Add a script that generates the regular expressions for identifiers

tools/generate-identifier-regex.js

@@ -0,0 +1,51 @@
+// Based on https://gist.github.com/mathiasbynens/6334847 by @mathias
+
+var regenerate = require('regenerate');
+
+// Which Unicode version should be used?
+var version = '7.0.0'; // note: also update `package.json` when this changes
+
+// Shorthand function
+var get = function(what) {
+    return require('unicode-' + version + '/' + what + '/code-points');
+};
+
+// Unicode categories needed to construct the ES5 regex
+var Lu = get('categories/Lu');
+var Ll = get('categories/Ll');
+var Lt = get('categories/Lt');
+var Lm = get('categories/Lm');
+var Lo = get('categories/Lo');
+var Nl = get('categories/Nl');
+var Mn = get('categories/Mn');
+var Mc = get('categories/Mc');
+var Nd = get('categories/Nd');
+var Pc = get('categories/Pc');
+
+var generateES5Regex = function() { // ES 5.1
+    // http://mathiasbynens.be/notes/javascript-identifiers#valid-identifier-names
+    var identifierStart = regenerate('$', '_')
+        .add(Lu, Ll, Lt, Lm, Lo, Nl)
+        .removeRange(0x010000, 0x10FFFF) // remove astral symbols
+        .removeRange(0x0, 0x7F); // remove ASCII symbols (Acorn-specific)
+    var identifierPart = regenerate('\u200C', '\u200D', Mn, Mc, Nd, Pc)
+        .removeRange(0x010000, 0x10FFFF) // remove astral symbols
+        .remove(identifierStart) // (Acorn-specific)
+        .removeRange(0x0, 0x7F); // remove ASCII symbols (Acorn-specific)
+    return {
+        'NonAsciiIdentifierStart': identifierStart.toString(),
+        'NonAsciiIdentifierPart': identifierPart.toString()
+    };
+};
+
+var result = generateES5Regex();
+console.log(
+    '// ECMAScript 5.1/Unicode v%s `nonASCIIidentifierStart`:\n\n%s\n',
+    version,
+    result.NonAsciiIdentifierStart
+);
+console.log(
+    '// ECMAScript 5.1/Unicode v%s `nonASCIIidentifier`:\n\n%s',
+    version,
+    result.NonAsciiIdentifierPart
+);