1 files changed, 73 insertions, 0 deletions
diff --git a/runtime/lua/vim/treesitter.lua b/runtime/lua/vim/treesitter.lua
new file mode 100644
index 0000000000..e0202927bb
--- /dev/null
+++ b/runtime/lua/vim/treesitter.lua
@@ -0,0 +1,73 @@
+local a = vim.api
+
+-- TODO(bfredl): currently we retain parsers for the lifetime of the buffer.
+-- Consider use weak references to release parser if all plugins are done with
+-- it.
+local parsers = {}
+
+local Parser = {}
+Parser.__index = Parser
+
+function Parser:parse()
+  if self.valid then
+    return self.tree
+  end
+  self.tree = self._parser:parse_buf(self.bufnr)
+  self.valid = true
+  return self.tree
+end
+
+function Parser:_on_lines(bufnr, _, start_row, old_stop_row, stop_row, old_byte_size)
+  local start_byte = a.nvim_buf_get_offset(bufnr,start_row)
+  local stop_byte = a.nvim_buf_get_offset(bufnr,stop_row)
+  local old_stop_byte = start_byte + old_byte_size
+  self._parser:edit(start_byte,old_stop_byte,stop_byte,
+                    start_row,0,old_stop_row,0,stop_row,0)
+  self.valid = false
+end
+
+local module = {
+  add_language=vim._ts_add_language,
+  inspect_language=vim._ts_inspect_language,
+}
+
+function module.create_parser(bufnr, ft, id)
+  if bufnr == 0 then
+    bufnr = a.nvim_get_current_buf()
+  end
+  local self = setmetatable({bufnr=bufnr, valid=false}, Parser)
+  self._parser = vim._create_ts_parser(ft)
+  self:parse()
+    -- TODO(bfredl): use weakref to self, so that the parser is free'd is no plugin is
+    -- using it.
+  local function lines_cb(_, ...)
+    return self:_on_lines(...)
+  end
+  local detach_cb = nil
+  if id ~= nil then
+    detach_cb = function()
+      if parsers[id] == self then
+        parsers[id] = nil
+      end
+    end
+  end
+  a.nvim_buf_attach(self.bufnr, false, {on_lines=lines_cb, on_detach=detach_cb})
+  return self
+end
+
+function module.get_parser(bufnr, ft)
+  if bufnr == nil or bufnr == 0 then
+    bufnr = a.nvim_get_current_buf()
+  end
+  if ft == nil then
+    ft = a.nvim_buf_get_option(bufnr, "filetype")
+  end
+  local id = tostring(bufnr)..'_'..ft
+
+  if parsers[id] == nil then
+    parsers[id] = module.create_parser(bufnr, ft, id)
+  end
+  return parsers[id]
+end
+
+return module