Added explicit doc start/end tokens for the emitter, and set it so that if you try to write after you've already written a full doc, it writes a doc start and continues

include/yaml-cpp/emitter.h

@@ -75,6 +75,8 @@ namespace YAML
 		void PostAtomicWrite();
 		void EmitSeparationIfNecessary();
 		
+		void EmitBeginDoc();
+		void EmitEndDoc();
 		void EmitBeginSeq();
 		void EmitEndSeq();
 		void EmitBeginMap();

include/yaml-cpp/emittermanip.h

@@ -41,6 +41,10 @@ namespace YAML
 		Hex,
 		Oct,
 		
+		// document manipulators
+		BeginDoc,
+		EndDoc,
+		
 		// sequence manipulators
 		BeginSeq,
 		EndSeq,

src/emitter.cpp

@@ -102,6 +102,12 @@ namespace YAML
 			return *this;
 		
 		switch(value) {
+			case BeginDoc:
+				EmitBeginDoc();
+				break;
+			case EndDoc:
+				EmitEndDoc();
+				break;
 			case BeginSeq:
 				EmitBeginSeq();
 				break;
@@ -157,8 +163,8 @@ namespace YAML
 			case ES_WRITING_DOC:
 				return true;
 			case ES_DONE_WITH_DOC:
-				m_pState->SetError("Write called on finished document");
+				EmitBeginDoc();
-				return true;
+				return false;
 				
 				// block sequence
 			case ES_WAITING_FOR_BLOCK_SEQ_ENTRY:
@@ -320,6 +326,47 @@ namespace YAML
 		m_pState->UnsetSeparation();
 	}
 	
+	// EmitBeginDoc
+	void Emitter::EmitBeginDoc()
+	{
+		if(!good())
+			return;
+		
+		EMITTER_STATE curState = m_pState->GetCurState();
+		if(curState != ES_WAITING_FOR_DOC && curState != ES_WRITING_DOC && curState != ES_DONE_WITH_DOC) {
+			m_pState->SetError("Unexpected begin document");
+			return;
+		}
+		
+		if(curState == ES_WRITING_DOC || curState == ES_DONE_WITH_DOC)
+			m_stream << '\n';		
+		m_stream << "---\n";
+
+		m_pState->UnsetSeparation();
+		m_pState->SwitchState(ES_WAITING_FOR_DOC);
+	}
+	
+	// EmitEndDoc
+	void Emitter::EmitEndDoc()
+	{
+		if(!good())
+			return;
+
+		
+		EMITTER_STATE curState = m_pState->GetCurState();
+		if(curState != ES_WAITING_FOR_DOC && curState != ES_WRITING_DOC && curState != ES_DONE_WITH_DOC) {
+			m_pState->SetError("Unexpected end document");
+			return;
+		}
+		
+		if(curState == ES_WRITING_DOC || curState == ES_DONE_WITH_DOC)
+			m_stream << '\n';		
+		m_stream << "...\n";
+		
+		m_pState->UnsetSeparation();
+		m_pState->SwitchState(ES_WAITING_FOR_DOC);
+	}
+
 	// EmitBeginSeq
 	void Emitter::EmitBeginSeq()
 	{

test/emittertests.cpp

@@ -777,6 +777,28 @@ namespace Test
 			"- Y\n- Y\n- y\n- N\n- N\n- n";
 		}
 		
+		void DocStartAndEnd(YAML::Emitter& out, std::string& desiredOutput)
+		{
+			out << YAML::BeginDoc;
+			out << YAML::BeginSeq << 1 << 2 << 3 << YAML::EndSeq;
+			out << YAML::BeginDoc;
+			out << "Hi there!";
+			out << YAML::EndDoc;
+			out << YAML::EndDoc;
+			out << YAML::EndDoc;
+			out << YAML::BeginDoc;
+			out << YAML::VerbatimTag("foo") << "bar";
+			desiredOutput = "---\n- 1\n- 2\n- 3\n---\nHi there!\n...\n...\n...\n---\n!<foo> bar";
+		}
+		
+		void ImplicitDocStart(YAML::Emitter& out, std::string& desiredOutput)
+		{
+			out << "Hi";
+			out << "Bye";
+			out << "Oops";
+			desiredOutput = "Hi\n---\nBye\n---\nOops";
+		}
+
 		////////////////////////////////////////////////////////////////////////////////////////////////////////
 		// incorrect emitting
 		
@@ -870,6 +892,7 @@ namespace Test
 			std::string desiredOutput;
 			test(out, desiredOutput);
 			std::string output = out.c_str();
+			std::string lastError = out.GetLastError();
 
 			if(output == desiredOutput) {
 				try {
@@ -888,6 +911,8 @@ namespace Test
 				std::cout << output << "<<<\n";
 				std::cout << "Desired output:\n";
 				std::cout << desiredOutput << "<<<\n";				
+				if(!out.good())
+					std::cout << "Emitter error: " << lastError << "\n";
 			}
 			total++;
 		}
@@ -978,6 +1003,8 @@ namespace Test
 		RunEmitterTest(&Emitter::ColonAtEndOfScalar, "colon at end of scalar", passed, total);
 		RunEmitterTest(&Emitter::ColonAsScalar, "colon as scalar", passed, total);
 		RunEmitterTest(&Emitter::BoolFormatting, "bool formatting", passed, total);
+		RunEmitterTest(&Emitter::DocStartAndEnd, "doc start and end", passed, total);
+		RunEmitterTest(&Emitter::ImplicitDocStart, "implicit doc start", passed, total);
 		
 		RunEmitterErrorTest(&Emitter::ExtraEndSeq, "extra EndSeq", passed, total);
 		RunEmitterErrorTest(&Emitter::ExtraEndMap, "extra EndMap", passed, total);