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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;
/**
* Represents a function that can be used in an expression.
*
* A function is defined by two PHP callables. The callables are used
* by the language to compile and/or evaluate the function.
*
* The "compiler" function is used at compilation time and must return a
* PHP representation of the function call (it receives the function
* arguments as arguments).
*
* The "evaluator" function is used for expression evaluation and must return
* the value of the function call based on the values defined for the
* expression (it receives the values as a first argument and the function
* arguments as remaining arguments).
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class ExpressionFunction
{
private $name;
private $compiler;
private $evaluator;
/**
* @param string $name The function name
* @param callable $compiler A callable able to compile the function
* @param callable $evaluator A callable able to evaluate the function
*/
public function __construct(string $name, callable $compiler, callable $evaluator)
{
$this->name = $name;
$this->compiler = $compiler;
$this->evaluator = $evaluator;
}
public function getName()
{
return $this->name;
}
public function getCompiler()
{
return $this->compiler;
}
public function getEvaluator()
{
return $this->evaluator;
}
/**
* Creates an ExpressionFunction from a PHP function name.
*
* @param string $phpFunctionName The PHP function name
* @param string|null $expressionFunctionName The expression function name (default: same than the PHP function name)
*
* @return self
*
* @throws \InvalidArgumentException if given PHP function name does not exist
* @throws \InvalidArgumentException if given PHP function name is in namespace
* and expression function name is not defined
*/
public static function fromPhp($phpFunctionName, $expressionFunctionName = null)
{
$phpFunctionName = ltrim($phpFunctionName, '\\');
if (!\function_exists($phpFunctionName)) {
throw new \InvalidArgumentException(sprintf('PHP function "%s" does not exist.', $phpFunctionName));
}
$parts = explode('\\', $phpFunctionName);
if (!$expressionFunctionName && \count($parts) > 1) {
throw new \InvalidArgumentException(sprintf('An expression function name must be defined when PHP function "%s" is namespaced.', $phpFunctionName));
}
$compiler = function (...$args) use ($phpFunctionName) {
return sprintf('\%s(%s)', $phpFunctionName, implode(', ', $args));
};
$evaluator = function ($p, ...$args) use ($phpFunctionName) {
return $phpFunctionName(...$args);
};
return new self($expressionFunctionName ?: end($parts), $compiler, $evaluator);
}
}