feat: syntax highlighting

lua/nvim-treesitter.lua

@@ -3,6 +3,7 @@ local parsers = require'nvim-treesitter.parsers'
 local configs = require 'nvim-treesitter.configs'
 local install = require'nvim-treesitter.install'
 local locals = require'nvim-treesitter.locals'
+local highlight = require'nvim-treesitter.highlight'
 
 local M = {}
 
@@ -14,6 +15,8 @@ end
 -- this is the main interface through the plugin
 function M.setup(lang)
   if parsers.has_parser(lang) then
+    local autocmd = "autocmd NvimTreesitter FileType %s lua require'nvim-treesitter.highlight'.setup()"
+    api.nvim_command(string.format(autocmd, lang))
   end
 end
 

lua/nvim-treesitter/highlight.lua

@@ -0,0 +1,17 @@
+local api = vim.api
+local queries = require'nvim-treesitter.query'
+local ts = vim.treesitter
+
+local M = {}
+
+function M.setup(bufnr, ft)
+  local buf = bufnr or api.nvim_get_current_buf()
+  local ft = ft or api.nvim_buf_get_option(buf, 'ft')
+
+  local query = queries.get_query(ft, "highlights")
+  if not query then return end
+
+  ts.TSHighlighter.new(query, buf, ft)
+end
+
+return M

lua/nvim-treesitter/query.lua

@@ -62,7 +62,7 @@ function M.iter_prepared_matches(query, qnode, bufnr, start_row, end_row)
       local preds = query.info.patterns[pattern]
       if preds then
         for _, pred in pairs(preds) do
-          if pred[1] == "set!" and pred[2] ~= nil then
+          if pred[1] == "set!" and type(pred[2]) == "string" then
             insert_to_path(prepared_match, split(pred[2]), pred[3])
           end
         end

queries/lua/highlights.scm

@@ -0,0 +1,36 @@
+;;; Highlighting for lua
+
+;;; Builtins
+;; Keywords
+"local" @keyword
+"if" @keyword
+"then" @keyword
+"else" @keyword
+"elseif" @keyword
+"end" @keyword
+"return" @keyword
+"do" @keyword
+"while" @keyword
+"repeat" @keyword
+"for" @keyword
+
+;; Operators
+"~=" @operator
+"==" @operator
+"not" @operator
+"and" @operator
+"or" @operator
+
+;; Constants
+(false) @constant
+(true) @constant
+(nil) @constant
+
+;; Nodes
+(function "function" @function "end" @function)
+(comment) @comment
+(string) @string
+(number) @constant
+
+;; Error
+(ERROR) @Error