Reintegrated the event-api branch (second iteration) into the rtweeks21-staging branch.

include/aliasmanager.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#ifndef ALIASMANAGER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define ALIASMANAGER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include "anchor.h"
+#include <map>
+
+namespace YAML
+{
+	class Node;
+	
+	class AliasManager
+	{
+	public:
+		AliasManager();
+		
+		void RegisterReference(const Node& node);
+		
+		const Node *LookupReference(const Node& node) const;
+		anchor_t LookupAnchor(const Node& node) const;
+		
+	private:
+		const Node *_LookupReference(const Node& oldIdentity) const;
+		anchor_t _CreateNewAnchor();
+		
+	private:
+		typedef std::map<const Node*, const Node*> NodeByNode;
+		NodeByNode m_newIdentityByOldIdentity;
+		
+		typedef std::map<const Node*, anchor_t> AnchorByIdentity;
+		AnchorByIdentity m_anchorByIdentity;
+		
+		anchor_t m_curAnchor;
+	};
+}
+
+#endif // ALIASMANAGER_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/anchor.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#ifndef ANCHOR_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define ANCHOR_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include <cstddef>
+
+namespace YAML
+{
+	typedef std::size_t anchor_t;
+	const anchor_t NullAnchor = 0;
+}
+
+#endif // ANCHOR_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/emitfromevents.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#ifndef EMITFROMEVENTS_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define EMITFROMEVENTS_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include "eventhandler.h"
+#include <stack>
+
+namespace YAML
+{
+	class Emitter;
+	
+	class EmitFromEvents: public EventHandler
+	{
+	public:
+		EmitFromEvents(Emitter& emitter);
+		
+		virtual void OnDocumentStart(const Mark& mark);
+		virtual void OnDocumentEnd();
+		
+		virtual void OnNull(const std::string& tag, anchor_t anchor);
+		virtual void OnAlias(const Mark& mark, anchor_t anchor);
+		virtual void OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value);
+		
+		virtual void OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+		virtual void OnSequenceEnd();
+		
+		virtual void OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+		virtual void OnMapEnd();
+		
+	private:
+		void BeginNode();
+		void EmitProps(const std::string& tag, anchor_t anchor);
+		
+	private:
+		Emitter& m_emitter;
+		
+		struct State { enum value { WaitingForSequenceEntry, WaitingForKey, WaitingForValue }; };
+		std::stack<State::value> m_stateStack;
+	};
+}
+
+#endif // EMITFROMEVENTS_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/eventhandler.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#ifndef EVENTHANDLER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define EVENTHANDLER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include "anchor.h"
+#include <string>
+
+namespace YAML
+{
+	struct Mark;
+	
+	class EventHandler
+	{
+	public:
+		virtual ~EventHandler() {}
+
+		virtual void OnDocumentStart(const Mark& mark) = 0;
+		virtual void OnDocumentEnd() = 0;
+		
+		virtual void OnNull(const std::string& tag, anchor_t anchor) = 0;
+		virtual void OnAlias(const Mark& mark, anchor_t anchor) = 0;
+		virtual void OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value) = 0;
+
+		virtual void OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor) = 0;
+		virtual void OnSequenceEnd() = 0;
+
+		virtual void OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor) = 0;
+		virtual void OnMapEnd() = 0;
+	};
+}
+
+#endif // EVENTHANDLER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+

