Added support for emitting and represeting null

include/conversion.h

@@ -4,6 +4,7 @@
 #define CONVERSION_H_62B23520_7C8E_11DE_8A39_0800200C9A66
 
 
+#include "null.h"
 #include <string>
 #include <sstream>
 
@@ -37,6 +38,9 @@ namespace YAML
 	template <>
 	bool Converter<bool>::Convert(const std::string& input, bool& output);
 	
+	template <>
+	bool Converter<_Null>::Convert(const std::string& input, _Null& output);
+	
 	template <>
 	bool Converter<std::wstring>::Convert(const std::string& input, std::wstring& output);
 }

include/emitter.h

@@ -6,6 +6,7 @@
 
 #include "emittermanip.h"
 #include "ostream.h"
+#include "null.h"
 #include <memory>
 #include <string>
 
@@ -51,6 +52,7 @@ namespace YAML
 		Emitter& Write(const _Alias& alias);
 		Emitter& Write(const _Anchor& anchor);
 		Emitter& Write(const _Comment& comment);
+		Emitter& Write(const _Null& null);
 		
 	private:
 		enum ATOMIC_TYPE { AT_SCALAR, AT_SEQ, AT_BLOCK_SEQ, AT_FLOW_SEQ, AT_MAP, AT_BLOCK_MAP, AT_FLOW_MAP };

include/null.h

+#pragma once
+
+#ifndef NULL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define NULL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+
+namespace YAML
+{
+	struct _Null {};
+	extern _Null Null;
+}
+
+#endif // NULL_H_62B23520_7C8E_11DE_8A39_0800200C9A66
\ No newline at end of file

src/conversion.cpp

@@ -83,6 +83,12 @@ namespace YAML
 		return false;
 	}
 	
+	template <>
+	bool Converter<_Null>::Convert(const std::string& input, _Null& /*output*/)
+	{
+		return input.empty() || input == "~" || input == "null" || input == "Null" || input == "NULL";
+	}
+
 	template <>
 	bool Converter<std::wstring>::Convert(const std::string& input, std::wstring& output)
 	{

src/emitter.cpp

@@ -666,4 +666,16 @@ namespace YAML
 		Utils::WriteComment(m_stream, comment.content, m_pState->GetPostCommentIndent());
 		return *this;
 	}
+
+	Emitter& Emitter::Write(const _Null& /*null*/)
+	{
+		if(!good())
+			return *this;
+		
+		PreAtomicWrite();
+		EmitSeparationIfNecessary();
+		m_stream << "~";
+		PostAtomicWrite();
+		return *this;
+	}
 }

src/node.cpp

@@ -10,6 +10,7 @@
 #include "aliascontent.h"
 #include "iterpriv.h"
 #include "emitter.h"
+#include <stdexcept>
 
 namespace YAML
 {
@@ -85,6 +86,9 @@ namespace YAML
 				m_pContent = new Map;
 				break;
 			default:
+//				std::stringstream str;
+//				str << TokenNames[pScanner->peek().type];
+//				throw std::runtime_error(str.str());
 				break;
 		}
 

src/null.cpp

+#include "null.h"
+
+namespace YAML
+{
+	_Null Null;
+}

yaml-reader/emittertests.cpp

@@ -425,6 +425,19 @@ namespace Test
 			desiredOutput = "-\n  key 1: value 1\n  key 2: [a, b, c]\n-\n  ? [1, 2]\n  :\n    a: b";
 		}
 
+		void Null(YAML::Emitter& out, std::string& desiredOutput)
+		{
+			out << YAML::BeginSeq;
+			out << YAML::Null;
+			out << YAML::BeginMap;
+			out << YAML::Key << "null value" << YAML::Value << YAML::Null;
+			out << YAML::Key << YAML::Null << YAML::Value << "null key";
+			out << YAML::EndMap;
+			out << YAML::EndSeq;
+			
+			desiredOutput = "- ~\n-\n  null value: ~\n  ~: null key";
+		}
+
 		////////////////////////////////////////////////////////////////////////////////////////////////////////
 		// incorrect emitting
 		

yaml-reader/tests.cpp

@@ -351,6 +351,7 @@ namespace Test
 		RunEmitterTest(&Emitter::Indentation, "indentation", passed);
 		RunEmitterTest(&Emitter::SimpleGlobalSettings, "simple global settings", passed);
 		RunEmitterTest(&Emitter::ComplexGlobalSettings, "complex global settings", passed);
+		RunEmitterTest(&Emitter::Null, "null", passed);
 		
 		RunEmitterErrorTest(&Emitter::ExtraEndSeq, "extra EndSeq", passed);
 		RunEmitterErrorTest(&Emitter::ExtraEndMap, "extra EndMap", passed);

yaml-reader/tests.h

@@ -68,6 +68,7 @@ namespace Test {
 		void Indentation(YAML::Emitter& out, std::string& desiredOutput);
 		void SimpleGlobalSettings(YAML::Emitter& out, std::string& desiredOutput);
 		void ComplexGlobalSettings(YAML::Emitter& out, std::string& desiredOutput);
+		void Null(YAML::Emitter& out, std::string& desiredOutput);
 
 		// incorrect emitting
 		void ExtraEndSeq(YAML::Emitter& out, std::string& desiredError);