phacil-framework/system/ecompress/Helpers/JSMinPlus/JSParser.php

<?php
/**
 * Copyright © 2024 ExacTI Technology Solutions. All rights reserved.
 * GPLv3 General License.
 * https://exacti.com.br
 * Phacil PHP Framework - https://github.com/exacti/phacil-framework
 */

namespace Phacil\Framework\ECompress\Helpers\JSMinPlus;

use Phacil\Framework\Exception;
use Phacil\Framework\ECompress\Helpers\JSMinPlus\JSCompilerContext;
use Phacil\Framework\ECompress\Helpers\JSMinPlus\JSNode;
use Phacil\Framework\ECompress\Helpers\JSMinPlus\JSTokenizer;

/**
 * JSMinPlus version 1.4
 *
 * Minifies a javascript file using a javascript parser
 *
 * This implements a PHP port of Brendan Eich's Narcissus open source javascript engine (in javascript)
 * References: http://en.wikipedia.org/wiki/Narcissus_(JavaScript_engine)
 * Narcissus sourcecode: http://mxr.mozilla.org/mozilla/source/js/narcissus/
 * JSMinPlus weblog: http://crisp.tweakblogs.net/blog/cat/716
 *
 * Tino Zijdel <crisp@tweakers.net>
 *
 * Usage: $minified = JSMinPlus::minify($script [, $filename])
 *
 * Versionlog (see also changelog.txt):
 * 23-07-2011 - remove dynamic creation of OP_* and KEYWORD_* defines and declare them on top
 *              reduce memory footprint by minifying by block-scope
 *              some small byte-saving and performance improvements
 * 12-05-2009 - fixed hook:colon precedence, fixed empty body in loop and if-constructs
 * 18-04-2009 - fixed crashbug in PHP 5.2.9 and several other bugfixes
 * 12-04-2009 - some small bugfixes and performance improvements
 * 09-04-2009 - initial open sourced version 1.0
 *
 * Latest version of this script: http://files.tweakers.net/jsminplus/jsminplus.zip
 *
 */

/* ***** 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): Tino Zijdel <crisp@tweakers.net>
 * PHP port, modifications and minifier routine are (C) 2009-2011
 *
 * 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 ***** */

class JSParser {
	/**
	 * 
	 * @var \Phacil\Framework\ECompress\Helpers\JSMinPlus\JSTokenizer
	 */
	private $t;
	
	private $minifier;

	private $opPrecedence = array(
		';' => 0,
		',' => 1,
		'=' => 2, '?' => 2, ':' => 2,
		// The above all have to have the same precedence, see bug 330975
		'||' => 4,
		'&&' => 5,
		'|' => 6,
		'^' => 7,
		'&' => 8,
		'==' => 9, '!=' => 9, '===' => 9, '!==' => 9,
		'<' => 10, '<=' => 10, '>=' => 10, '>' => 10, 'in' => 10, 'instanceof' => 10,
		'<<' => 11, '>>' => 11, '>>>' => 11,
		'+' => 12, '-' => 12,
		'*' => 13, '/' => 13, '%' => 13,
		'delete' => 14, 'void' => 14, 'typeof' => 14,
		'!' => 14, '~' => 14, 'U+' => 14, 'U-' => 14,
		'++' => 15, '--' => 15,
		'new' => 16,
		'.' => 17,
		JS_NEW_WITH_ARGS => 0, JS_INDEX => 0, JS_CALL => 0,
		JS_ARRAY_INIT => 0, JS_OBJECT_INIT => 0, JS_GROUP => 0
	);

	private $opArity = array(
		',' => -2,
		'=' => 2,
		'?' => 3,
		'||' => 2,
		'&&' => 2,
		'|' => 2,
		'^' => 2,
		'&' => 2,
		'==' => 2, '!=' => 2, '===' => 2, '!==' => 2,
		'<' => 2, '<=' => 2, '>=' => 2, '>' => 2, 'in' => 2, 'instanceof' => 2,
		'<<' => 2, '>>' => 2, '>>>' => 2,
		'+' => 2, '-' => 2,
		'*' => 2, '/' => 2, '%' => 2,
		'delete' => 1, 'void' => 1, 'typeof' => 1,
		'!' => 1, '~' => 1, 'U+' => 1, 'U-' => 1,
		'++' => 1, '--' => 1,
		'new' => 1,
		'.' => 2,
		JS_NEW_WITH_ARGS => 2, JS_INDEX => 2, JS_CALL => 2,
		JS_ARRAY_INIT => 1, JS_OBJECT_INIT => 1, JS_GROUP => 1,
		TOKEN_CONDCOMMENT_START => 1, TOKEN_CONDCOMMENT_END => 1
	);

	public function __construct($minifier=null)
	{
		$this->minifier = $minifier;
		$this->t = new JSTokenizer();
	}

	public function parse($s, $f, $l)
	{
		// initialize tokenizer
		$this->t->init($s, $f, $l);

