Subversion-Projekte lars-tiefland.prado

/* ***** BEGIN LICENSE BLOCK *****

 * Version: MPL 1.1/GPL 2.0/LGPL 2.1

 *

 * 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 the Narcissus JavaScript engine.

 *

 * The Initial Developer of the Original Code is

 * Brendan Eich <brendan@mozilla.org>.

 * Portions created by the Initial Developer are Copyright (C) 2004

 * the Initial Developer. All Rights Reserved.

 *

 * Contributor(s): Richard Hundt <www.plextk.org>

 *

 * Alternatively, the contents of this file may be used under the terms of

 * either the GNU General Public License Version 2 or later (the "GPL"), or

 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),

 * in which case the provisions of the GPL or the LGPL are applicable instead

 * of those above. If you wish to allow use of your version of this file only

 * under the terms of either the GPL or the LGPL, and not to allow others to

 * use your version of this file under the terms of the MPL, indicate your

 * decision by deleting the provisions above and replace them with the notice

 * and other provisions required by the GPL or the LGPL. If you do not delete

 * the provisions above, a recipient may use your version of this file under

 * the terms of any one of the MPL, the GPL or the LGPL.

 *

 * ***** END LICENSE BLOCK ***** */

/*

 * Narcissus - JS implemented in JS.

 *

 * Lexical scanner and parser.

 */

// jrh

//module('JS.Parse');

// Build a regexp that recognizes operators and punctuators (except newline).

var opRegExp =

/^;|^,|^\?|^:|^\|\||^\&\&|^\||^\^|^\&|^===|^==|^=|^!==|^!=|^<<|^<=|^<|^>>>|^>>|^>=|^>|^\+\+|^\-\-|^\+|^\-|^\*|^\/|^%|^!|^~|^\.|^\[|^\]|^\{|^\}|^\(|^\)/;

// A regexp to match floating point literals (but not integer literals).

var fpRegExp = /^\d+\.\d*(?:[eE][-+]?\d+)?|^\d+(?:\.\d*)?[eE][-+]?\d+|^\.\d+(?:[eE][-+]?\d+)?/;

function Tokenizer(s, f, l) {

    this.cursor = 0;

    this.source = String(s);

    this.tokens = [];

    this.tokenIndex = 0;

    this.lookahead = 0;

    this.scanNewlines = false;

    this.scanOperand = true;

    this.filename = f || "";

    this.lineno = l || 1;

}

Tokenizer.prototype = {

    input : function() {

        return this.source.substring(this.cursor);

    },

    done : function() {

        return this.peek() == END;

    },

    token : function() {

        return this.tokens[this.tokenIndex];

    },

    match: function (tt) {

        return this.get() == tt || this.unget();

    },

    mustMatch: function (tt) {

        if (!this.match(tt))

            throw this.newSyntaxError("Missing " + this.tokens[tt].toLowerCase());

        return this.token();

    },

    peek: function () {

        var tt;

        if (this.lookahead) {

            tt = this.tokens[(this.tokenIndex + this.lookahead) & 3].type;

        } else {

            tt = this.get();

            this.unget();

        }

        return tt;

    },

    peekOnSameLine: function () {

        this.scanNewlines = true;

        var tt = this.peek();

        this.scanNewlines = false;

        return tt;

    },

    get: function () {

        var token;

        while (this.lookahead) {

            --this.lookahead;

            this.tokenIndex = (this.tokenIndex + 1) & 3;

            token = this.tokens[this.tokenIndex];

            if (token.type != NEWLINE || this.scanNewlines)

                return token.type;

        }

        for (;;) {

            var input = this.input();

            var rx = this.scanNewlines ? /^[ \t]+/ : /^\s+/;

            var match = input.match(rx);

            if (match) {

                var spaces = match[0];

                this.cursor += spaces.length;

                var newlines = spaces.match(/\n/g);

                if (newlines)

                    this.lineno += newlines.length;

                input = this.input();

