From f23ece2f6f48b32d902616298c1eae22a65b9cd6 Mon Sep 17 00:00:00 2001
From: Elijah Miller <elijah.miller@gmail.com>
Date: Wed, 25 Mar 2026 12:48:44 -0400
Subject: [PATCH] Initial stab at walk_nodes simplification.

---
 feel/lib/feel/literal_expression.rb | 46 ++---------------------------
 feel/lib/feel/nodes.rb              | 11 +++++++
 2 files changed, 13 insertions(+), 44 deletions(-)

diff --git a/feel/lib/feel/literal_expression.rb b/feel/lib/feel/literal_expression.rb
index a2430f6..6fa8624 100644
--- a/feel/lib/feel/literal_expression.rb
+++ b/feel/lib/feel/literal_expression.rb
@@ -34,54 +34,12 @@ def functions
 
     def named_functions
       return [] if text.blank?
-
-      # Initialize a set to hold the qualified names
-      function_names = Set.new
-
-      # Define a lambda for the recursive function
-      walk_tree = lambda do |node|
-        # If the node is a qualified name, add it to the set
-        if node.is_a?(FEEL::FunctionInvocation)
-          function_names << node.fn_name.text_value
-        end
-
-        # Recursively walk the child nodes
-        node.elements&.each do |child|
-          walk_tree.call(child)
-        end
-      end
-
-      # Start walking the tree from the root
-      walk_tree.call(tree)
-
-      # Return the array of functions
-      function_names.to_a
+      FEEL::Node.walk_nodes(tree).select { |node| node.is_a?(FEEL::FunctionInvocation) }.map { |node| node.fn_name.text_value }.uniq
     end
 
     def named_variables
       return [] if text.blank?
-
-      # Initialize a set to hold the qualified names
-      qualified_names = Set.new
-
-      # Define a lambda for the recursive function
-      walk_tree = lambda do |node|
-        # If the node is a qualified name, add it to the set
-        if node.is_a?(FEEL::QualifiedName)
-          qualified_names << node.text_value
-        end
-
-        # Recursively walk the child nodes
-        node.elements&.each do |child|
-          walk_tree.call(child)
-        end
-      end
-
-      # Start walking the tree from the root
-      walk_tree.call(tree)
-
-      # Return the array of qualified names
-      qualified_names.to_a
+      FEEL::Node.walk_nodes(tree).select { |node| node.is_a?(FEEL::QualifiedName) }.map(&:text_value).uniq
     end
 
     def self.builtin_functions
diff --git a/feel/lib/feel/nodes.rb b/feel/lib/feel/nodes.rb
index 8d5c70c..c6bc5f8 100644
--- a/feel/lib/feel/nodes.rb
+++ b/feel/lib/feel/nodes.rb
@@ -2,6 +2,17 @@
 
 module FEEL
   class Node < Treetop::Runtime::SyntaxNode
+    def self.walk_nodes(node, &block)
+      return enum_for(:walk_nodes, node) unless block_given?
+
+      yield node
+      node.elements&.each { |child| walk_nodes(child, &block) }
+    end
+
+    def walk_nodes(&block)
+      self.class.walk_nodes(self, &block)
+    end
+
     #
     # Takes a context hash and returns an array of qualified names
     # { "person": { "name": { "first": "Eric", "last": "Carlson" }, "age": 60 } } => ["person", "person.name.first", "person.name.last", "person.age"]