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[yaffs-website] / vendor / psy / psysh / src / CodeCleaner / ImplicitReturnPass.php

diff --git a/vendor/psy/psysh/src/CodeCleaner/ImplicitReturnPass.php b/vendor/psy/psysh/src/CodeCleaner/ImplicitReturnPass.php
new file mode 100644 (file)
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+++ b/vendor/psy/psysh/src/CodeCleaner/ImplicitReturnPass.php
@@ -0,0 +1,128 @@
+<?php
+
+/*
+ * This file is part of Psy Shell.
+ *
+ * (c) 2012-2018 Justin Hileman
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Psy\CodeCleaner;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\Exit_;
+use PhpParser\Node\Expr\New_;
+use PhpParser\Node\Name\FullyQualified as FullyQualifiedName;
+use PhpParser\Node\Stmt;
+use PhpParser\Node\Stmt\Break_;
+use PhpParser\Node\Stmt\Expression;
+use PhpParser\Node\Stmt\If_;
+use PhpParser\Node\Stmt\Namespace_;
+use PhpParser\Node\Stmt\Return_;
+use PhpParser\Node\Stmt\Switch_;
+
+/**
+ * Add an implicit "return" to the last statement, provided it can be returned.
+ */
+class ImplicitReturnPass extends CodeCleanerPass
+{
+    /**
+     * @param array $nodes
+     *
+     * @return array
+     */
+    public function beforeTraverse(array $nodes)
+    {
+        return $this->addImplicitReturn($nodes);
+    }
+
+    /**
+     * @param array $nodes
+     *
+     * @return array
+     */
+    private function addImplicitReturn(array $nodes)
+    {
+        // If nodes is empty, it can't have a return value.
+        if (empty($nodes)) {
+            return [new Return_(new New_(new FullyQualifiedName('Psy\CodeCleaner\NoReturnValue')))];
+        }
+
+        $last = end($nodes);
+
+        // Special case a few types of statements to add an implicit return
+        // value (even though they technically don't have any return value)
+        // because showing a return value in these instances is useful and not
+        // very surprising.
+        if ($last instanceof If_) {
+            $last->stmts = $this->addImplicitReturn($last->stmts);
+
+            foreach ($last->elseifs as $elseif) {
+                $elseif->stmts = $this->addImplicitReturn($elseif->stmts);
+            }
+
+            if ($last->else) {
+                $last->else->stmts = $this->addImplicitReturn($last->else->stmts);
+            }
+        } elseif ($last instanceof Switch_) {
+            foreach ($last->cases as $case) {
+                // only add an implicit return to cases which end in break
+                $caseLast = end($case->stmts);
+                if ($caseLast instanceof Break_) {
+                    $case->stmts = $this->addImplicitReturn(array_slice($case->stmts, 0, -1));
+                    $case->stmts[] = $caseLast;
+                }
+            }
+        } elseif ($last instanceof Expr && !($last instanceof Exit_)) {
+            $nodes[count($nodes) - 1] = new Return_($last, [
+                'startLine' => $last->getLine(),
+                'endLine'   => $last->getLine(),
+            ]);
+        } elseif ($last instanceof Expression && !($last->expr instanceof Exit_)) {
+            // For PHP Parser 4.x
+            $nodes[count($nodes) - 1] = new Return_($last->expr, [
+                'startLine' => $last->getLine(),
+                'endLine'   => $last->getLine(),
+            ]);
+        } elseif ($last instanceof Namespace_) {
+            $last->stmts = $this->addImplicitReturn($last->stmts);
+        }
+
+        // Return a "no return value" for all non-expression statements, so that
+        // PsySH can suppress the `null` that `eval()` returns otherwise.
+        //
+        // Note that statements special cased above (if/elseif/else, switch)
+        // _might_ implicitly return a value before this catch-all return is
+        // reached.
+        //
+        // We're not adding a fallback return after namespace statements,
+        // because code outside namespace statements doesn't really work, and
+        // there's already an implicit return in the namespace statement anyway.
+        if (self::isNonExpressionStmt($last)) {
+            $nodes[] = new Return_(new New_(new FullyQualifiedName('Psy\CodeCleaner\NoReturnValue')));
+        }
+
+        return $nodes;
+    }
+
+    /**
+     * Check whether a given node is a non-expression statement.
+     *
+     * As of PHP Parser 4.x, Expressions are now instances of Stmt as well, so
+     * we'll exclude them here.
+     *
+     * @param Node $node
+     *
+     * @return bool
+     */
+    private static function isNonExpressionStmt(Node $node)
+    {
+        return $node instanceof Stmt &&
+            !$node instanceof Expression &&
+            !$node instanceof Return_ &&
+            !$node instanceof Namespace_;
+    }
+}