4 * This file is part of Psy Shell.
6 * (c) 2012-2018 Justin Hileman
8 * For the full copyright and license information, please view the LICENSE
9 * file that was distributed with this source code.
12 namespace Psy\CodeCleaner;
15 use PhpParser\Node\Expr;
16 use PhpParser\Node\Expr\Exit_;
17 use PhpParser\Node\Expr\New_;
18 use PhpParser\Node\Name\FullyQualified as FullyQualifiedName;
19 use PhpParser\Node\Stmt;
20 use PhpParser\Node\Stmt\Break_;
21 use PhpParser\Node\Stmt\Expression;
22 use PhpParser\Node\Stmt\If_;
23 use PhpParser\Node\Stmt\Namespace_;
24 use PhpParser\Node\Stmt\Return_;
25 use PhpParser\Node\Stmt\Switch_;
28 * Add an implicit "return" to the last statement, provided it can be returned.
30 class ImplicitReturnPass extends CodeCleanerPass
37 public function beforeTraverse(array $nodes)
39 return $this->addImplicitReturn($nodes);
47 private function addImplicitReturn(array $nodes)
49 // If nodes is empty, it can't have a return value.
51 return [new Return_(new New_(new FullyQualifiedName('Psy\CodeCleaner\NoReturnValue')))];
56 // Special case a few types of statements to add an implicit return
57 // value (even though they technically don't have any return value)
58 // because showing a return value in these instances is useful and not
60 if ($last instanceof If_) {
61 $last->stmts = $this->addImplicitReturn($last->stmts);
63 foreach ($last->elseifs as $elseif) {
64 $elseif->stmts = $this->addImplicitReturn($elseif->stmts);
68 $last->else->stmts = $this->addImplicitReturn($last->else->stmts);
70 } elseif ($last instanceof Switch_) {
71 foreach ($last->cases as $case) {
72 // only add an implicit return to cases which end in break
73 $caseLast = end($case->stmts);
74 if ($caseLast instanceof Break_) {
75 $case->stmts = $this->addImplicitReturn(array_slice($case->stmts, 0, -1));
76 $case->stmts[] = $caseLast;
79 } elseif ($last instanceof Expr && !($last instanceof Exit_)) {
80 $nodes[count($nodes) - 1] = new Return_($last, [
81 'startLine' => $last->getLine(),
82 'endLine' => $last->getLine(),
84 } elseif ($last instanceof Expression && !($last->expr instanceof Exit_)) {
86 $nodes[count($nodes) - 1] = new Return_($last->expr, [
87 'startLine' => $last->getLine(),
88 'endLine' => $last->getLine(),
90 } elseif ($last instanceof Namespace_) {
91 $last->stmts = $this->addImplicitReturn($last->stmts);
94 // Return a "no return value" for all non-expression statements, so that
95 // PsySH can suppress the `null` that `eval()` returns otherwise.
97 // Note that statements special cased above (if/elseif/else, switch)
98 // _might_ implicitly return a value before this catch-all return is
101 // We're not adding a fallback return after namespace statements,
102 // because code outside namespace statements doesn't really work, and
103 // there's already an implicit return in the namespace statement anyway.
104 if (self::isNonExpressionStmt($last)) {
105 $nodes[] = new Return_(new New_(new FullyQualifiedName('Psy\CodeCleaner\NoReturnValue')));
112 * Check whether a given node is a non-expression statement.
114 * As of PHP Parser 4.x, Expressions are now instances of Stmt as well, so
115 * we'll exclude them here.
121 private static function isNonExpressionStmt(Node $node)
123 return $node instanceof Stmt &&
124 !$node instanceof Expression &&
125 !$node instanceof Return_ &&
126 !$node instanceof Namespace_;