		$x = new JSCompilerContext(false);
		$n = $this->Script($x);
		if (!$this->t->isDone())
			throw $this->t->newSyntaxError('Syntax error');

		return $n;
	}

	private function Script($x)
	{
		$n = $this->Statements($x);
		$n->type = JS_SCRIPT;
		$n->funDecls = $x->funDecls;
		$n->varDecls = $x->varDecls;

		// minify by scope
		if ($this->minifier)
		{
			$n->value = $this->minifier->parseTree($n);

			// clear tree from node to save memory
			$n->treeNodes = null;
			$n->funDecls = null;
			$n->varDecls = null;

			$n->type = JS_MINIFIED;
		}

		return $n;
	}

	private function Statements($x)
	{
		$n = new JSNode($this->t, JS_BLOCK);
		array_push($x->stmtStack, $n);

		while (!$this->t->isDone() && $this->t->peek() != OP_RIGHT_CURLY)
			$n->addNode($this->Statement($x));

		array_pop($x->stmtStack);

		return $n;
	}

	private function Block($x)
	{
		$this->t->mustMatch(OP_LEFT_CURLY);
		$n = $this->Statements($x);
		$this->t->mustMatch(OP_RIGHT_CURLY);

		return $n;
	}

	private function Statement($x)
	{
		$tt = $this->t->get();
		$n2 = null;

		// Cases for statements ending in a right curly return early, avoiding the
		// common semicolon insertion magic after this switch.
		switch ($tt)
		{
			case KEYWORD_FUNCTION:
				return $this->FunctionDefinition(
					$x,
					true,
					count($x->stmtStack) > 1 ? STATEMENT_FORM : DECLARED_FORM
				);
			break;

			case OP_LEFT_CURLY:
				$n = $this->Statements($x);
				$this->t->mustMatch(OP_RIGHT_CURLY);
			return $n;

			case KEYWORD_IF:
				$n = new JSNode($this->t);
				$n->condition = $this->ParenExpression($x);
				array_push($x->stmtStack, $n);
				$n->thenPart = $this->Statement($x);
				$n->elsePart = $this->t->match(KEYWORD_ELSE) ? $this->Statement($x) : null;
				array_pop($x->stmtStack);
			return $n;

			case KEYWORD_SWITCH:
				$n = new JSNode($this->t);
				$this->t->mustMatch(OP_LEFT_PAREN);
				$n->discriminant = $this->Expression($x);
				$this->t->mustMatch(OP_RIGHT_PAREN);
				$n->cases = array();
				$n->defaultIndex = -1;

				array_push($x->stmtStack, $n);

				$this->t->mustMatch(OP_LEFT_CURLY);

				while (($tt = $this->t->get()) != OP_RIGHT_CURLY)
				{
					switch ($tt)
					{
						case KEYWORD_DEFAULT:
							if ($n->defaultIndex >= 0)
								throw $this->t->newSyntaxError('More than one switch default');
							// FALL THROUGH
						case KEYWORD_CASE:
							$n2 = new JSNode($this->t);
							if ($tt == KEYWORD_DEFAULT)
								$n->defaultIndex = count($n->cases);
							else
								$n2->caseLabel = $this->Expression($x, OP_COLON);
								break;
						default:
							throw $this->t->newSyntaxError('Invalid switch case');
					}

