From 214f1130165ada0ee47d2711aef6c11b6dad28c5 Mon Sep 17 00:00:00 2001
From: Arthur Baars <aibaars@github.com>
Date: Wed, 17 Feb 2021 13:36:01 +0100
Subject: [PATCH] AST: add getChild/getParent method

---
 ql/src/codeql_ruby/AST.qll              | 6 ++++++
 ql/src/codeql_ruby/ast/internal/AST.qll | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/ql/src/codeql_ruby/AST.qll b/ql/src/codeql_ruby/AST.qll
index 11c41330aa4..28a05877c5f 100644
--- a/ql/src/codeql_ruby/AST.qll
+++ b/ql/src/codeql_ruby/AST.qll
@@ -36,4 +36,10 @@ class AstNode extends @ast_node {
 
   /** Gets the location of this node. */
   final Location getLocation() { result = range.getLocation() }
+
+  /** Gets a child node of this `AstNode`. */
+  final AstNode getAChild() { range.child(_, result) }
+
+  /** Gets the parent of this `AstNode`, if this node is not a root node. */
+  final AstNode getParent() { result.getAChild() = this }
 }
diff --git a/ql/src/codeql_ruby/ast/internal/AST.qll b/ql/src/codeql_ruby/ast/internal/AST.qll
index b09355148a1..8fb1159c83f 100644
--- a/ql/src/codeql_ruby/ast/internal/AST.qll
+++ b/ql/src/codeql_ruby/ast/internal/AST.qll
@@ -11,6 +11,8 @@ module AstNode {
     abstract string toString();
 
     Location getLocation() { result = generated.getLocation() }
+
+    predicate child(string label, AstNode::Range child) { none() }
   }
 
   // TODO: Remove