include/graphbuilder.h

@@ -0,0 +1,117 @@
+#ifndef GRAPHBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define GRAPHBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include <string>
+
+namespace YAML
+{
+  struct Mark;
+  
+  // GraphBuilderInterface
+  // . Abstraction of node creation
+  // . pParentNode is always NULL or the return value of one of the NewXXX()
+  //   functions.
+  class GraphBuilderInterface
+  {
+  public:
+    // Create and return a new node with a null value.
+    virtual void *NewNull(const std::string& tag, void *pParentNode) = 0;
+    
+    // Create and return a new node with the given tag and value.
+    virtual void *NewScalar(const Mark& mark, const std::string& tag, void *pParentNode, const std::string& value) = 0;
+    
+    // Create and return a new sequence node
+    virtual void *NewSequence(const Mark& mark, const std::string& tag, void *pParentNode) = 0;
+    // Add pNode to pSequence.  pNode was created with one of the NewXxx()
+    // functions and pSequence with NewSequence().
+    virtual void AppendToSequence(void *pSequence, void *pNode) = 0;
+    // Note that no moew entries will be added to pSequence
+    virtual void SequenceComplete(void *pSequence) {(void)pSequence;}
+    
+    // Create and return a new map node
+    virtual void *NewMap(const Mark& mark, const std::string& tag, void *pParentNode) = 0;
+    // Add the pKeyNode => pValueNode mapping to pMap.  pKeyNode and pValueNode
+    // were created with one of the NewXxx() methods and pMap with NewMap().
+    virtual void AssignInMap(void *pMap, void *pKeyNode, void *pValueNode) = 0;
+    // Note that no more assignments will be made in pMap
+    virtual void MapComplete(void *pMap) {(void)pMap;}
+    
+    // Return the node that should be used in place of an alias referencing
+    // pNode (pNode by default)
+    virtual void *AnchorReference(const Mark& mark, void *pNode) {(void)mark; return pNode;}
+  };
+  
+  // Typesafe wrapper for GraphBuilderInterface.  Assumes that Impl defines
+  // Node, Sequence, and Map types.  Sequence and Map must derive from Node
+  // (unless Node is defined as void).  Impl must also implement function with
+  // all of the same names as the virtual functions in GraphBuilderInterface
+  // -- including the ones with default implementations -- but with the
+  // prototypes changed to accept an explicit Node*, Sequence*, or Map* where
+  // appropriate.
+  template <class Impl>
+  class GraphBuilder : public GraphBuilderInterface
+  {
+  public:
+    typedef typename Impl::Node Node;
+    typedef typename Impl::Sequence Sequence;
+    typedef typename Impl::Map Map;
+    
+    GraphBuilder(Impl& impl) : m_impl(impl)
+    {
+      Map* pMap = NULL;
+      Sequence* pSeq = NULL;
+      Node* pNode = NULL;
+      
+      // Type consistency checks
+      pNode = pMap;
+      pNode = pSeq;
+    }
+    
+    GraphBuilderInterface& AsBuilderInterface() {return *this;}
+    
+    virtual void *NewNull(const std::string& tag, void* pParentNode) {
+      return CheckType<Node>(m_impl.NewNull(tag, AsNode(pParentNode)));
+    }
+    
+    virtual void *NewScalar(const Mark& mark, const std::string& tag, void *pParentNode, const std::string& value) {
+      return CheckType<Node>(m_impl.NewScalar(mark, tag, AsNode(pParentNode), value));
+    }
+    
+    virtual void *NewSequence(const Mark& mark, const std::string& tag, void *pParentNode) {
+      return CheckType<Sequence>(m_impl.NewSequence(mark, tag, AsNode(pParentNode)));
+    }
+    virtual void AppendToSequence(void *pSequence, void *pNode) {
+      m_impl.AppendToSequence(AsSequence(pSequence), AsNode(pNode));
+    }
+    virtual void SequenceComplete(void *pSequence) {
+      m_impl.SequenceComplete(AsSequence(pSequence));
+    }
+    
+    virtual void *NewMap(const Mark& mark, const std::string& tag, void *pParentNode) {
+      return CheckType<Map>(m_impl.NewMap(mark, tag, AsNode(pParentNode)));
+    }
+    virtual void AssignInMap(void *pMap, void *pKeyNode, void *pValueNode) {
+      m_impl.AssignInMap(AsMap(pMap), AsNode(pKeyNode), AsNode(pValueNode));
+    }
+    virtual void MapComplete(void *pMap) {
+      m_impl.MapComplete(AsMap(pMap));
+    }
+    
+    virtual void *AnchorReference(const Mark& mark, void *pNode) {
+      return CheckType<Node>(m_impl.AnchorReference(mark, AsNode(pNode)));
+    }
+  
+  private:
+    Impl& m_impl;
+    
+    // Static check for pointer to T
+    template <class T, class U>
+    static T* CheckType(U* p) {return p;}
+    
+    static Node *AsNode(void *pNode) {return static_cast<Node*>(pNode);}
+    static Sequence *AsSequence(void *pSeq) {return static_cast<Sequence*>(pSeq);}
+    static Map *AsMap(void *pMap) {return static_cast<Map*>(pMap);}
+  };
+}
+
+#endif // GRAPHBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/node.h

