is implemented, so that more specific groups fallback to
+more generic ones. For instance, in a language that has separate doc
+comments, `@comment.doc` could be used. If this group is not defined, the
+highlighting for an ordinary `@comment` is used. This way, existing color
+schemes already work out of the box, but it is possible to add
+more specific variants for queries that make them available.
+
+As an additional rule, captures highlights can always be specialized by
+language, by appending the language name after an additional dot. For
+instance, to highlight comments differently per language: >
+
+    hi @comment.c guifg=Blue
+    hi @comment.lua @guifg=DarkBlue
+    hi link @comment.doc.java String
+<
+It is possible to use custom highlight groups. As an example, if we
+define the `@warning` group: >
+
+    hi link @warning WarningMsg
+<
+the following query warns of a binary expression with two
 identical identifiers, highlighting both as |hl-WarningMsg|: >
 
-    ((binary_expression left: (identifier) @WarningMsg.left right: (identifier) @WarningMsg.right)
-     (eq? @WarningMsg.left @WarningMsg.right))
+    ((binary_expression left: (identifier) @warning.left right: (identifier) @warning.right)
+     (eq? @warning.left @warning.right))
 <
 Treesitter Highlighting Priority            *lua-treesitter-highlight-priority*
 
@@ -352,6 +370,18 @@ attribute: >
 ==============================================================================
 Lua module: vim.treesitter                               *lua-treesitter-core*
 
+                                                  *get_captures_at_position()*
+get_captures_at_position({bufnr}, {row}, {col})
+    Gets a list of captures for a given cursor position
+
+    Parameters: ~
+        {bufnr}  (number) The buffer number
+        {row}    (number) The position row
+        {col}    (number) The position column
+
+    Return: ~
+        (table) A table of captures
+
 get_node_range({node_or_range})                             *get_node_range()*
     Get the node's range or unpack a range table
 
@@ -393,6 +423,14 @@ is_ancestor({dest}, {source})                                  *is_ancestor()*
     Return: ~
         (boolean) True if dest is an ancestor of source
 
+is_in_node_range({node}, {line}, {col})                   *is_in_node_range()*
+    Determines whether (line, col) position is in node range
+
+    Parameters: ~
+        {node}  Node defining the range
+        {line}  A line (0-based)
+        {col}   A column (0-based)
+
 node_contains({node}, {range})                               *node_contains()*
     Determines if a node contains a range
 
diff --git a/runtime/lua/vim/treesitter.lua b/runtime/lua/vim/treesitter.lua
index 82d41070ee..6431162799 100644
--- a/runtime/lua/vim/treesitter.lua
+++ b/runtime/lua/vim/treesitter.lua
@@ -154,6 +154,28 @@ function M.get_node_range(node_or_range)
   end
 end
 
+---Determines whether (line, col) position is in node range
+---
+---@param node Node defining the range
+---@param line A line (0-based)
+---@param col A column (0-based)
+function M.is_in_node_range(node, line, col)
+  local start_line, start_col, end_line, end_col = M.get_node_range(node)
+  if line >= start_line and line <= end_line then
+    if line == start_line and line == end_line then
+      return col >= start_col and col < end_col
+    elseif line == start_line then
+      return col >= start_col
+    elseif line == end_line then
+      return col < end_col
+    else
+      return true
+    end
+  else
+    return false
+  end
+end
+
 ---Determines if a node contains a range
 ---@param node table The node
 ---@param range table The range
@@ -167,4 +189,56 @@ function M.node_contains(node, range)
   return start_fits and end_fits
 end
 
+---Gets a list of captures for a given cursor position
+---@param bufnr number The buffer number
+---@param row number The position row
+---@param col number The position column
+---
+---@returns (table) A table of captures
+function M.get_captures_at_position(bufnr, row, col)
+  if bufnr == 0 then
+    bufnr = a.nvim_get_current_buf()
+  end
+  local buf_highlighter = M.highlighter.active[bufnr]
+
+  if not buf_highlighter then
+    return {}
+  end
+
+  local matches = {}
+
+  buf_highlighter.tree:for_each_tree(function(tstree, tree)
+    if not tstree then
+      return
+    end
+
+    local root = tstree:root()
+    local root_start_row, _, root_end_row, _ = root:range()
+
+    -- Only worry about trees within the line range
+    if root_start_row > row or root_end_row < row then
+      return
+    end
+
+    local q = buf_highlighter:get_query(tree:lang())
+
+    -- Some injected languages may not have highlight queries.
+    if not q:query() then
+      return
+    end
+
+    local iter = q:query():iter_captures(root, buf_highlighter.bufnr, row, row + 1)
+
+    for capture, node, metadata in iter do
+      if M.is_in_node_range(node, row, col) then
+        local c = q._query.captures[capture] -- name of the capture in the query
+        if c ~= nil then
+          table.insert(matches, { capture = c, priority = metadata.priority })
+        end
+      end
+    end
+  end, true)
+  return matches
+end
+
 return M
diff --git a/runtime/lua/vim/treesitter/highlighter.lua b/runtime/lua/vim/treesitter/highlighter.lua
index e27a5fa9c3..1f242b0fdd 100644
--- a/runtime/lua/vim/treesitter/highlighter.lua
+++ b/runtime/lua/vim/treesitter/highlighter.lua
@@ -12,105 +12,18 @@ TSHighlighterQuery.__index = TSHighlighterQuery
 
 local ns = a.nvim_create_namespace('treesitter/highlighter')
 
