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Closure Compiler is a JavaScript optimizing compiler. It parses your JavaScript, analyzes it, removes dead code and rewrites and minimizes what's left. It also checks syntax, variable references, and types, and warns about common JavaScript pitfalls. It is used in many of Google's JavaScript apps, including Gmail, Google Web Search, Google Maps, and Google Docs.

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/*
 *
 * ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Rhino code, released
 * May 6, 1999.
 *
 * The Initial Developer of the Original Code is
 * Netscape Communications Corporation.
 * Portions created by the Initial Developer are Copyright (C) 1997-1999
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Roger Lawrence
 *   Mike McCabe
 *   Igor Bukanov
 *   Ethan Hugg
 *   Bob Jervis
 *   Terry Lucas
 *   Milen Nankov
 *   Pascal-Louis Perez
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License Version 2 or later (the "GPL"), in which
 * case the provisions of the GPL are applicable instead of those above. If
 * you wish to allow use of your version of this file only under the terms of
 * the GPL and not to allow others to use your version of this file under the
 * MPL, indicate your decision by deleting the provisions above and replacing
 * them with the notice and other provisions required by the GPL. If you do
 * not delete the provisions above, a recipient may use your version of this
 * file under either the MPL or the GPL.
 *
 * ***** END LICENSE BLOCK ***** */

package com.google.javascript.rhino;

/**
 * This class implements the JavaScript scanner.
 *
 * 

It is based on the C source files jsscan.c and jsscan.h in the jsref package. * *

IMPORTANT: As of 2018-03-09 it is still not possible to use Java 8 features in this file due * to limitations on some internal Google projects that depend on it. */ public final class TokenStream { /** * Is the string an ES3 keyword? * *

Keywords for versions of JavaScript after ES3 are not included, because the parser would * reject valid ES3 code that happened to newer keywords if we did that. * *

Since isKeyword() is used repeatedly in scanning, for performance reasons, it is implemented * to do the minimum number of character comparisons to ascertain whether the given name is a * keyword, instead of doing string search of the name against JS keywords. */ public static boolean isKeyword(String name) { boolean id = false; String s = name; complete: { String X = null; int c; partial: switch (s.length()) { case 2: c=s.charAt(1); if (c=='f') { if (s.charAt(0)=='i') {id=true; break complete;} } else if (c=='n') { if (s.charAt(0)=='i') {id=true; break complete;} } else if (c=='o') { if (s.charAt(0)=='d') {id=true; break complete;} } break partial; case 3: switch (s.charAt(0)) { case 'f': if (s.charAt(2)=='r' && s.charAt(1)=='o') { id=true; break complete; } break partial; case 'i': if (s.charAt(2)=='t' && s.charAt(1)=='n') { id=true; break complete; } break partial; case 'n': if (s.charAt(2)=='w' && s.charAt(1)=='e') { id=true; break complete; } break partial; case 't': if (s.charAt(2)=='y' && s.charAt(1)=='r') { id=true; break complete; } break partial; case 'v': if (s.charAt(2)=='r' && s.charAt(1)=='a') { id=true; break complete; } break partial; } break partial; case 4: switch (s.charAt(0)) { case 'b': X="byte";id=true; break partial; case 'c': c=s.charAt(3); if (c=='e') { if (s.charAt(2)=='s' && s.charAt(1)=='a') { id=true; break complete;} } else if (c=='r') { if (s.charAt(2)=='a' && s.charAt(1)=='h') { id=true; break complete; } } break partial; case 'e': c=s.charAt(3); if (c=='e') { if (s.charAt(2)=='s' && s.charAt(1)=='l') { id=true; break complete;} } else if (c=='m') { if (s.charAt(2)=='u' && s.charAt(1)=='n') { id=true; break complete;} } break partial; case 'g': X="goto";id=true; break partial; case 'l': X="long";id=true; break partial; case 'n': X="null";id=true; break partial; case 't': c=s.charAt(3); if (c=='e') { if (s.charAt(2)=='u' && s.charAt(1)=='r') { id=true; break complete;} } else if (c=='s') { if (s.charAt(2)=='i' && s.charAt(1)=='h') { id=true; break complete;} } break partial; case 'v': X="void";id=true; break partial; case 'w': X="with";id=true; break partial; } break partial; case 5: switch (s.charAt(2)) { case 'a': X="class";id=true; break partial; case 'e': X="break";id=true; break partial; case 'i': X="while";id=true; break partial; case 'l': X="false";id=true; break partial; case 'n': c=s.charAt(0); if (c=='c') { X="const";id=true; } else if (c=='f') { X="final";id=true; } break partial; case 'o': c=s.charAt(0); if (c=='f') { X="float";id=true; } else if (c=='s') { X="short";id=true; } break partial; case 'p': X="super";id=true; break partial; case 'r': X="throw";id=true; break partial; case 't': X="catch";id=true; break partial; } break partial; case 6: switch (s.charAt(1)) { case 'a': X="native";id=true; break partial; case 'e': c=s.charAt(0); if (c=='d') { X="delete";id=true; } else if (c=='r') { X="return";id=true; } break partial; case 'h': X="throws";id=true; break partial; case 'm': X="import";id=true; break partial; case 'o': X="double";id=true; break partial; case 't': X="static";id=true; break partial; case 'u': X="public";id=true; break partial; case 'w': X="switch";id=true; break partial; case 'x': X="export";id=true; break partial; case 'y': X="typeof";id=true; break partial; } break partial; case 7: switch (s.charAt(1)) { case 'a': X="package";id=true; break partial; case 'e': X="default";id=true; break partial; case 'i': X="finally";id=true; break partial; case 'o': X="boolean";id=true; break partial; case 'r': X="private";id=true; break partial; case 'x': X="extends";id=true; break partial; } break partial; case 8: switch (s.charAt(0)) { case 'a': X="abstract";id=true; break partial; case 'c': X="continue";id=true; break partial; case 'd': X="debugger";id=true; break partial; case 'f': X="function";id=true; break partial; case 'v': X="volatile";id=true; break partial; } break partial; case 9: c=s.charAt(0); if (c=='i') { X="interface";id=true; } else if (c=='p') { X="protected";id=true; } else if (c=='t') { X="transient";id=true; } break partial; case 10: c=s.charAt(1); if (c=='m') { X="implements";id=true; } else if (c=='n') { X="instanceof";id=true; } break partial; case 12: X="synchronized";id=true; break partial; } // partial match validate the entire string the one possibility if (X != null && X != s && !X.equals(s)) { return false; } } return id; } public static boolean isJSIdentifier(String s) { return JSIdentifier.isJSIdentifier(s); } private TokenStream() {} }





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