fix

book/node_modules/highlight.js/es/languages/brainfuck.js

@@ -0,0 +1,54 @@
+/*
+Language: Brainfuck
+Author: Evgeny Stepanischev <imbolk@gmail.com>
+Website: https://esolangs.org/wiki/Brainfuck
+*/
+
+/** @type LanguageFn */
+function brainfuck(hljs) {
+  const LITERAL = {
+    className: 'literal',
+    begin: /[+-]+/,
+    relevance: 0
+  };
+  return {
+    name: 'Brainfuck',
+    aliases: [ 'bf' ],
+    contains: [
+      hljs.COMMENT(
+        /[^\[\]\.,\+\-<> \r\n]/,
+        /[\[\]\.,\+\-<> \r\n]/,
+        {
+          contains: [
+            {
+              match: /[ ]+[^\[\]\.,\+\-<> \r\n]/,
+              relevance: 0
+            }
+          ],
+          returnEnd: true,
+          relevance: 0
+        }
+      ),
+      {
+        className: 'title',
+        begin: '[\\[\\]]',
+        relevance: 0
+      },
+      {
+        className: 'string',
+        begin: '[\\.,]',
+        relevance: 0
+      },
+      {
+        // this mode works as the only relevance counter
+        // it looks ahead to find the start of a run of literals
+        // so only the runs are counted as relevant
+        begin: /(?=\+\+|--)/,
+        contains: [ LITERAL ]
+      },
+      LITERAL
+    ]
+  };
+}
+
+export { brainfuck as default };