            }

            if (!(match = input.match(/^\/(?:\*(?:.|\n)*?\*\/|\/.*)/)))

                break;

            var comment = match[0];

            this.cursor += comment.length;

            newlines = comment.match(/\n/g);

            if (newlines)

                this.lineno += newlines.length

        }

        this.tokenIndex = (this.tokenIndex + 1) & 3;

        token = this.tokens[this.tokenIndex];

        if (!token)

            this.tokens[this.tokenIndex] = token = {};

        if (!input)

            return token.type = END;

        if ((match = input.match(fpRegExp))) {

            token.type = NUMBER;

            token.value = parseFloat(match[0]);

        } else if ((match = input.match(/^0[xX][\da-fA-F]+|^0[0-7]*|^\d+/))) {

            token.type = NUMBER;

            token.value = parseInt(match[0]);

        } else if ((match = input.match(/^((\$\w*)|(\w+))/))) {

            var id = match[0];

            token.type = keywords[id] || IDENTIFIER;

            token.value = id;

        } else if ((match = input.match(/^"(?:\\.|[^"])*"|^'(?:[^']|\\.)*'/))) {

            token.type = STRING;

            token.value = eval(match[0]);

        } else if (this.scanOperand &&

                   (match = input.match(/^\/((?:\\.|[^\/])+)\/([gi]*)/))) {

            token.type = REGEXP;

            token.value = new RegExp(match[1], match[2]);

        } else if ((match = input.match(opRegExp))) {

            var op = match[0];

            if (assignOps[op] && input[op.length] == '=') {

                token.type = ASSIGN;

                token.assignOp = GLOBAL[opTypeNames[op]];

                match[0] += '=';

            } else {

                token.type = GLOBAL[opTypeNames[op]];

                if (this.scanOperand &&

                    (token.type == PLUS || token.type == MINUS)) {

                    token.type += UNARY_PLUS - PLUS;

                }

                token.assignOp = null;

            }

            //debug('token.value => '+op+', token.type => '+token.type);

            token.value = op;

        } else {

            throw this.newSyntaxError("Illegal token");

        }

        token.start = this.cursor;

        this.cursor += match[0].length;

        token.end = this.cursor;

        token.lineno = this.lineno;

        return token.type;

    },

    unget: function () {

        if (++this.lookahead == 4) throw "PANIC: too much lookahead!";

        this.tokenIndex = (this.tokenIndex - 1) & 3;

    },

    newSyntaxError: function (m) {

        var e = new SyntaxError(m, this.filename, this.lineno);

        e.source = this.source;

        e.cursor = this.cursor;

        return e;

    }

};

function CompilerContext(inFunction) {

    this.inFunction = inFunction;

    this.stmtStack = [];

    this.funDecls = [];

    this.varDecls = [];

}

var CCp = CompilerContext.prototype;

CCp.bracketLevel = CCp.curlyLevel = CCp.parenLevel = CCp.hookLevel = 0;

CCp.ecmaStrictMode = CCp.inForLoopInit = false;

function Script(t, x) {

    var n = Statements(t, x);

    n.type = SCRIPT;

    n.funDecls = x.funDecls;

    n.varDecls = x.varDecls;

    return n;

}

// Node extends Array, which we extend slightly with a top-of-stack method.

Array.prototype.top = function() {

    return this.length && this[this.length-1];

}

function NarcNode(t, type) {

    var token = t.token();

    if (token) {

        this.type = type || token.type;

        this.value = token.value;

        this.lineno = token.lineno;

        this.start = token.start;

        this.end = token.end;

    } else {

        this.type = type;

        this.lineno = t.lineno;

    }

    this.tokenizer = t;

    for (var i = 2; i < arguments.length; i++)

        this.push(arguments[i]);

}

var Np = NarcNode.prototype = new Array();

Np.constructor = NarcNode;

Np.$length = 0;

Np.toSource = Object.prototype.toSource;

// Always use push to add operands to an expression, to update start and end.

