Chris@13: <?php
Chris@13: 
Chris@13: /*
Chris@13:  * This file is part of Psy Shell.
Chris@13:  *
Chris@13:  * (c) 2012-2018 Justin Hileman
Chris@13:  *
Chris@13:  * For the full copyright and license information, please view the LICENSE
Chris@13:  * file that was distributed with this source code.
Chris@13:  */
Chris@13: 
Chris@13: namespace Psy\CodeCleaner;
Chris@13: 
Chris@13: use PhpParser\Node;
Chris@13: use PhpParser\Node\Expr\Empty_;
Chris@13: use PhpParser\Node\Expr\Variable;
Chris@13: use Psy\Exception\ParseErrorException;
Chris@13: 
Chris@13: /**
Chris@13:  * Validate that the user did not call the language construct `empty()` on a
Chris@13:  * statement in PHP < 5.5.
Chris@16:  *
Chris@16:  * @codeCoverageIgnore
Chris@13:  */
Chris@13: class LegacyEmptyPass extends CodeCleanerPass
Chris@13: {
Chris@13:     private $atLeastPhp55;
Chris@13: 
Chris@13:     public function __construct()
Chris@13:     {
Chris@17:         $this->atLeastPhp55 = \version_compare(PHP_VERSION, '5.5', '>=');
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * Validate use of empty in PHP < 5.5.
Chris@13:      *
Chris@13:      * @throws ParseErrorException if the user used empty with anything but a variable
Chris@13:      *
Chris@13:      * @param Node $node
Chris@13:      */
Chris@13:     public function enterNode(Node $node)
Chris@13:     {
Chris@13:         if ($this->atLeastPhp55) {
Chris@13:             return;
Chris@13:         }
Chris@13: 
Chris@13:         if (!$node instanceof Empty_) {
Chris@13:             return;
Chris@13:         }
Chris@13: 
Chris@13:         if (!$node->expr instanceof Variable) {
Chris@17:             $msg = \sprintf('syntax error, unexpected %s', $this->getUnexpectedThing($node->expr));
Chris@13: 
Chris@13:             throw new ParseErrorException($msg, $node->expr->getLine());
Chris@13:         }
Chris@13:     }
Chris@13: 
Chris@13:     private function getUnexpectedThing(Node $node)
Chris@13:     {
Chris@13:         switch ($node->getType()) {
Chris@13:             case 'Scalar_String':
Chris@13:             case 'Scalar_LNumber':
Chris@13:             case 'Scalar_DNumber':
Chris@17:                 return \json_encode($node->value);
Chris@13: 
Chris@13:             case 'Expr_ConstFetch':
Chris@13:                 return (string) $node->name;
Chris@13: 
Chris@13:             default:
Chris@13:                 return $node->getType();
Chris@13:         }
Chris@13:     }
Chris@13: }