token.java

這是一個javascript 的 interpreter是了解 web browser的好材料

/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 *
 * ***** 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
 *   Bob Jervis
 *   Milen Nankov
 *
 * 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 org.mozilla.javascript;

/**
 * This class implements the JavaScript scanner.
 *
 * It is based on the C source files jsscan.c and jsscan.h
 * in the jsref package.
 *
 * @see org.mozilla.javascript.Parser
 *
 * @author Mike McCabe
 * @author Brendan Eich
 */

public class Token
{

    // debug flags
    public static final boolean printTrees = false;
    static final boolean printICode = false;
    static final boolean printNames = printTrees || printICode;

    /**
     * Token types.  These values correspond to JSTokenType values in
     * jsscan.c.
     */

    public final static int
    // start enum
        ERROR          = -1, // well-known as the only code < EOF
        EOF            = 0,  // end of file token - (not EOF_CHAR)
        EOL            = 1,  // end of line

        // Interpreter reuses the following as bytecodes
        FIRST_BYTECODE_TOKEN    = 2,

        ENTERWITH      = 2,
        LEAVEWITH      = 3,
        RETURN         = 4,
        GOTO           = 5,
        IFEQ           = 6,
        IFNE           = 7,
        SETNAME        = 8,
        BITOR          = 9,
        BITXOR         = 10,
        BITAND         = 11,
        EQ             = 12,
        NE             = 13,
        LT             = 14,
        LE             = 15,
        GT             = 16,
        GE             = 17,
        LSH            = 18,
        RSH            = 19,
        URSH           = 20,
        ADD            = 21,
        SUB            = 22,
        MUL            = 23,
        DIV            = 24,
        MOD            = 25,
        NOT            = 26,
        BITNOT         = 27,
        POS            = 28,
        NEG            = 29,
        NEW            = 30,
        DELPROP        = 31,
        TYPEOF         = 32,
        GETPROP        = 33,
        GETPROPNOWARN  = 34,
        SETPROP        = 35,
        GETELEM        = 36,
        SETELEM        = 37,
        CALL           = 38,
        NAME           = 39,
        NUMBER         = 40,
        STRING         = 41,
        NULL           = 42,
        THIS           = 43,
        FALSE          = 44,
        TRUE           = 45,
        SHEQ           = 46,   // shallow equality (===)
        SHNE           = 47,   // shallow inequality (!==)
        REGEXP         = 48,
        BINDNAME       = 49,
        THROW          = 50,
        RETHROW        = 51, // rethrow caught exception: catch (e if ) use it
        IN             = 52,
        INSTANCEOF     = 53,
        LOCAL_LOAD     = 54,
        GETVAR         = 55,
        SETVAR         = 56,
        CATCH_SCOPE    = 57,
        ENUM_INIT_KEYS = 58,
        ENUM_INIT_VALUES = 59,
        ENUM_INIT_ARRAY= 60,
        ENUM_NEXT      = 61,
        ENUM_ID        = 62,
        THISFN         = 63,
        RETURN_RESULT  = 64, // to return previously stored return result
        ARRAYLIT       = 65, // array literal
        OBJECTLIT      = 66, // object literal
        GET_REF        = 67, // *reference
        SET_REF        = 68, // *reference    = something
        DEL_REF        = 69, // delete reference
        REF_CALL       = 70, // f(args)    = something or f(args)++
        REF_SPECIAL    = 71, // reference for special properties like __proto
        YIELD          = 72,  // JS 1.7 yield pseudo keyword

        // For XML support:
        DEFAULTNAMESPACE = 73, // default xml namespace =
        ESCXMLATTR     = 74,
        ESCXMLTEXT     = 75,
        REF_MEMBER     = 76, // Reference for x.@y, x..y etc.
        REF_NS_MEMBER  = 77, // Reference for x.ns::y, x..ns::y etc.
        REF_NAME       = 78, // Reference for @y, @[y] etc.
        REF_NS_NAME    = 79; // Reference for ns::y, @ns::y@[y] etc.

        // End of interpreter bytecodes
    public final static int
        LAST_BYTECODE_TOKEN    = REF_NS_NAME,

        TRY            = 80,
        SEMI           = 81,  // semicolon
        LB             = 82,  // left and right brackets
        RB             = 83,
        LC             = 84,  // left and right curlies (braces)
        RC             = 85,
        LP             = 86,  // left and right parentheses
        RP             = 87,
        COMMA          = 88,  // comma operator

        ASSIGN         = 89,  // simple assignment  (=)
        ASSIGN_BITOR   = 90,  // |=
        ASSIGN_BITXOR  = 91,  // ^=
        ASSIGN_BITAND  = 92,  // |=
        ASSIGN_LSH     = 93,  // <<=
        ASSIGN_RSH     = 94,  // >>=
        ASSIGN_URSH    = 95,  // >>>=
        ASSIGN_ADD     = 96,  // +=
        ASSIGN_SUB     = 97,  // -=
        ASSIGN_MUL     = 98,  // *=
        ASSIGN_DIV     = 99,  // /=
        ASSIGN_MOD     = 100;  // %=

    public final static int
        FIRST_ASSIGN   = ASSIGN,
        LAST_ASSIGN    = ASSIGN_MOD,

        HOOK           = 101, // conditional (?:)
        COLON          = 102,
        OR             = 103, // logical or (||)
        AND            = 104, // logical and (&&)
        INC            = 105, // increment/decrement (++ --)
        DEC            = 106,
        DOT            = 107, // member operator (.)
        FUNCTION       = 108, // function keyword
        EXPORT         = 109, // export keyword
        IMPORT         = 110, // import keyword
        IF             = 111, // if keyword
        ELSE           = 112, // else keyword
        SWITCH         = 113, // switch keyword
        CASE           = 114, // case keyword
        DEFAULT        = 115, // default keyword
        WHILE          = 116, // while keyword
        DO             = 117, // do keyword
        FOR            = 118, // for keyword
        BREAK          = 119, // break keyword
        CONTINUE       = 120, // continue keyword
        VAR            = 121, // var keyword
        WITH           = 122, // with keyword
        CATCH          = 123, // catch keyword
        FINALLY        = 124, // finally keyword
        VOID           = 125, // void keyword
        RESERVED       = 126, // reserved keywords

        EMPTY          = 127,