@@ -17,10 +17,12 @@
 
 namespace YAML
 {
+	class AliasManager;
 	class Content;
 	class Scanner;
 	class Emitter;
-	struct ParserState;
+	class EventHandler;
+	struct NodeProperties;
 
 	enum CONTENT_TYPE { CT_NONE, CT_SCALAR, CT_SEQUENCE, CT_MAP };
 
@@ -32,7 +34,16 @@ namespace YAML
 
 		void Clear();
 		std::auto_ptr<Node> Clone() const;
-		void Parse(Scanner *pScanner, ParserState& state);
+		void EmitEvents(EventHandler& eventHandler) const;
+		void EmitEvents(AliasManager& am, EventHandler& eventHandler) const;
+
+		void Init(CONTENT_TYPE type, const Mark& mark, const std::string& tag);
+		void InitNull(const std::string& tag);
+		void InitAlias(const Mark& mark, const Node& identity);
+		
+		void SetData(const std::string& data);
+		void Append(std::auto_ptr<Node> pNode);
+		void Insert(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue);
 
 		CONTENT_TYPE GetType() const;
 
@@ -98,18 +109,9 @@ namespace YAML
 		template <typename T>
 		const Node *FindValueForKey(const T& key) const;
 
-		// helper for cloning
-		Node(const Mark& mark, const std::string& anchor, const std::string& tag, const Content *pContent);
-
-		// helpers for parsing
-		void ParseHeader(Scanner *pScanner, ParserState& state);
-		void ParseTag(Scanner *pScanner, ParserState& state);
-		void ParseAnchor(Scanner *pScanner, ParserState& state);
-		void ParseAlias(Scanner *pScanner, ParserState& state);
-
 	private:
 		Mark m_mark;
-		std::string m_anchor, m_tag;
+		std::string m_tag;
 		Content *m_pContent;
 		bool m_alias;
 		const Node *m_pIdentity;

include/nodeproperties.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#ifndef NODEPROPERTIES_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define NODEPROPERTIES_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+namespace YAML
+{
+	struct NodeProperties {
+		std::string tag;
+		std::string anchor;
+	};
+}
+
+#endif // NODEPROPERTIES_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/parser.h

@@ -4,19 +4,20 @@
 #define PARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
 
 
-#include "node.h"
+#include "graphbuilder.h"
 #include "noncopyable.h"
 #include <ios>
-#include <string>
-#include <vector>
-#include <map>
 #include <memory>
 
 namespace YAML
 {
-	class Scanner;
+	struct Directives;
-	struct ParserState;
+	struct Mark;
 	struct Token;
+	class EventHandler;
+	class GraphBuilderInterface;
+	class Node;
+	class Scanner;
 
 	class Parser: private noncopyable
 	{
@@ -28,6 +29,18 @@ namespace YAML
 		operator bool() const;
 
 		void Load(std::istream& in);
+		bool HandleNextDocument(EventHandler& eventHandler);
+		
+		void *BuildNextDocumentGraph(GraphBuilderInterface& graphBuilder);
+		template <class Builder>
+		typename Builder::Node *BuildNextDocumentGraph(Builder& graphBuilder)
+		{
+			GraphBuilder<Builder> wrapper(graphBuilder); // Must be lvalue to make C++ happy
+			return static_cast<typename Builder::Node *>(
+				BuildNextDocumentGraph(wrapper.AsBuilderInterface())
+			);
+		}
+		
 		bool GetNextDocument(Node& document);
 		void PrintTokens(std::ostream& out);
 
@@ -39,7 +52,7 @@ namespace YAML
 		
 	private:
 		std::auto_ptr<Scanner> m_pScanner;
-		std::auto_ptr<ParserState> m_pState;
+		std::auto_ptr<Directives> m_pDirectives;
 	};
 }
 

src/aliascontent.cpp

@@ -2,25 +2,10 @@
 
 namespace YAML
 {
-	AliasContent::AliasContent(Content* pNodeContent)
+	AliasContent::AliasContent(Content* pNodeContent): m_pRef(pNodeContent)
-		: m_pRef(pNodeContent)
 	{
 	}
 
