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\Yield_;
Chris@13: use PhpParser\Node\FunctionLike;
Chris@13: use Psy\Exception\FatalErrorException;
Chris@13: 
Chris@13: class FunctionContextPass extends CodeCleanerPass
Chris@13: {
Chris@13:     /** @var int */
Chris@13:     private $functionDepth;
Chris@13: 
Chris@13:     /**
Chris@13:      * @param array $nodes
Chris@13:      */
Chris@13:     public function beforeTraverse(array $nodes)
Chris@13:     {
Chris@13:         $this->functionDepth = 0;
Chris@13:     }
Chris@13: 
Chris@13:     public function enterNode(Node $node)
Chris@13:     {
Chris@13:         if ($node instanceof FunctionLike) {
Chris@13:             $this->functionDepth++;
Chris@13: 
Chris@13:             return;
Chris@13:         }
Chris@13: 
Chris@13:         // node is inside function context
Chris@13:         if ($this->functionDepth !== 0) {
Chris@13:             return;
Chris@13:         }
Chris@13: 
Chris@13:         // It causes fatal error.
Chris@13:         if ($node instanceof Yield_) {
Chris@13:             $msg = 'The "yield" expression can only be used inside a function';
Chris@13:             throw new FatalErrorException($msg, 0, E_ERROR, null, $node->getLine());
Chris@13:         }
Chris@13:     }
Chris@13: 
Chris@13:     /**
Chris@13:      * @param \PhpParser\Node $node
Chris@13:      */
Chris@13:     public function leaveNode(Node $node)
Chris@13:     {
Chris@13:         if ($node instanceof FunctionLike) {
Chris@13:             $this->functionDepth--;
Chris@13:         }
Chris@13:     }
Chris@13: }