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- <?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;
- use Psr\Cache\CacheItemPoolInterface;
- use Symfony\Component\Cache\Adapter\ArrayAdapter;
- // Help opcache.preload discover always-needed symbols
- class_exists(ParsedExpression::class);
- /**
- * Allows to compile and evaluate expressions written in your own DSL.
- *
- * @author Fabien Potencier <fabien@symfony.com>
- */
- class ExpressionLanguage
- {
- private $cache;
- private $lexer;
- private $parser;
- private $compiler;
- protected $functions = [];
- /**
- * @param ExpressionFunctionProviderInterface[] $providers
- */
- public function __construct(CacheItemPoolInterface $cache = null, array $providers = [])
- {
- $this->cache = $cache ?: new ArrayAdapter();
- $this->registerFunctions();
- foreach ($providers as $provider) {
- $this->registerProvider($provider);
- }
- }
- /**
- * Compiles an expression source code.
- *
- * @param Expression|string $expression The expression to compile
- *
- * @return string The compiled PHP source code
- */
- public function compile($expression, array $names = [])
- {
- return $this->getCompiler()->compile($this->parse($expression, $names)->getNodes())->getSource();
- }
- /**
- * Evaluate an expression.
- *
- * @param Expression|string $expression The expression to compile
- *
- * @return mixed The result of the evaluation of the expression
- */
- public function evaluate($expression, array $values = [])
- {
- return $this->parse($expression, array_keys($values))->getNodes()->evaluate($this->functions, $values);
- }
- /**
- * Parses an expression.
- *
- * @param Expression|string $expression The expression to parse
- *
- * @return ParsedExpression A ParsedExpression instance
- */
- public function parse($expression, array $names)
- {
- if ($expression instanceof ParsedExpression) {
- return $expression;
- }
- asort($names);
- $cacheKeyItems = [];
- foreach ($names as $nameKey => $name) {
- $cacheKeyItems[] = \is_int($nameKey) ? $name : $nameKey.':'.$name;
- }
- $cacheItem = $this->cache->getItem(rawurlencode($expression.'//'.implode('|', $cacheKeyItems)));
- if (null === $parsedExpression = $cacheItem->get()) {
- $nodes = $this->getParser()->parse($this->getLexer()->tokenize((string) $expression), $names);
- $parsedExpression = new ParsedExpression((string) $expression, $nodes);
- $cacheItem->set($parsedExpression);
- $this->cache->save($cacheItem);
- }
- return $parsedExpression;
- }
- /**
- * Validates the syntax of an expression.
- *
- * @param Expression|string $expression The expression to validate
- * @param array|null $names The list of acceptable variable names in the expression, or null to accept any names
- *
- * @throws SyntaxError When the passed expression is invalid
- */
- public function lint($expression, ?array $names): void
- {
- if ($expression instanceof ParsedExpression) {
- return;
- }
- $this->getParser()->lint($this->getLexer()->tokenize((string) $expression), $names);
- }
- /**
- * Registers a function.
- *
- * @param callable $compiler A callable able to compile the function
- * @param callable $evaluator A callable able to evaluate the function
- *
- * @throws \LogicException when registering a function after calling evaluate(), compile() or parse()
- *
- * @see ExpressionFunction
- */
- public function register(string $name, callable $compiler, callable $evaluator)
- {
- if (null !== $this->parser) {
- throw new \LogicException('Registering functions after calling evaluate(), compile() or parse() is not supported.');
- }
- $this->functions[$name] = ['compiler' => $compiler, 'evaluator' => $evaluator];
- }
- public function addFunction(ExpressionFunction $function)
- {
- $this->register($function->getName(), $function->getCompiler(), $function->getEvaluator());
- }
- public function registerProvider(ExpressionFunctionProviderInterface $provider)
- {
- foreach ($provider->getFunctions() as $function) {
- $this->addFunction($function);
- }
- }
- protected function registerFunctions()
- {
- $this->addFunction(ExpressionFunction::fromPhp('constant'));
- }
- private function getLexer(): Lexer
- {
- if (null === $this->lexer) {
- $this->lexer = new Lexer();
- }
- return $this->lexer;
- }
- private function getParser(): Parser
- {
- if (null === $this->parser) {
- $this->parser = new Parser($this->functions);
- }
- return $this->parser;
- }
- private function getCompiler(): Compiler
- {
- if (null === $this->compiler) {
- $this->compiler = new Compiler($this->functions);
- }
- return $this->compiler->reset();
- }
- }
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