Np.push = function (kid) {

    if (kid.start < this.start)

        this.start = kid.start;

    if (this.end < kid.end)

        this.end = kid.end;

    //debug('length before => '+this.$length);

    this[this.$length] = kid;

    this.$length++;

    //debug('length after => '+this.$length);

}

NarcNode.indentLevel = 0;

function tokenstr(tt) {

    var t = tokens[tt];

    return /^\W/.test(t) ? opTypeNames[t] : t.toUpperCase();

}

Np.toString = function () {

    var a = [];

    for (var i in this) {

        if (this.hasOwnProperty(i) && i != 'type')

            a.push({id: i, value: this[i]});

    }

    a.sort(function (a,b) { return (a.id < b.id) ? -1 : 1; });

    INDENTATION = "    ";

    var n = ++NarcNode.indentLevel;

    var s = "{\n" + INDENTATION.repeat(n) + "type: " + tokenstr(this.type);

    for (i = 0; i < a.length; i++)

        s += ",\n" + INDENTATION.repeat(n) + a[i].id + ": " + a[i].value;

    n = --NarcNode.indentLevel;

    s += "\n" + INDENTATION.repeat(n) + "}";

    return s;

}

Np.getSource = function () {

    return this.tokenizer.source.slice(this.start, this.end);

};

Np.filename = function () { return this.tokenizer.filename; };

String.prototype.repeat = function (n) {

    var s = "", t = this + s;

    while (--n >= 0)

        s += t;

    return s;

}

// Statement stack and nested statement handler.

function nest(t, x, node, func, end) {

    x.stmtStack.push(node);

    var n = func(t, x);

    x.stmtStack.pop();

    end && t.mustMatch(end);

    return n;

}

function Statements(t, x) {

    var n = new NarcNode(t, BLOCK);

    x.stmtStack.push(n);

    while (!t.done() && t.peek() != RIGHT_CURLY)

        n.push(Statement(t, x));

    x.stmtStack.pop();

    return n;

}

function Block(t, x) {

    t.mustMatch(LEFT_CURLY);

    var n = Statements(t, x);

    t.mustMatch(RIGHT_CURLY);

    return n;

}

DECLARED_FORM = 0; EXPRESSED_FORM = 1; STATEMENT_FORM = 2;

function Statement(t, x) {

    var i, label, n, n2, ss, tt = t.get();

    // Cases for statements ending in a right curly return early, avoiding the

    // common semicolon insertion magic after this switch.

    switch (tt) {

      case FUNCTION:

        return FunctionDefinition(t, x, true,

                                  (x.stmtStack.length > 1)

                                  ? STATEMENT_FORM

                                  : DECLARED_FORM);

      case LEFT_CURLY:

        n = Statements(t, x);

        t.mustMatch(RIGHT_CURLY);

        return n;

      case IF:

        n = new NarcNode(t);

        n.condition = ParenExpression(t, x);

        x.stmtStack.push(n);

        n.thenPart = Statement(t, x);

        n.elsePart = t.match(ELSE) ? Statement(t, x) : null;

        x.stmtStack.pop();

        return n;

      case SWITCH:

        n = new NarcNode(t);

        t.mustMatch(LEFT_PAREN);

        n.discriminant = Expression(t, x);

        t.mustMatch(RIGHT_PAREN);

        n.cases = [];

        n.defaultIndex = -1;

        x.stmtStack.push(n);

        t.mustMatch(LEFT_CURLY);

        while ((tt = t.get()) != RIGHT_CURLY) {

            switch (tt) {

              case DEFAULT:

                if (n.defaultIndex >= 0)

                    throw t.newSyntaxError("More than one switch default");

                // FALL THROUGH

              case CASE:

                n2 = new NarcNode(t);

                if (tt == DEFAULT)

                    n.defaultIndex = n.cases.length;

                else

                    n2.caseLabel = Expression(t, x, COLON);

                break;

              default:

                throw t.newSyntaxError("Invalid switch case");

            }

            t.mustMatch(COLON);

            n2.statements = new NarcNode(t, BLOCK);

            while ((tt=t.peek()) != CASE && tt != DEFAULT && tt != RIGHT_CURLY)

                n2.statements.push(Statement(t, x));

            n.cases.push(n2);

