+++ /dev/null
-<?php
-
-/*
- * This file is part of the Symfony package.
- *
- * (c) Fabien Potencier <fabien@symfony.com>
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace Symfony\Component\ExpressionLanguage;
-
-/**
- * Parsers a token stream.
- *
- * This parser implements a "Precedence climbing" algorithm.
- *
- * @see http://www.engr.mun.ca/~theo/Misc/exp_parsing.htm
- * @see http://en.wikipedia.org/wiki/Operator-precedence_parser
- *
- * @author Fabien Potencier <fabien@symfony.com>
- */
-class Parser
-{
- const OPERATOR_LEFT = 1;
- const OPERATOR_RIGHT = 2;
-
- private $stream;
- private $unaryOperators;
- private $binaryOperators;
- private $functions;
- private $names;
-
- public function __construct(array $functions)
- {
- $this->functions = $functions;
-
- $this->unaryOperators = array(
- 'not' => array('precedence' => 50),
- '!' => array('precedence' => 50),
- '-' => array('precedence' => 500),
- '+' => array('precedence' => 500),
- );
- $this->binaryOperators = array(
- 'or' => array('precedence' => 10, 'associativity' => self::OPERATOR_LEFT),
- '||' => array('precedence' => 10, 'associativity' => self::OPERATOR_LEFT),
- 'and' => array('precedence' => 15, 'associativity' => self::OPERATOR_LEFT),
- '&&' => array('precedence' => 15, 'associativity' => self::OPERATOR_LEFT),
- '|' => array('precedence' => 16, 'associativity' => self::OPERATOR_LEFT),
- '^' => array('precedence' => 17, 'associativity' => self::OPERATOR_LEFT),
- '&' => array('precedence' => 18, 'associativity' => self::OPERATOR_LEFT),
- '==' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '===' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '!=' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '!==' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '<' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '>' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '>=' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '<=' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- 'not in' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- 'in' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- 'matches' => array('precedence' => 20, 'associativity' => self::OPERATOR_LEFT),
- '..' => array('precedence' => 25, 'associativity' => self::OPERATOR_LEFT),
- '+' => array('precedence' => 30, 'associativity' => self::OPERATOR_LEFT),
- '-' => array('precedence' => 30, 'associativity' => self::OPERATOR_LEFT),
- '~' => array('precedence' => 40, 'associativity' => self::OPERATOR_LEFT),
- '*' => array('precedence' => 60, 'associativity' => self::OPERATOR_LEFT),
- '/' => array('precedence' => 60, 'associativity' => self::OPERATOR_LEFT),
- '%' => array('precedence' => 60, 'associativity' => self::OPERATOR_LEFT),
- '**' => array('precedence' => 200, 'associativity' => self::OPERATOR_RIGHT),
- );
- }
-
- /**
- * Converts a token stream to a node tree.
- *
- * The valid names is an array where the values
- * are the names that the user can use in an expression.
- *
- * If the variable name in the compiled PHP code must be
- * different, define it as the key.
- *
- * For instance, ['this' => 'container'] means that the
- * variable 'container' can be used in the expression
- * but the compiled code will use 'this'.
- *
- * @param TokenStream $stream A token stream instance
- * @param array $names An array of valid names
- *
- * @return Node\Node A node tree
- *
- * @throws SyntaxError
- */
- public function parse(TokenStream $stream, $names = array())
- {
- $this->stream = $stream;
- $this->names = $names;
-
- $node = $this->parseExpression();
- if (!$stream->isEOF()) {
- throw new SyntaxError(sprintf('Unexpected token "%s" of value "%s"', $stream->current->type, $stream->current->value), $stream->current->cursor, $stream->getExpression());
- }
-
- return $node;
- }
-
- public function parseExpression($precedence = 0)
- {
- $expr = $this->getPrimary();
- $token = $this->stream->current;
- while ($token->test(Token::OPERATOR_TYPE) && isset($this->binaryOperators[$token->value]) && $this->binaryOperators[$token->value]['precedence'] >= $precedence) {
- $op = $this->binaryOperators[$token->value];
- $this->stream->next();
-
- $expr1 = $this->parseExpression(self::OPERATOR_LEFT === $op['associativity'] ? $op['precedence'] + 1 : $op['precedence']);
