fix

book/node_modules/highlight.js/lib/languages/ebnf.js

@@ -0,0 +1,54 @@
+/*
+Language: Extended Backus-Naur Form
+Author: Alex McKibben <alex@nullscope.net>
+Website: https://en.wikipedia.org/wiki/Extended_Backus–Naur_form
+Category: syntax
+*/
+
+/** @type LanguageFn */
+function ebnf(hljs) {
+  const commentMode = hljs.COMMENT(/\(\*/, /\*\)/);
+
+  const nonTerminalMode = {
+    className: "attribute",
+    begin: /^[ ]*[a-zA-Z]+([\s_-]+[a-zA-Z]+)*/
+  };
+
+  const specialSequenceMode = {
+    className: "meta",
+    begin: /\?.*\?/
+  };
+
+  const ruleBodyMode = {
+    begin: /=/,
+    end: /[.;]/,
+    contains: [
+      commentMode,
+      specialSequenceMode,
+      {
+        // terminals
+        className: 'string',
+        variants: [
+          hljs.APOS_STRING_MODE,
+          hljs.QUOTE_STRING_MODE,
+          {
+            begin: '`',
+            end: '`'
+          }
+        ]
+      }
+    ]
+  };
+
+  return {
+    name: 'Extended Backus-Naur Form',
+    illegal: /\S/,
+    contains: [
+      commentMode,
+      nonTerminalMode,
+      ruleBodyMode
+    ]
+  };
+}
+
+module.exports = ebnf;