-local _default_highlights = {}
-local _link_default_highlight_once = function(from, to)
-  if not _default_highlights[from] then
-    _default_highlights[from] = true
-    a.nvim_set_hl(0, from, { link = to, default = true })
-  end
-
-  return from
-end
-
--- If @definition.special does not exist use @definition instead
-local subcapture_fallback = {
-  __index = function(self, capture)
-    local rtn
-    local shortened = capture
-    while not rtn and shortened do
-      shortened = shortened:match('(.*)%.')
-      rtn = shortened and rawget(self, shortened)
-    end
-    rawset(self, capture, rtn or '__notfound')
-    return rtn
-  end,
-}
-
-TSHighlighter.hl_map = setmetatable({
-  ['error'] = 'Error',
-  ['text.underline'] = 'Underlined',
-  ['todo'] = 'Todo',
-  ['debug'] = 'Debug',
-
-  -- Miscs
-  ['comment'] = 'Comment',
-  ['punctuation.delimiter'] = 'Delimiter',
-  ['punctuation.bracket'] = 'Delimiter',
-  ['punctuation.special'] = 'Delimiter',
-
-  -- Constants
-  ['constant'] = 'Constant',
-  ['constant.builtin'] = 'Special',
-  ['constant.macro'] = 'Define',
-  ['define'] = 'Define',
-  ['macro'] = 'Macro',
-  ['string'] = 'String',
-  ['string.regex'] = 'String',
-  ['string.escape'] = 'SpecialChar',
-  ['character'] = 'Character',
-  ['character.special'] = 'SpecialChar',
-  ['number'] = 'Number',
-  ['boolean'] = 'Boolean',
-  ['float'] = 'Float',
-
-  -- Functions
-  ['function'] = 'Function',
-  ['function.special'] = 'Function',
-  ['function.builtin'] = 'Special',
-  ['function.macro'] = 'Macro',
-  ['parameter'] = 'Identifier',
-  ['method'] = 'Function',
-  ['field'] = 'Identifier',
-  ['property'] = 'Identifier',
-  ['constructor'] = 'Special',
-
-  -- Keywords
-  ['conditional'] = 'Conditional',
-  ['repeat'] = 'Repeat',
-  ['label'] = 'Label',
-  ['operator'] = 'Operator',
-  ['keyword'] = 'Keyword',
-  ['exception'] = 'Exception',
-
-  ['type'] = 'Type',
-  ['type.builtin'] = 'Type',
-  ['type.qualifier'] = 'Type',
-  ['type.definition'] = 'Typedef',
-  ['storageclass'] = 'StorageClass',
-  ['structure'] = 'Structure',
-  ['include'] = 'Include',
-  ['preproc'] = 'PreProc',
-}, subcapture_fallback)
-
----@private
-local function is_highlight_name(capture_name)
-  local firstc = string.sub(capture_name, 1, 1)
-  return firstc ~= string.lower(firstc)
-end
-
 ---@private
 function TSHighlighterQuery.new(lang, query_string)
   local self = setmetatable({}, { __index = TSHighlighterQuery })
 
   self.hl_cache = setmetatable({}, {
     __index = function(table, capture)
-      local hl, is_vim_highlight = self:_get_hl_from_capture(capture)
-      if not is_vim_highlight then
-        hl = _link_default_highlight_once(lang .. hl, hl)
+      local name = self._query.captures[capture]
+      local id = 0
+      if not vim.startswith(name, '_') then
+        id = a.nvim_get_hl_id_by_name('@' .. name .. '.' .. lang)
       end
 
-      local id = a.nvim_get_hl_id_by_name(hl)
-
       rawset(table, capture, id)
       return id
     end,
@@ -130,20 +43,6 @@ function TSHighlighterQuery:query()
   return self._query
 end
 
----@private
---- Get the hl from capture.
---- Returns a tuple { highlight_name: string, is_builtin: bool }
-function TSHighlighterQuery:_get_hl_from_capture(capture)
-  local name = self._query.captures[capture]
-
-  if is_highlight_name(name) then
-    -- From "Normal.left" only keep "Normal"
-    return vim.split(name, '.', true)[1], true
-  else
-    return TSHighlighter.hl_map[name] or 0, false
-  end
-end
-
 --- Creates a new highlighter using @param tree
 ---
 ---@param tree The language tree to use for highlighting