- $expr = new Node\BinaryNode($token->value, $expr, $expr1);
-
- $token = $this->stream->current;
- }
-
- if (0 === $precedence) {
- return $this->parseConditionalExpression($expr);
- }
-
- return $expr;
- }
-
- protected function getPrimary()
- {
- $token = $this->stream->current;
-
- if ($token->test(Token::OPERATOR_TYPE) && isset($this->unaryOperators[$token->value])) {
- $operator = $this->unaryOperators[$token->value];
- $this->stream->next();
- $expr = $this->parseExpression($operator['precedence']);
-
- return $this->parsePostfixExpression(new Node\UnaryNode($token->value, $expr));
- }
-
- if ($token->test(Token::PUNCTUATION_TYPE, '(')) {
- $this->stream->next();
- $expr = $this->parseExpression();
- $this->stream->expect(Token::PUNCTUATION_TYPE, ')', 'An opened parenthesis is not properly closed');
-
- return $this->parsePostfixExpression($expr);
- }
-
- return $this->parsePrimaryExpression();
- }
-
- protected function parseConditionalExpression($expr)
- {
- while ($this->stream->current->test(Token::PUNCTUATION_TYPE, '?')) {
- $this->stream->next();
- if (!$this->stream->current->test(Token::PUNCTUATION_TYPE, ':')) {
- $expr2 = $this->parseExpression();
- if ($this->stream->current->test(Token::PUNCTUATION_TYPE, ':')) {
- $this->stream->next();
- $expr3 = $this->parseExpression();
- } else {
- $expr3 = new Node\ConstantNode(null);
- }
- } else {
- $this->stream->next();
- $expr2 = $expr;
- $expr3 = $this->parseExpression();
- }
-
- $expr = new Node\ConditionalNode($expr, $expr2, $expr3);
- }
-
- return $expr;
- }
-
- public function parsePrimaryExpression()
- {
- $token = $this->stream->current;
- switch ($token->type) {
- case Token::NAME_TYPE:
- $this->stream->next();
- switch ($token->value) {
- case 'true':
- case 'TRUE':
- return new Node\ConstantNode(true);
-
- case 'false':
- case 'FALSE':
- return new Node\ConstantNode(false);
-
- case 'null':
- case 'NULL':
- return new Node\ConstantNode(null);
-
- default:
- if ('(' === $this->stream->current->value) {
- if (false === isset($this->functions[$token->value])) {
- throw new SyntaxError(sprintf('The function "%s" does not exist', $token->value), $token->cursor, $this->stream->getExpression());
- }
-
- $node = new Node\FunctionNode($token->value, $this->parseArguments());
- } else {
- if (!in_array($token->value, $this->names, true)) {
- throw new SyntaxError(sprintf('Variable "%s" is not valid', $token->value), $token->cursor, $this->stream->getExpression());
- }
-
- // is the name used in the compiled code different
- // from the name used in the expression?
- if (is_int($name = array_search($token->value, $this->names))) {
- $name = $token->value;
- }
-
- $node = new Node\NameNode($name);
- }
- }
- break;
-
- case Token::NUMBER_TYPE:
- case Token::STRING_TYPE:
- $this->stream->next();
-
- return new Node\ConstantNode($token->value);
-
- default:
- if ($token->test(Token::PUNCTUATION_TYPE, '[')) {
- $node = $this->parseArrayExpression();
- } elseif ($token->test(Token::PUNCTUATION_TYPE, '{')) {
- $node = $this->parseHashExpression();
- } else {
- throw new SyntaxError(sprintf('Unexpected token "%s" of value "%s"', $token->type, $token->value), $token->cursor, $this->stream->getExpression());
- }
- }
-
- return $this->parsePostfixExpression($node);
- }
-
- public function parseArrayExpression()
- {
- $this->stream->expect(Token::PUNCTUATION_TYPE, '[', 'An array element was expected');
-
- $node = new Node\ArrayNode();
- $first = true;
- while (!$this->stream->current->test(Token::PUNCTUATION_TYPE, ']')) {
- if (!$first) {
- $this->stream->expect(Token::PUNCTUATION_TYPE, ',', 'An array element must be followed by a comma');
-
- // trailing ,?
- if ($this->stream->current->test(Token::PUNCTUATION_TYPE, ']')) {
- break;
- }
- }
- $first = false;
-
- $node->addElement($this->parseExpression());
- }
- $this->stream->expect(Token::PUNCTUATION_TYPE, ']', 'An opened array is not properly closed');
-
- return $node;
- }
-
- public function parseHashExpression()
- {
- $this->stream->expect(Token::PUNCTUATION_TYPE, '{', 'A hash element was expected');
-
- $node = new Node\ArrayNode();
- $first = true;
- while (!$this->stream->current->test(Token::PUNCTUATION_TYPE, '}')) {
- if (!$first) {
- $this->stream->expect(Token::PUNCTUATION_TYPE, ',', 'A hash value must be followed by a comma');
-
- // trailing ,?
