Add Functionlike interface

src/FunctionLike.php

@@ -0,0 +1,13 @@
+<?php
+/*---------------------------------------------------------------------------------------------
+ * Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+namespace Microsoft\PhpParser;
+
+/**
+ * Interface for recognizing functions easily.
+ * Each Node that implements this interface can be considered a function.
+ */
+interface FunctionLike {}

src/Node/Expression/AnonymousFunctionCreationExpression.php

@@ -6,14 +6,15 @@
 
 namespace Microsoft\PhpParser\Node\Expression;
 
+use Microsoft\PhpParser\FunctionLike;
 use Microsoft\PhpParser\Node\Expression;
 use Microsoft\PhpParser\Node\FunctionBody;
 use Microsoft\PhpParser\Node\FunctionHeader;
 use Microsoft\PhpParser\Node\FunctionReturnType;
 use Microsoft\PhpParser\Node\FunctionUseClause;
 use Microsoft\PhpParser\Token;
 
-class AnonymousFunctionCreationExpression extends Expression {
+class AnonymousFunctionCreationExpression extends Expression implements FunctionLike {
     /** @var Token | null */
     public $staticModifier;
 

src/Node/MethodDeclaration.php

@@ -6,11 +6,12 @@
 
 namespace Microsoft\PhpParser\Node;
 
+use Microsoft\PhpParser\FunctionLike;
 use Microsoft\PhpParser\Node;
 use Microsoft\PhpParser\Token;
 use Microsoft\PhpParser\TokenKind;
 
-class MethodDeclaration extends Node {
+class MethodDeclaration extends Node implements FunctionLike {
     /** @var Token[] */
     public $modifiers;
 

src/Node/Statement/FunctionDeclaration.php

@@ -6,14 +6,15 @@
 
 namespace Microsoft\PhpParser\Node\Statement;
 
+use Microsoft\PhpParser\FunctionLike;
 use Microsoft\PhpParser\NamespacedNameInterface;
 use Microsoft\PhpParser\NamespacedNameTrait;
 use Microsoft\PhpParser\Node\FunctionBody;
 use Microsoft\PhpParser\Node\FunctionHeader;
 use Microsoft\PhpParser\Node\FunctionReturnType;
 use Microsoft\PhpParser\Node\StatementNode;
 
-class FunctionDeclaration extends StatementNode implements NamespacedNameInterface {
+class FunctionDeclaration extends StatementNode implements NamespacedNameInterface, FunctionLike {
     use FunctionHeader, FunctionReturnType, FunctionBody;
     use NamespacedNameTrait;