        }

        x.stmtStack.pop();

        return n;

      case FOR:

        n = new NarcNode(t);

        n.isLoop = true;

        t.mustMatch(LEFT_PAREN);

        if ((tt = t.peek()) != SEMICOLON) {

            x.inForLoopInit = true;

            if (tt == VAR || tt == CONST) {

                t.get();

                n2 = Variables(t, x);

            } else {

                n2 = Expression(t, x);

            }

            x.inForLoopInit = false;

        }

        if (n2 && t.match(IN)) {

            n.type = FOR_IN;

            if (n2.type == VAR) {

                if (n2.$length != 1) {

                    throw new SyntaxError("Invalid for..in left-hand side",

                                          t.filename, n2.lineno);

                }

                // NB: n2[0].type == IDENTIFIER and n2[0].value == n2[0].name.

                n.iterator = n2[0];

                n.varDecl = n2;

            } else {

                n.iterator = n2;

                n.varDecl = null;

            }

            n.object = Expression(t, x);

        } else {

            n.setup = n2 || null;

            t.mustMatch(SEMICOLON);

            n.condition = (t.peek() == SEMICOLON) ? null : Expression(t, x);

            t.mustMatch(SEMICOLON);

            n.update = (t.peek() == RIGHT_PAREN) ? null : Expression(t, x);

        }

        t.mustMatch(RIGHT_PAREN);

        n.body = nest(t, x, n, Statement);

        return n;

      case WHILE:

        n = new NarcNode(t);

        n.isLoop = true;

        n.condition = ParenExpression(t, x);

        n.body = nest(t, x, n, Statement);

        return n;

      case DO:

        n = new NarcNode(t);

        n.isLoop = true;

        n.body = nest(t, x, n, Statement, WHILE);

        n.condition = ParenExpression(t, x);

        if (!x.ecmaStrictMode) {

            // <script language="JavaScript"> (without version hints) may need

            // automatic semicolon insertion without a newline after do-while.

            // See http://bugzilla.mozilla.org/show_bug.cgi?id=238945.

            t.match(SEMICOLON);

            return n;

        }

        break;

      case BREAK:

      case CONTINUE:

        n = new NarcNode(t);

        if (t.peekOnSameLine() == IDENTIFIER) {

            t.get();

            n.label = t.token().value;

        }

        ss = x.stmtStack;

        i = ss.length;

        label = n.label;

        if (label) {

            do {

                if (--i < 0)

                    throw t.newSyntaxError("Label not found");

            } while (ss[i].label != label);

        } else {

            do {

                if (--i < 0) {

                    throw t.newSyntaxError("Invalid " + ((tt == BREAK)

                                                         ? "break"

                                                         : "continue"));

                }

            } while (!ss[i].isLoop && (tt != BREAK || ss[i].type != SWITCH));

        }

        n.target = ss[i];

        break;

      case TRY:

        n = new NarcNode(t);

        n.tryBlock = Block(t, x);

        n.catchClauses = [];

        while (t.match(CATCH)) {

            n2 = new NarcNode(t);

            t.mustMatch(LEFT_PAREN);

            n2.varName = t.mustMatch(IDENTIFIER).value;

            if (t.match(IF)) {

                if (x.ecmaStrictMode)

                    throw t.newSyntaxError("Illegal catch guard");

                if (n.catchClauses.length && !n.catchClauses.top().guard)

                    throw t.newSyntaxError("Guarded catch after unguarded");

                n2.guard = Expression(t, x);

            } else {

                n2.guard = null;

            }

            t.mustMatch(RIGHT_PAREN);

            n2.block = Block(t, x);

            n.catchClauses.push(n2);