					$this->t->mustMatch(OP_COLON);
					$n2->statements = new JSNode($this->t, JS_BLOCK);
					while (($tt = $this->t->peek()) != KEYWORD_CASE && $tt != KEYWORD_DEFAULT && $tt != OP_RIGHT_CURLY)
						$n2->statements->addNode($this->Statement($x));

					array_push($n->cases, $n2);
				}

				array_pop($x->stmtStack);
			return $n;

			case KEYWORD_FOR:
				$n = new JSNode($this->t);
				$n->isLoop = true;
				$this->t->mustMatch(OP_LEFT_PAREN);

				if (($tt = $this->t->peek()) != OP_SEMICOLON)
				{
					$x->inForLoopInit = true;
					if ($tt == KEYWORD_VAR || $tt == KEYWORD_CONST)
					{
						$this->t->get();
						$n2 = $this->Variables($x);
					}
					else
					{
						$n2 = $this->Expression($x);
					}
					$x->inForLoopInit = false;
				}

				if ($n2 && $this->t->match(KEYWORD_IN))
				{
					$n->type = JS_FOR_IN;
					if ($n2->type == KEYWORD_VAR)
					{
						if (count($n2->treeNodes) != 1)
						{
							throw $this->t->newSyntaxError(
								'Invalid for..in left-hand side',
								$this->t->filename,
								$n2->lineno
							);
						}

						// NB: n2[0].type == IDENTIFIER and n2[0].value == n2[0].name.
						$n->iterator = $n2->treeNodes[0];
						$n->varDecl = $n2;
					}
					else
					{
						$n->iterator = $n2;
						$n->varDecl = null;
					}

					$n->object = $this->Expression($x);
				}
				else
				{
					$n->setup = $n2 ? $n2 : null;
					$this->t->mustMatch(OP_SEMICOLON);
					$n->condition = $this->t->peek() == OP_SEMICOLON ? null : $this->Expression($x);
					$this->t->mustMatch(OP_SEMICOLON);
					$n->update = $this->t->peek() == OP_RIGHT_PAREN ? null : $this->Expression($x);
				}

				$this->t->mustMatch(OP_RIGHT_PAREN);
				$n->body = $this->nest($x, $n);
			return $n;

			case KEYWORD_WHILE:
			        $n = new JSNode($this->t);
			        $n->isLoop = true;
			        $n->condition = $this->ParenExpression($x);
			        $n->body = $this->nest($x, $n);
			return $n;

			case KEYWORD_DO:
				$n = new JSNode($this->t);
				$n->isLoop = true;
				$n->body = $this->nest($x, $n, KEYWORD_WHILE);
				$n->condition = $this->ParenExpression($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.
					$this->t->match(OP_SEMICOLON);
					return $n;
				}
			break;

			case KEYWORD_BREAK:
			case KEYWORD_CONTINUE:
				$n = new JSNode($this->t);

				if ($this->t->peekOnSameLine() == TOKEN_IDENTIFIER)
				{
					$this->t->get();
					$n->label = $this->t->currentToken()->value;
				}

				$ss = $x->stmtStack;
				$i = count($ss);
				$label = $n->label;
				if ($label)
				{
					do
					{
						if (--$i < 0)
							throw $this->t->newSyntaxError('Label not found');
					}
					while ($ss[$i]->label != $label);
				}
				else
				{
					do
					{
						if (--$i < 0)
							throw $this->t->newSyntaxError('Invalid ' . $tt);
					}
					while (!$ss[$i]->isLoop && ($tt != KEYWORD_BREAK || $ss[$i]->type != KEYWORD_SWITCH));
				}

				$n->target = $ss[$i];
			break;

			case KEYWORD_TRY:
				$n = new JSNode($this->t);
				$n->tryBlock = $this->Block($x);
				$n->catchClauses = array();

				while ($this->t->match(KEYWORD_CATCH))
				{
					$n2 = new JSNode($this->t);
					$this->t->mustMatch(OP_LEFT_PAREN);
					$n2->varName = $this->t->mustMatch(TOKEN_IDENTIFIER)->value;

					if ($this->t->match(KEYWORD_IF))
					{
						if ($x->ecmaStrictMode)
							throw $this->t->newSyntaxError('Illegal catch guard');

						if (count($n->catchClauses) && !end($n->catchClauses)->guard)
							throw $this->t->newSyntaxError('Guarded catch after unguarded');

						$n2->guard = $this->Expression($x);
					}
					else
					{
						$n2->guard = null;
					}