- if ($this->stream->current->test(Token::PUNCTUATION_TYPE, '}')) {
- break;
- }
- }
- $first = false;
-
- // a hash key can be:
- //
- // * a number -- 12
- // * a string -- 'a'
- // * a name, which is equivalent to a string -- a
- // * an expression, which must be enclosed in parentheses -- (1 + 2)
- if ($this->stream->current->test(Token::STRING_TYPE) || $this->stream->current->test(Token::NAME_TYPE) || $this->stream->current->test(Token::NUMBER_TYPE)) {
- $key = new Node\ConstantNode($this->stream->current->value);
- $this->stream->next();
- } elseif ($this->stream->current->test(Token::PUNCTUATION_TYPE, '(')) {
- $key = $this->parseExpression();
- } else {
- $current = $this->stream->current;
-
- throw new SyntaxError(sprintf('A hash key must be a quoted string, a number, a name, or an expression enclosed in parentheses (unexpected token "%s" of value "%s"', $current->type, $current->value), $current->cursor, $this->stream->getExpression());
- }
-
- $this->stream->expect(Token::PUNCTUATION_TYPE, ':', 'A hash key must be followed by a colon (:)');
- $value = $this->parseExpression();
-
- $node->addElement($value, $key);
- }
- $this->stream->expect(Token::PUNCTUATION_TYPE, '}', 'An opened hash is not properly closed');
-
- return $node;
- }
-
- public function parsePostfixExpression($node)
- {
- $token = $this->stream->current;
- while ($token->type == Token::PUNCTUATION_TYPE) {
- if ('.' === $token->value) {
- $this->stream->next();
- $token = $this->stream->current;
- $this->stream->next();
-
- if (
- $token->type !== Token::NAME_TYPE
- &&
- // Operators like "not" and "matches" are valid method or property names,
- //
- // In other words, besides NAME_TYPE, OPERATOR_TYPE could also be parsed as a property or method.
- // This is because operators are processed by the lexer prior to names. So "not" in "foo.not()" or "matches" in "foo.matches" will be recognized as an operator first.
- // But in fact, "not" and "matches" in such expressions shall be parsed as method or property names.
- //
- // And this ONLY works if the operator consists of valid characters for a property or method name.
- //
- // Other types, such as STRING_TYPE and NUMBER_TYPE, can't be parsed as property nor method names.
- //
- // As a result, if $token is NOT an operator OR $token->value is NOT a valid property or method name, an exception shall be thrown.
- ($token->type !== Token::OPERATOR_TYPE || !preg_match('/[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*/A', $token->value))
- ) {
- throw new SyntaxError('Expected name', $token->cursor, $this->stream->getExpression());
- }
-
- $arg = new Node\ConstantNode($token->value);
-
- $arguments = new Node\ArgumentsNode();
- if ($this->stream->current->test(Token::PUNCTUATION_TYPE, '(')) {
- $type = Node\GetAttrNode::METHOD_CALL;
- foreach ($this->parseArguments()->nodes as $n) {
- $arguments->addElement($n);
- }
- } else {
- $type = Node\GetAttrNode::PROPERTY_CALL;
- }
-
- $node = new Node\GetAttrNode($node, $arg, $arguments, $type);
- } elseif ('[' === $token->value) {
- if ($node instanceof Node\GetAttrNode && Node\GetAttrNode::METHOD_CALL === $node->attributes['type'] && \PHP_VERSION_ID < 50400) {
- throw new SyntaxError('Array calls on a method call is only supported on PHP 5.4+', $token->cursor, $this->stream->getExpression());
- }
-
- $this->stream->next();
- $arg = $this->parseExpression();
- $this->stream->expect(Token::PUNCTUATION_TYPE, ']');
-
- $node = new Node\GetAttrNode($node, $arg, new Node\ArgumentsNode(), Node\GetAttrNode::ARRAY_CALL);
- } else {
- break;
- }
-
- $token = $this->stream->current;
- }
-
- return $node;
- }
-
- /**
- * Parses arguments.
- */
- public function parseArguments()
- {
- $args = array();
- $this->stream->expect(Token::PUNCTUATION_TYPE, '(', 'A list of arguments must begin with an opening parenthesis');
- while (!$this->stream->current->test(Token::PUNCTUATION_TYPE, ')')) {
- if (!empty($args)) {
- $this->stream->expect(Token::PUNCTUATION_TYPE, ',', 'Arguments must be separated by a comma');
- }
-
- $args[] = $this->parseExpression();
- }
- $this->stream->expect(Token::PUNCTUATION_TYPE, ')', 'A list of arguments must be closed by a parenthesis');
-
- return new Node\Node($args);
- }
-}
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