        }

        if (t.match(FINALLY))

            n.finallyBlock = Block(t, x);

        if (!n.catchClauses.length && !n.finallyBlock)

            throw t.newSyntaxError("Invalid try statement");

        return n;

      case CATCH:

      case FINALLY:

        throw t.newSyntaxError(tokens[tt] + " without preceding try");

      case THROW:

        n = new NarcNode(t);

        n.exception = Expression(t, x);

        break;

      case RETURN:

        if (!x.inFunction)

            throw t.newSyntaxError("Invalid return");

        n = new NarcNode(t);

        tt = t.peekOnSameLine();

        if (tt != END && tt != NEWLINE && tt != SEMICOLON && tt != RIGHT_CURLY)

            n.value = Expression(t, x);

        break;

      case WITH:

        n = new NarcNode(t);

        n.object = ParenExpression(t, x);

        n.body = nest(t, x, n, Statement);

        return n;

      case VAR:

      case CONST:

        n = Variables(t, x);

        break;

      case DEBUGGER:

        n = new NarcNode(t);

        break;

      case REQUIRE:

        n = new NarcNode(t);

        n.classPath = ParenExpression(t, x);

        break;

      case NEWLINE:

      case SEMICOLON:

        n = new NarcNode(t, SEMICOLON);

        n.expression = null;

        return n;

      default:

        if (tt == IDENTIFIER && t.peek() == COLON) {

            label = t.token().value;

            ss = x.stmtStack;

            for (i = ss.length-1; i >= 0; --i) {

                if (ss[i].label == label)

                    throw t.newSyntaxError("Duplicate label");

            }

            t.get();

            n = new NarcNode(t, LABEL);

            n.label = label;

            n.statement = nest(t, x, n, Statement);

            return n;

        }

        n = new NarcNode(t, SEMICOLON);

        t.unget();

        n.expression = Expression(t, x);

        n.end = n.expression.end;

        break;

    }

    if (t.lineno == t.token().lineno) {

        tt = t.peekOnSameLine();

        if (tt != END && tt != NEWLINE && tt != SEMICOLON && tt != RIGHT_CURLY)

            throw t.newSyntaxError("Missing ; before statement");

    }

    t.match(SEMICOLON);

    return n;

}

function FunctionDefinition(t, x, requireName, functionForm) {

    var f = new NarcNode(t);

    if (f.type != FUNCTION)

        f.type = (f.value == "get") ? GETTER : SETTER;

    if (t.match(IDENTIFIER)) {

        f.name = t.token().value;

    }

    else if (requireName)

        throw t.newSyntaxError("Missing function identifier");

    t.mustMatch(LEFT_PAREN);

    f.params = [];

    var tt;

    while ((tt = t.get()) != RIGHT_PAREN) {

        if (tt != IDENTIFIER)

            throw t.newSyntaxError("Missing formal parameter");

        f.params.push(t.token().value);

        if (t.peek() != RIGHT_PAREN)

            t.mustMatch(COMMA);

    }

    t.mustMatch(LEFT_CURLY);

    var x2 = new CompilerContext(true);

    f.body = Script(t, x2);

    t.mustMatch(RIGHT_CURLY);

    f.end = t.token().end;

    f.functionForm = functionForm;

    if (functionForm == DECLARED_FORM) {

        x.funDecls.push(f);

    }

    return f;

}

function Variables(t, x) {

    var n = new NarcNode(t);

    do {

        t.mustMatch(IDENTIFIER);

        var n2 = new NarcNode(t);

        n2.name = n2.value;

        if (t.match(ASSIGN)) {

            if (t.token().assignOp)

                throw t.newSyntaxError("Invalid variable initialization");

            n2.initializer = Expression(t, x, COMMA);

        }

        n2.readOnly = (n.type == CONST);

        n.push(n2);

        x.varDecls.push(n2);

    } while (t.match(COMMA));

    return n;

}

function ParenExpression(t, x) {

    t.mustMatch(LEFT_PAREN);

    var n = Expression(t, x);

    t.mustMatch(RIGHT_PAREN);

    return n;

}

var opPrecedence = {

    SEMICOLON: 0,

    COMMA: 1,

    ASSIGN: 2, HOOK: 2, COLON: 2, CONDITIONAL: 2,

    // The above all have to have the same precedence, see bug 330975.

