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<?php
/*
* This file is part of the webmozart/expression package.
*
* (c) Bernhard Schussek <bschussek@gmail.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Webmozart\Expression\Constraint;
use Webmozart\Expression\Expression;
use Webmozart\Expression\Logic\Literal;
/**
* Checks that a value is empty.
*
* @since 1.0
*
* @author Bernhard Schussek <bschussek@gmail.com>
*/
final class IsEmpty extends Literal
{
/**
* {@inheritdoc}
*/
public function evaluate($value)
{
return empty($value);
}
/**
* {@inheritdoc}
*/
public function equivalentTo(Expression $other)
{
// Since this class is final, we can check with instanceof
return $other instanceof $this;
}
/**
* {@inheritdoc}
*/
public function toString()
{
return 'empty()';
}
}