From ef59f160c738d65c6ae9cedf8b5bb33fdb0543e6 Mon Sep 17 00:00:00 2001
From: Yorick Peterse <yorickpeterse@gmail.com>
Date: Wed, 29 Jul 2015 09:44:14 +0200
Subject: [PATCH] XPath compiler support for true()/false()

---
 lib/oga/xpath/compiler.rb | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/lib/oga/xpath/compiler.rb b/lib/oga/xpath/compiler.rb
index bf0bc39..4cf0785 100644
--- a/lib/oga/xpath/compiler.rb
+++ b/lib/oga/xpath/compiler.rb
@@ -399,6 +399,39 @@ module Oga
           .or(send_message('raise', string("Undefined XPath variable: #{name}")))
       end
 
+      ##
+      # Delegates function calls to specific handlers.
+      #
+      # @param [AST::Node] ast
+      # @param [Oga::Ruby::Node] input
+      # @return [Oga::Ruby::Node]
+      #
+      def on_call(ast, input, &block)
+        name, test = *ast.children
+
+        handler = name.gsub('-', '_')
+
+        send(:"on_call_#{handler}", test, input, &block)
+      end
+
+      ##
+      # Processes the `true()` function call.
+      #
+      # @see [#on_call]
+      #
+      def on_call_true(ast, input)
+        literal('true')
+      end
+
+      ##
+      # Processes the `false()` function call.
+      #
+      # @see [#on_call]
+      #
+      def on_call_false(ast, input)
+        literal('false')
+      end
+
       private
 
       # @param [#to_s] value