    OR: 4,

    AND: 5,

    BITWISE_OR: 6,

    BITWISE_XOR: 7,

    BITWISE_AND: 8,

    EQ: 9, NE: 9, STRICT_EQ: 9, STRICT_NE: 9,

    LT: 10, LE: 10, GE: 10, GT: 10, IN: 10, INSTANCEOF: 10,

    LSH: 11, RSH: 11, URSH: 11,

    PLUS: 12, MINUS: 12,

    MUL: 13, DIV: 13, MOD: 13,

    DELETE: 14, VOID: 14, TYPEOF: 14, // PRE_INCREMENT: 14, PRE_DECREMENT: 14,

    NOT: 14, BITWISE_NOT: 14, UNARY_PLUS: 14, UNARY_MINUS: 14,

    INCREMENT: 15, DECREMENT: 15,     // postfix

    NEW: 16,

    DOT: 17

};

// Map operator type code to precedence.

for (i in opPrecedence)

    opPrecedence[GLOBAL[i]] = opPrecedence[i];

var opArity = {

    COMMA: -2,

    ASSIGN: 2,

    CONDITIONAL: 3,

    OR: 2,

    AND: 2,

    BITWISE_OR: 2,

    BITWISE_XOR: 2,

    BITWISE_AND: 2,

    EQ: 2, NE: 2, STRICT_EQ: 2, STRICT_NE: 2,

    LT: 2, LE: 2, GE: 2, GT: 2, IN: 2, INSTANCEOF: 2,

    LSH: 2, RSH: 2, URSH: 2,

    PLUS: 2, MINUS: 2,

    MUL: 2, DIV: 2, MOD: 2,

    DELETE: 1, VOID: 1, TYPEOF: 1,  // PRE_INCREMENT: 1, PRE_DECREMENT: 1,

    NOT: 1, BITWISE_NOT: 1, UNARY_PLUS: 1, UNARY_MINUS: 1,

    INCREMENT: 1, DECREMENT: 1,     // postfix

    NEW: 1, NEW_WITH_ARGS: 2, DOT: 2, INDEX: 2, CALL: 2,

    ARRAY_INIT: 1, OBJECT_INIT: 1, GROUP: 1

};

// Map operator type code to arity.

for (i in opArity)

    opArity[GLOBAL[i]] = opArity[i];

function Expression(t, x, stop) {

    var n, id, tt, operators = [], operands = [];

    var bl = x.bracketLevel, cl = x.curlyLevel, pl = x.parenLevel,

        hl = x.hookLevel;

    function reduce() {

        //debug('OPERATORS => '+operators);

        var n = operators.pop();

        var op = n.type;

        var arity = opArity[op];

        if (arity == -2) {

            // Flatten left-associative trees.

            var left = operands.length >= 2 && operands[operands.length-2];

            if (left.type == op) {

                var right = operands.pop();

                left.push(right);

                return left;

            }

            arity = 2;

        }

        // Always use push to add operands to n, to update start and end.

        var a = operands.splice(operands.length - arity, operands.length);

        for (var i = 0; i < arity; i++) {

            n.push(a[i]);

        }

        // Include closing bracket or postfix operator in [start,end).

        if (n.end < t.token().end)

            n.end = t.token().end;

        operands.push(n);

        return n;

    }

loop:

    while ((tt = t.get()) != END) {

        //debug('TT => '+tokens[tt]);

        if (tt == stop &&

            x.bracketLevel == bl && x.curlyLevel == cl && x.parenLevel == pl &&

            x.hookLevel == hl) {

            // Stop only if tt matches the optional stop parameter, and that

            // token is not quoted by some kind of bracket.

            break;

        }

        switch (tt) {

          case SEMICOLON:

            // NB: cannot be empty, Statement handled that.

            break loop;

          case ASSIGN:

          case HOOK:

          case COLON:

            if (t.scanOperand)

                break loop;

            // Use >, not >=, for right-associative ASSIGN and HOOK/COLON.

            while (operators.length && opPrecedence[operators.top().type] > opPrecedence[tt] ||

                   (tt == COLON && operators.top().type == ASSIGN)) {

                reduce();

