enh(parser) use negative look-ahead for beginKeywords

CHANGES.md

@@ -1,5 +1,9 @@
 ## Version 10.4.0 (work in process)
 
+Parser:
+
+- enh(parser) use negative look-ahead for `beginKeywords` support (#2813) [Josh Goebel][]
+
 Language Improvements:
 
 - enh(julia) Update keyword lists for Julia 1.x (#2781) [Fredrik Ekre][]

src/lib/mode_compiler.js

@@ -240,18 +240,17 @@ export function compileLanguage(language) {
 
   // TODO: We need negative look-behind support to do this properly
   /**
-   * Skip a match if it has a preceding or trailing dot
+   * Skip a match if it has a preceding dot
    *
    * This is used for `beginKeywords` to prevent matching expressions such as
    * `bob.keyword.do()`. The mode compiler automatically wires this up as a
    * special _internal_ 'on:begin' callback for modes with `beginKeywords`
    * @param {RegExpMatchArray} match
    * @param {CallbackResponse} response
    */
-  function skipIfhasPrecedingOrTrailingDot(match, response) {
+  function skipIfhasPrecedingDot(match, response) {
     const before = match.input[match.index - 1];
-    const after = match.input[match.index + match[0].length];
-    if (before === "." || after === ".") {
+    if (before === ".") {
       response.ignoreMatch();
     }
   }
@@ -331,8 +330,8 @@ export function compileLanguage(language) {
         // or whitespace - this does no harm in any case since our keyword engine
         // doesn't allow spaces in keywords anyways and we still check for the boundary
         // first
-        mode.begin = '\\b(' + mode.beginKeywords.split(' ').join('|') + ')(?=\\b|\\s)';
-        mode.__beforeBegin = skipIfhasPrecedingOrTrailingDot;
+        mode.begin = '\\b(' + mode.beginKeywords.split(' ').join('|') + ')(?!\\.)(?=\\b|\\s)';
+        mode.__beforeBegin = skipIfhasPrecedingDot;
       }
       if (!mode.begin) mode.begin = /\B|\b/;
       cmode.beginRe = langRe(mode.begin);

test/api/index.js

@@ -1,16 +1,17 @@
 'use strict';
 
 describe('hljs', function() {
-  require('./ident');
-  require('./underscoreIdent');
-  require('./number');
-  require('./cNumber');
+  require('./autoDetection');
+  require('./beginKeywords');
   require('./binaryNumber');
-  require('./starters');
+  require('./cNumber');
+  require('./fixmarkup');
   require('./getLanguage');
-  require('./autoDetection');
   require('./highlight');
-  require('./fixmarkup');
+  require('./ident');
   require('./keywords');
+  require('./number');
   require('./registerAlias');
+  require('./starters');
+  require('./underscoreIdent');
 });