From d506dae91451a7467abb2d14929591d345c88141 Mon Sep 17 00:00:00 2001
From: Jesse Beder <jbeder+github@gmail.com>
Date: Fri, 31 Jul 2009 05:07:21 +0000
Subject: [PATCH] Added IsNull function

---
 include/null.h              | 4 ++++
 src/null.cpp                | 6 ++++++
 yaml-reader/parsertests.cpp | 7 ++-----
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/null.h b/include/null.h
index c7c43cc..7036f98 100644
--- a/include/null.h
+++ b/include/null.h
@@ -6,10 +6,14 @@
 
 namespace YAML
 {
+	class Node;
+	
 	struct _Null {};
 	inline bool operator == (const _Null&, const _Null&) { return true; }
 	inline bool operator != (const _Null&, const _Null&) { return false; }
 	
+	bool IsNull(const Node& node);
+	
 	extern _Null Null;
 }
 
diff --git a/src/null.cpp b/src/null.cpp
index 853d49a..faa05fb 100644
--- a/src/null.cpp
+++ b/src/null.cpp
@@ -1,6 +1,12 @@
 #include "null.h"
+#include "node.h"
 
 namespace YAML
 {
 	_Null Null;
+
+	bool IsNull(const Node& node)
+	{
+		return node.Read(Null);
+	}
 }
diff --git a/yaml-reader/parsertests.cpp b/yaml-reader/parsertests.cpp
index 721ceb9..3b2e28d 100644
--- a/yaml-reader/parsertests.cpp
+++ b/yaml-reader/parsertests.cpp
@@ -261,8 +261,7 @@ namespace Test
 			doc[0] >> output;
 			if(output != "hello")
 				return false;
-			doc[1] >> output;
-			if(output != "~")
+			if(!IsNull(doc[1]))
 				return false;
 			doc[2] >> output;
 			if(output != "world")
@@ -297,9 +296,7 @@ namespace Test
 			YAML::Node doc;
 			parser.GetNextDocument(doc);
 			
-			std::string output;
-			doc["empty value"] >> output;
-			if(output != "~")
+			if(!IsNull(doc["empty value"]))
 				return false;
 			
 			return true;