					$this->t->mustMatch(OP_RIGHT_PAREN);
					$n2->block = $this->Block($x);
					array_push($n->catchClauses, $n2);
				}

				if ($this->t->match(KEYWORD_FINALLY))
					$n->finallyBlock = $this->Block($x);

				if (!count($n->catchClauses) && !$n->finallyBlock)
					throw $this->t->newSyntaxError('Invalid try statement');
			return $n;

			case KEYWORD_CATCH:
			case KEYWORD_FINALLY:
				throw $this->t->newSyntaxError($tt + ' without preceding try');

			case KEYWORD_THROW:
				$n = new JSNode($this->t);
				$n->value = $this->Expression($x);
			break;

			case KEYWORD_RETURN:
				if (!$x->inFunction)
					throw $this->t->newSyntaxError('Invalid return');

				$n = new JSNode($this->t);
				$tt = $this->t->peekOnSameLine();
				if ($tt != TOKEN_END && $tt != TOKEN_NEWLINE && $tt != OP_SEMICOLON && $tt != OP_RIGHT_CURLY)
					$n->value = $this->Expression($x);
				else
					$n->value = null;
			break;

			case KEYWORD_WITH:
				$n = new JSNode($this->t);
				$n->object = $this->ParenExpression($x);
				$n->body = $this->nest($x, $n);
			return $n;

			case KEYWORD_VAR:
			case KEYWORD_CONST:
			        $n = $this->Variables($x);
			break;

			case TOKEN_CONDCOMMENT_START:
			case TOKEN_CONDCOMMENT_END:
				$n = new JSNode($this->t);
			return $n;

			case KEYWORD_DEBUGGER:
				$n = new JSNode($this->t);
			break;

			case TOKEN_NEWLINE:
			case OP_SEMICOLON:
				$n = new JSNode($this->t, OP_SEMICOLON);
				$n->expression = null;
			return $n;

			default:
				if ($tt == TOKEN_IDENTIFIER)
				{
					$this->t->scanOperand = false;
					$tt = $this->t->peek();
					$this->t->scanOperand = true;
					if ($tt == OP_COLON)
					{
						$label = $this->t->currentToken()->value;
						$ss = $x->stmtStack;
						for ($i = count($ss) - 1; $i >= 0; --$i)
						{
							if ($ss[$i]->label == $label)
								throw $this->t->newSyntaxError('Duplicate label');
						}

						$this->t->get();
						$n = new JSNode($this->t, JS_LABEL);
						$n->label = $label;
						$n->statement = $this->nest($x, $n);

						return $n;
					}
				}

				$n = new JSNode($this->t, OP_SEMICOLON);
				$this->t->unget();
				$n->expression = $this->Expression($x);
				$n->end = $n->expression->end;
			break;
		}

		if ($this->t->lineno == $this->t->currentToken()->lineno)
		{
			$tt = $this->t->peekOnSameLine();
			if ($tt != TOKEN_END && $tt != TOKEN_NEWLINE && $tt != OP_SEMICOLON && $tt != OP_RIGHT_CURLY)
				throw $this->t->newSyntaxError('Missing ; before statement');
		}

		$this->t->match(OP_SEMICOLON);

		return $n;
	}

	private function FunctionDefinition($x, $requireName, $functionForm)
	{
		$f = new JSNode($this->t);

		if ($f->type != KEYWORD_FUNCTION)
			$f->type = ($f->value == 'get') ? JS_GETTER : JS_SETTER;

		if ($this->t->match(TOKEN_IDENTIFIER))
			$f->name = $this->t->currentToken()->value;
		elseif ($requireName)
			throw $this->t->newSyntaxError('Missing function identifier');

		$this->t->mustMatch(OP_LEFT_PAREN);
			$f->params = array();

		while (($tt = $this->t->get()) != OP_RIGHT_PAREN)
		{
			if ($tt != TOKEN_IDENTIFIER)
				throw $this->t->newSyntaxError('Missing formal parameter');

			array_push($f->params, $this->t->currentToken()->value);

			if ($this->t->peek() != OP_RIGHT_PAREN)
				$this->t->mustMatch(OP_COMMA);
		}

		$this->t->mustMatch(OP_LEFT_CURLY);

		$x2 = new JSCompilerContext(true);
		$f->body = $this->Script($x2);

		$this->t->mustMatch(OP_RIGHT_CURLY);
		$f->end = $this->t->currentToken()->end;

		$f->functionForm = $functionForm;
		if ($functionForm == DECLARED_FORM)
			array_push($x->funDecls, $f);

		return $f;
	}

	private function Variables($x)
	{
		$n = new JSNode($this->t);

		do
		{
			$this->t->mustMatch(TOKEN_IDENTIFIER);