            }

            if (tt == COLON) {

                n = operators.top();

                if (n.type != HOOK)

                    throw t.newSyntaxError("Invalid label");

                n.type = CONDITIONAL;

                --x.hookLevel;

            } else {

                operators.push(new NarcNode(t));

                if (tt == ASSIGN)

                    operands.top().assignOp = t.token().assignOp;

                else

                    ++x.hookLevel;      // tt == HOOK

            }

            t.scanOperand = true;

            break;

          case IN:

            // An in operator should not be parsed if we're parsing the head of

            // a for (...) loop, unless it is in the then part of a conditional

            // expression, or parenthesized somehow.

            if (x.inForLoopInit && !x.hookLevel &&

                !x.bracketLevel && !x.curlyLevel && !x.parenLevel) {

                break loop;

            }

            // FALL THROUGH

          case COMMA:

            // Treat comma as left-associative so reduce can fold left-heavy

            // COMMA trees into a single array.

            // FALL THROUGH

          case OR:

          case AND:

          case BITWISE_OR:

          case BITWISE_XOR:

          case BITWISE_AND:

          case EQ: case NE: case STRICT_EQ: case STRICT_NE:

          case LT: case LE: case GE: case GT:

          case INSTANCEOF:

          case LSH: case RSH: case URSH:

          case PLUS: case MINUS:

          case MUL: case DIV: case MOD:

          case DOT:

            if (t.scanOperand)

                break loop;

            while (operators.length && opPrecedence[operators.top().type] >= opPrecedence[tt])

                reduce();

            if (tt == DOT) {

                t.mustMatch(IDENTIFIER);

                operands.push(new NarcNode(t, DOT, operands.pop(), new NarcNode(t)));

            } else {

                operators.push(new NarcNode(t));

                t.scanOperand = true;

            }

            break;

          case DELETE: case VOID: case TYPEOF:

          case NOT: case BITWISE_NOT: case UNARY_PLUS: case UNARY_MINUS:

          case NEW:

            if (!t.scanOperand)

                break loop;

            operators.push(new NarcNode(t));

            break;

          case INCREMENT: case DECREMENT:

            if (t.scanOperand) {

                operators.push(new NarcNode(t));  // prefix increment or decrement

            } else {

                // Use >, not >=, so postfix has higher precedence than prefix.

                while (operators.length && opPrecedence[operators.top().type] > opPrecedence[tt])

                    reduce();

                n = new NarcNode(t, tt, operands.pop());

                n.postfix = true;

                operands.push(n);

            }

            break;

          case FUNCTION:

            if (!t.scanOperand)

                break loop;

            operands.push(FunctionDefinition(t, x, false, EXPRESSED_FORM));

            t.scanOperand = false;

            break;

          case NULL: case THIS: case TRUE: case FALSE:

          case IDENTIFIER: case NUMBER: case STRING: case REGEXP:

            if (!t.scanOperand)

                break loop;

            operands.push(new NarcNode(t));

            t.scanOperand = false;

            break;

          case LEFT_BRACKET:

            if (t.scanOperand) {

                // Array initialiser.  Parse using recursive descent, as the

                // sub-grammar here is not an operator grammar.

                n = new NarcNode(t, ARRAY_INIT);

                while ((tt = t.peek()) != RIGHT_BRACKET) {

                    if (tt == COMMA) {

                        t.get();

                        n.push(null);

                        continue;

                    }

                    n.push(Expression(t, x, COMMA));

                    if (!t.match(COMMA))

                        break;

                }

                t.mustMatch(RIGHT_BRACKET);

                operands.push(n);

                t.scanOperand = false;

            } else {

                // Property indexing operator.

                operators.push(new NarcNode(t, INDEX));

                t.scanOperand = true;

                ++x.bracketLevel;

            }

            break;

          case RIGHT_BRACKET:

            if (t.scanOperand || x.bracketLevel == bl)

                break loop;

            while (reduce().type != INDEX)

                continue;

            --x.bracketLevel;

            break;

          case LEFT_CURLY:

            if (!t.scanOperand)

                break loop;

            // Object initialiser.  As for array initialisers (see above),

            // parse using recursive descent.

