Use keywords to represent auxiliary (invisible) node types

Author: ubolonton

CHANGELOG.md

@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
 - Fixed some invalid query patterns [causing SIGABRT](https://github.com/ubolonton/emacs-tree-sitter/issues/125), by upgrading `tree-sitter` crate.
+- Used keywords to represent auxiliary (invisible) node types. For example: `:end`, `:_expression`.
 
 ## [0.15.0] - 2021-03-15
 - Upgraded `tree-sitter` crate to 0.19.3, which:

core/src/lang.rs

@@ -107,7 +107,9 @@ fn _load_language(file: String, symbol_name: String, lang_symbol: Value) -> Resu
     }
     let node_types = (0..language.node_kind_count() as u16).map(|id| {
         let type_str = language.node_kind_for_id(id).expect("Failed to get node type for id");
-        let value = if language.node_kind_is_named(id) {
+        let value = if !language.node_kind_is_visible(id) {
+            env.intern(&format!(":{}", type_str)).expect("Failed to intern keyword for node type")
+        } else if language.node_kind_is_named(id) {
             env.intern(type_str).expect("Failed to intern symbol for node type")
         } else {
             type_str.into_lisp(env).expect("Failed to make string for node type")
@@ -147,6 +149,7 @@ fn _lang_load_file(language: Language) -> Result<&'static String> {
 ///
 /// For named nodes, the node type is a symbol. For example: 'identifier, 'block.
 /// For anonymous nodes, the node type is a string. For example: "if", "else".
+/// For auxiliary (invisible) nodes, the node type is a keyword. For example: :end, :_expression.
 #[defun]
 fn lang_node_type(language: Language, type_id: u16) -> Result<Option<&'static GlobalRef>> {
     Ok(language.info().node_type(type_id))

lisp/tree-sitter-tests.el

@@ -126,7 +126,7 @@ If RESET is non-nil, also do another full parse and check again."
                          (tsc-lang-node-type language))
                        node-type))))
     (ert-info ("0 should be the special node type \"end\"")
-      (should (equal "end" (format "%s" (tsc-lang-node-type language 0)))))
+      (should (equal :end (tsc-lang-node-type language 0))))
     (ert-info ("Node type IDs should be from 0 to type count minus 1")
       (should-not (null (tsc-lang-node-type language 1)))
       (should-not (null (tsc-lang-node-type language (- type-count 1))))