			$n2 = new JSNode($this->t);
			$n2->name = $n2->value;

			if ($this->t->match(OP_ASSIGN))
			{
				if ($this->t->currentToken()->assignOp)
					throw $this->t->newSyntaxError('Invalid variable initialization');

				$n2->initializer = $this->Expression($x, OP_COMMA);
			}

			$n2->readOnly = $n->type == KEYWORD_CONST;

			$n->addNode($n2);
			array_push($x->varDecls, $n2);
		}
		while ($this->t->match(OP_COMMA));

		return $n;
	}

	private function Expression($x, $stop=false)
	{
		$operators = array();
		$operands = array();
		$n = false;

		$bl = $x->bracketLevel;
		$cl = $x->curlyLevel;
		$pl = $x->parenLevel;
		$hl = $x->hookLevel;

		while (($tt = $this->t->get()) != TOKEN_END)
		{
			if ($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 OP_SEMICOLON:
					// NB: cannot be empty, Statement handled that.
					break 2;

				case OP_HOOK:
					if ($this->t->scanOperand)
						break 2;

					while (	!empty($operators) &&
						$this->opPrecedence[end($operators)->type] > $this->opPrecedence[$tt]
					)
						$this->reduce($operators, $operands);

					array_push($operators, new JSNode($this->t));

					++$x->hookLevel;
					$this->t->scanOperand = true;
					$n = $this->Expression($x);

					if (!$this->t->match(OP_COLON))
						break 2;

					--$x->hookLevel;
					array_push($operands, $n);
				break;

				case OP_COLON:
					if ($x->hookLevel)
						break 2;

					throw $this->t->newSyntaxError('Invalid label');
				break;

				case OP_ASSIGN:
					if ($this->t->scanOperand)
						break 2;

					// Use >, not >=, for right-associative ASSIGN
					while (	!empty($operators) &&
						$this->opPrecedence[end($operators)->type] > $this->opPrecedence[$tt]
					)
						$this->reduce($operators, $operands);

					array_push($operators, new JSNode($this->t));
					end($operands)->assignOp = $this->t->currentToken()->assignOp;
					$this->t->scanOperand = true;
				break;

				case KEYWORD_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 &&
						!$x->parenLevel
					)
						break 2;
				// FALL THROUGH
				case OP_COMMA:
					// A comma operator should not be parsed if we're parsing the then part
					// of a conditional expression unless it's parenthesized somehow.
					if ($tt == OP_COMMA && $x->hookLevel &&
						!$x->bracketLevel && !$x->curlyLevel &&
						!$x->parenLevel
					)
						break 2;
				// Treat comma as left-associative so reduce can fold left-heavy
				// COMMA trees into a single array.
				// FALL THROUGH
				case OP_OR:
				case OP_AND:
				case OP_BITWISE_OR:
				case OP_BITWISE_XOR:
				case OP_BITWISE_AND:
				case OP_EQ: case OP_NE: case OP_STRICT_EQ: case OP_STRICT_NE:
				case OP_LT: case OP_LE: case OP_GE: case OP_GT:
				case KEYWORD_INSTANCEOF:
				case OP_LSH: case OP_RSH: case OP_URSH:
				case OP_PLUS: case OP_MINUS:
				case OP_MUL: case OP_DIV: case OP_MOD:
				case OP_DOT:
					if ($this->t->scanOperand)
						break 2;

					while (	!empty($operators) &&
						$this->opPrecedence[end($operators)->type] >= $this->opPrecedence[$tt]
					)
						$this->reduce($operators, $operands);

					if ($tt == OP_DOT)
					{
						$this->t->mustMatch(TOKEN_IDENTIFIER);
						array_push($operands, new JSNode($this->t, OP_DOT, array_pop($operands), new JSNode($this->t)));
					}
					else
					{
						array_push($operators, new JSNode($this->t));
						$this->t->scanOperand = true;
					}
				break;

				case KEYWORD_DELETE: case KEYWORD_VOID: case KEYWORD_TYPEOF:
				case OP_NOT: case OP_BITWISE_NOT: case OP_UNARY_PLUS: case OP_UNARY_MINUS:
				case KEYWORD_NEW:
					if (!$this->t->scanOperand)
						break 2;

