Add FinderVisitor

Allows finding nodes based on a filter callback.

lib/PhpParser/NodeVisitor/FinderVisitor.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace PhpParser\NodeVisitor;
+
+use PhpParser\Node;
+use PhpParser\NodeVisitorAbstract;
+
+/**
+ * This visitor can be used to find and collect all nodes satisfying some criterion determined by
+ * a filter callback.
+ */
+class FinderVisitor extends NodeVisitorAbstract {
+    /** @var callable Filter callback */
+    protected $filterCallback;
+    /** @var Node[] Found nodes */
+    protected $foundNodes;
+
+    public function __construct(callable $filterCallback) {
+        $this->filterCallback = $filterCallback;
+    }
+
+    /**
+     * Get found nodes satisfying the filter callback.
+     *
+     * Nodes are returned in pre-order.
+     *
+     * @return Node[] Found nodes
+     */
+    public function getFoundNodes() {
+        return $this->foundNodes;
+    }
+
+    public function beforeTraverse(array $nodes) {
+        $this->foundNodes = [];
+    }
+
+    public function enterNode(Node $node) {
+        $filterCallback = $this->filterCallback;
+        if ($filterCallback($node)) {
+            $this->foundNodes[] = $node;
+        }
+    }
+}

test/PhpParser/NodeVisitor/FinderVisitorTest.php

@@ -0,0 +1,52 @@
+<?php
+
+namespace PhpParser\NodeVisitor;
+
+use PhpParser\Node;
+use PhpParser\Node\Expr;
+use PhpParser\NodeTraverser;
+
+class FinderVisitorTest extends \PHPUnit_Framework_TestCase {
+    public function testFindVariables() {
+        $traverser = new NodeTraverser();
+        $visitor = new FinderVisitor(function(Node $node) {
+            return $node instanceof Node\Expr\Variable;
+        });
+        $traverser->addVisitor($visitor);
+
+        $assign = new Expr\Assign(new Expr\Variable('a'), new Expr\BinaryOp\Concat(
+            new Expr\Variable('b'), new Expr\Variable('c')
+        ));
+        $stmts = [new Node\Stmt\Expression($assign)];
+
+        $traverser->traverse($stmts);
+        $this->assertSame([
+            $assign->var,
+            $assign->expr->left,
+            $assign->expr->right,
+        ], $visitor->getFoundNodes());
+    }
+
+    public function testFindAll() {
+        $traverser = new NodeTraverser();
+        $visitor = new FinderVisitor(function(Node $node) {
+            return true; // All nodes
+        });
+        $traverser->addVisitor($visitor);
+
+        $assign = new Expr\Assign(new Expr\Variable('a'), new Expr\BinaryOp\Concat(
+            new Expr\Variable('b'), new Expr\Variable('c')
+        ));
+        $stmts = [new Node\Stmt\Expression($assign)];
+
+        $traverser->traverse($stmts);
+        $this->assertSame([
+            $stmts[0],
+            $assign,
+            $assign->var,
+            $assign->expr,
+            $assign->expr->left,
+            $assign->expr->right,
+        ], $visitor->getFoundNodes());
+    }
+}