            ++x.curlyLevel;

            n = new NarcNode(t, OBJECT_INIT);

          object_init:

            if (!t.match(RIGHT_CURLY)) {

                do {

                    tt = t.get();

                    if ((t.token().value == "get" || t.token().value == "set") &&

                        t.peek() == IDENTIFIER) {

                        if (x.ecmaStrictMode)

                            throw t.newSyntaxError("Illegal property accessor");

                        n.push(FunctionDefinition(t, x, true, EXPRESSED_FORM));

                    } else {

                        switch (tt) {

                          case IDENTIFIER:

                          case NUMBER:

                          case STRING:

                            id = new NarcNode(t);

                            break;

                          case RIGHT_CURLY:

                            if (x.ecmaStrictMode)

                                throw t.newSyntaxError("Illegal trailing ,");

                            break object_init;

                          default:

                            throw t.newSyntaxError("Invalid property name");

                        }

                        t.mustMatch(COLON);

                        n.push(new NarcNode(t, PROPERTY_INIT, id,

                                        Expression(t, x, COMMA)));

                    }

                } while (t.match(COMMA));

                t.mustMatch(RIGHT_CURLY);

            }

            operands.push(n);

            t.scanOperand = false;

            --x.curlyLevel;

            break;

          case RIGHT_CURLY:

            if (!t.scanOperand && x.curlyLevel != cl)

                throw "PANIC: right curly botch";

            break loop;

          case LEFT_PAREN:

            if (t.scanOperand) {

                operators.push(new NarcNode(t, GROUP));

            } else {

                while (operators.length && opPrecedence[operators.top().type] > opPrecedence[NEW])

                    reduce();

                // Handle () now, to regularize the n-ary case for n > 0.

                // We must set scanOperand in case there are arguments and

                // the first one is a regexp or unary+/-.

                n = operators.top();

                t.scanOperand = true;

                if (t.match(RIGHT_PAREN)) {

                    if (n.type == NEW) {

                        --operators.length;

                        n.push(operands.pop());

                    } else {

                        n = new NarcNode(t, CALL, operands.pop(),

                                     new NarcNode(t, LIST));

                    }

                    operands.push(n);

                    t.scanOperand = false;

                    break;

                }

                if (n.type == NEW)

                    n.type = NEW_WITH_ARGS;

                else

                    operators.push(new NarcNode(t, CALL));

            }

            ++x.parenLevel;

            break;

          case RIGHT_PAREN:

            if (t.scanOperand || x.parenLevel == pl)

                break loop;

            while ((tt = reduce().type) != GROUP && tt != CALL &&

                   tt != NEW_WITH_ARGS) {

                continue;

            }

            if (tt != GROUP) {

                n = operands.top();

                if (n[1].type != COMMA)

                    n[1] = new NarcNode(t, LIST, n[1]);

                else

                    n[1].type = LIST;

            }

            --x.parenLevel;

            break;

          // Automatic semicolon insertion means we may scan across a newline

          // and into the beginning of another statement.  If so, break out of

          // the while loop and let the t.scanOperand logic handle errors.

          default:

            break loop;

        }

    }

    if (x.hookLevel != hl)

        throw t.newSyntaxError("Missing : after ?");

    if (x.parenLevel != pl)

        throw t.newSyntaxError("Missing ) in parenthetical");

    if (x.bracketLevel != bl)

        throw t.newSyntaxError("Missing ] in index expression");

    if (t.scanOperand)

        throw t.newSyntaxError("Missing operand");

    // Resume default mode, scanning for operands, not operators.

    t.scanOperand = true;

    t.unget();

    while (operators.length)

        reduce();

    return operands.pop();

}

function parse(s, f, l) {

    var t = new Tokenizer(s, f, l);

    var x = new CompilerContext(false);

    var n = Script(t, x);

    if (!t.done())

        throw t.newSyntaxError("Syntax error");

    return n;

}