					array_push($operators, new JSNode($this->t));
				break;

				case OP_INCREMENT: case OP_DECREMENT:
					if ($this->t->scanOperand)
					{
						array_push($operators, new JSNode($this->t));  // prefix increment or decrement
					}
					else
					{
						// Don't cross a line boundary for postfix {in,de}crement.
						$t = $this->t->tokens[($this->t->tokenIndex + $this->t->lookahead - 1) & 3];
						if ($t && $t->lineno != $this->t->lineno)
							break 2;

						if (!empty($operators))
						{
							// Use >, not >=, so postfix has higher precedence than prefix.
							while ($this->opPrecedence[end($operators)->type] > $this->opPrecedence[$tt])
								$this->reduce($operators, $operands);
						}

						$n = new JSNode($this->t, $tt, array_pop($operands));
						$n->postfix = true;
						array_push($operands, $n);
					}
				break;

				case KEYWORD_FUNCTION:
					if (!$this->t->scanOperand)
						break 2;

					array_push($operands, $this->FunctionDefinition($x, false, EXPRESSED_FORM));
					$this->t->scanOperand = false;
				break;

				case KEYWORD_NULL: case KEYWORD_THIS: case KEYWORD_TRUE: case KEYWORD_FALSE:
				case TOKEN_IDENTIFIER: case TOKEN_NUMBER: case TOKEN_STRING: case TOKEN_REGEXP:
					if (!$this->t->scanOperand)
						break 2;

					array_push($operands, new JSNode($this->t));
					$this->t->scanOperand = false;
				break;

				case TOKEN_CONDCOMMENT_START:
				case TOKEN_CONDCOMMENT_END:
					if ($this->t->scanOperand)
						array_push($operators, new JSNode($this->t));
					else
						array_push($operands, new JSNode($this->t));
				break;

				case OP_LEFT_BRACKET:
					if ($this->t->scanOperand)
					{
						// Array initialiser.  Parse using recursive descent, as the
						// sub-grammar here is not an operator grammar.
						$n = new JSNode($this->t, JS_ARRAY_INIT);
						while (($tt = $this->t->peek()) != OP_RIGHT_BRACKET)
						{
							if ($tt == OP_COMMA)
							{
								$this->t->get();
								$n->addNode(null);
								continue;
							}

							$n->addNode($this->Expression($x, OP_COMMA));
							if (!$this->t->match(OP_COMMA))
								break;
						}

						$this->t->mustMatch(OP_RIGHT_BRACKET);
						array_push($operands, $n);
						$this->t->scanOperand = false;
					}
					else
					{
						// Property indexing operator.
						array_push($operators, new JSNode($this->t, JS_INDEX));
						$this->t->scanOperand = true;
						++$x->bracketLevel;
					}
				break;

				case OP_RIGHT_BRACKET:
					if ($this->t->scanOperand || $x->bracketLevel == $bl)
						break 2;

					while ($this->reduce($operators, $operands)->type != JS_INDEX)
						continue;

					--$x->bracketLevel;
				break;

				case OP_LEFT_CURLY:
					if (!$this->t->scanOperand)
						break 2;

					// Object initialiser.  As for array initialisers (see above),
					// parse using recursive descent.
					++$x->curlyLevel;
					$n = new JSNode($this->t, JS_OBJECT_INIT);
					while (!$this->t->match(OP_RIGHT_CURLY))
					{
						do
						{
							$tt = $this->t->get();
							$tv = $this->t->currentToken()->value;
							if (($tv == 'get' || $tv == 'set') && $this->t->peek() == TOKEN_IDENTIFIER)
							{
								if ($x->ecmaStrictMode)
									throw $this->t->newSyntaxError('Illegal property accessor');

								$n->addNode($this->FunctionDefinition($x, true, EXPRESSED_FORM));
							}
							else
							{
								switch ($tt)
								{
									case TOKEN_IDENTIFIER:
									case TOKEN_NUMBER:
									case TOKEN_STRING:
										$id = new JSNode($this->t);
									break;

									case OP_RIGHT_CURLY:
										if ($x->ecmaStrictMode)
											throw $this->t->newSyntaxError('Illegal trailing ,');
									break 3;

									default:
										throw $this->t->newSyntaxError('Invalid property name');
								}

								$this->t->mustMatch(OP_COLON);
								$n->addNode(new JSNode($this->t, JS_PROPERTY_INIT, $id, $this->Expression($x, OP_COMMA)));
							}
						}
						while ($this->t->match(OP_COMMA));

						$this->t->mustMatch(OP_RIGHT_CURLY);
						break;
					}

					array_push($operands, $n);
					$this->t->scanOperand = false;
					--$x->curlyLevel;
				break;

				case OP_RIGHT_CURLY:
					if (!$this->t->scanOperand && $x->curlyLevel != $cl)
						throw new Exception('PANIC: right curly botch');
				break 2;

				case OP_LEFT_PAREN:
					if ($this->t->scanOperand)
					{
						array_push($operators, new JSNode($this->t, JS_GROUP));
					}
					else
					{
						while (	!empty($operators) &&
							$this->opPrecedence[end($operators)->type] > $this->opPrecedence[KEYWORD_NEW]
						)
							$this->reduce($operators, $operands);

						// 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+/-.
						$n = end($operators);
						$this->t->scanOperand = true;
						if ($this->t->match(OP_RIGHT_PAREN))
						{
							if ($n && $n->type == KEYWORD_NEW)
							{
								array_pop($operators);
								$n->addNode(array_pop($operands));
							}
							else
							{
								$n = new JSNode($this->t, JS_CALL, array_pop($operands), new JSNode($this->t, JS_LIST));
							}

							array_push($operands, $n);
							$this->t->scanOperand = false;
							break;
						}

						if ($n && $n->type == KEYWORD_NEW)
							$n->type = JS_NEW_WITH_ARGS;
						else
							array_push($operators, new JSNode($this->t, JS_CALL));
					}

					++$x->parenLevel;
				break;

				case OP_RIGHT_PAREN:
					if ($this->t->scanOperand || $x->parenLevel == $pl)
						break 2;

					while (($tt = $this->reduce($operators, $operands)->type) != JS_GROUP &&
						$tt != JS_CALL && $tt != JS_NEW_WITH_ARGS
					)
					{
						continue;
					}

					if ($tt != JS_GROUP)
					{
						$n = end($operands);
						if ($n->treeNodes[1]->type != OP_COMMA)
							$n->treeNodes[1] = new JSNode($this->t, JS_LIST, $n->treeNodes[1]);
						else
							$n->treeNodes[1]->type = JS_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 2;
			}
		}

		if ($x->hookLevel != $hl)
			throw $this->t->newSyntaxError('Missing : in conditional expression');

		if ($x->parenLevel != $pl)
			throw $this->t->newSyntaxError('Missing ) in parenthetical');

		if ($x->bracketLevel != $bl)
			throw $this->t->newSyntaxError('Missing ] in index expression');

		if ($this->t->scanOperand)
			throw $this->t->newSyntaxError('Missing operand');

		// Resume default mode, scanning for operands, not operators.
		$this->t->scanOperand = true;
		$this->t->unget();

		while (count($operators))
			$this->reduce($operators, $operands);

		return array_pop($operands);
	}

	private function ParenExpression($x)
	{
		$this->t->mustMatch(OP_LEFT_PAREN);
		$n = $this->Expression($x);
		$this->t->mustMatch(OP_RIGHT_PAREN);

		return $n;
	}

	// Statement stack and nested statement handler.
	private function nest($x, $node, $end = false)
	{
		array_push($x->stmtStack, $node);
		$n = $this->statement($x);
		array_pop($x->stmtStack);

		if ($end)
			$this->t->mustMatch($end);

		return $n;
	}

	private function reduce(&$operators, &$operands)
	{
		$n = array_pop($operators);
		$op = $n->type;
		$arity = $this->opArity[$op];
		$c = count($operands);
		if ($arity == -2)
		{
			// Flatten left-associative trees
			if ($c >= 2)
			{
				$left = $operands[$c - 2];
				if ($left->type == $op)
				{
					$right = array_pop($operands);
					$left->addNode($right);
					return $left;
				}
			}
			$arity = 2;
		}

		// Always use push to add operands to n, to update start and end
		$a = array_splice($operands, $c - $arity);
		for ($i = 0; $i < $arity; $i++)
			$n->addNode($a[$i]);

		// Include closing bracket or postfix operator in [start,end]
		$te = $this->t->currentToken()->end;
		if ($n->end < $te)
			$n->end = $te;

		array_push($operands, $n);

		return $n;
	}
}