-	Content *AliasContent::Clone() const
-	{
-		return 0; // TODO: how to clone an alias?
-	}
-
-	void AliasContent::Parse(Scanner * /*pScanner*/, ParserState& /*state*/)
-	{
-	}
-
-	void AliasContent::Write(Emitter&) const
-	{
-		// no content (just an alias)
-	}
-
 	bool AliasContent::GetBegin(std::vector <Node *>::const_iterator& i) const
 	{
 		return m_pRef->GetBegin(i);
@@ -71,6 +56,11 @@ namespace YAML
 		return m_pRef->GetScalar(scalar);
 	}
 
+	void AliasContent::EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const
+	{
+		m_pRef->EmitEvents(am, eventHandler, mark, tag, anchor);
+	}
+
 	int AliasContent::Compare(Content *pContent)
 	{
 		return m_pRef->Compare(pContent);

src/aliascontent.h

@@ -13,11 +13,6 @@ namespace YAML
 	public:
 		AliasContent(Content *pNodeContent);
 
-		virtual Content *Clone() const;
-
-		virtual void Parse(Scanner* pScanner, ParserState& state);
-		virtual void Write(Emitter&) const;
-
 		virtual bool GetBegin(std::vector <Node *>::const_iterator&) const;
 		virtual bool GetBegin(std::map <Node *, Node *, ltnode>::const_iterator&) const;
 		virtual bool GetEnd(std::vector <Node *>::const_iterator&) const;
@@ -29,6 +24,7 @@ namespace YAML
 		virtual bool IsSequence() const;
 
 		virtual bool GetScalar(std::string& s) const;
+		virtual void EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const;
 
 		virtual int Compare(Content *);
 		virtual int Compare(Scalar *);

src/aliasmanager.cpp

@@ -0,0 +1,45 @@
+#include "aliasmanager.h"
+#include "node.h"
+#include <cassert>
+#include <sstream>
+
+namespace YAML
+{
+	AliasManager::AliasManager(): m_curAnchor(0)
+	{
+	}
+
+	void AliasManager::RegisterReference(const Node& node)
+	{
+		const Node *pIdentity = node.Identity();
+		m_newIdentityByOldIdentity.insert(std::make_pair(pIdentity, &node));
+		m_anchorByIdentity.insert(std::make_pair(&node, _CreateNewAnchor()));
+	}
+	
+	const Node *AliasManager::LookupReference(const Node& node) const
+	{
+		const Node *pIdentity = node.Identity();
+		return _LookupReference(*pIdentity);
+	}
+	
+	anchor_t AliasManager::LookupAnchor(const Node& node) const
+	{
+		AnchorByIdentity::const_iterator it = m_anchorByIdentity.find(&node);
+		if(it == m_anchorByIdentity.end())
+			assert(false); // TODO: throw
+		return it->second;
+	}
+
+	const Node *AliasManager::_LookupReference(const Node& oldIdentity) const
+	{
+		NodeByNode::const_iterator it = m_newIdentityByOldIdentity.find(&oldIdentity);
+		if(it == m_newIdentityByOldIdentity.end())
+			return 0;
+		return it->second;
+	}
+	
+	anchor_t AliasManager::_CreateNewAnchor()
+	{
+		return ++m_curAnchor;
+	}
+}

src/collectionstack.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#ifndef COLLECTIONSTACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define COLLECTIONSTACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+
+#include <stack>
+#include <cassert>
+
+namespace YAML
+{
+	struct CollectionType {
+		enum value { None, BlockMap, BlockSeq, FlowMap, FlowSeq, CompactMap };
+	};
+
+	class CollectionStack
+	{
+	public:
+		CollectionType::value GetCurCollectionType() const {
+			if(collectionStack.empty())
+				return CollectionType::None;
+			return collectionStack.top();
+		}
+		
+		void PushCollectionType(CollectionType::value type) { collectionStack.push(type); }
+		void PopCollectionType(CollectionType::value type) { assert(type == GetCurCollectionType()); collectionStack.pop(); }
+		
+	private:
+		std::stack<CollectionType::value> collectionStack;
+	};
+}
+
+#endif // COLLECTIONSTACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/content.cpp

@@ -0,0 +1,21 @@
+#include "content.h"
+#include "node.h"
+#include <cassert>
+
+namespace YAML
+{
+	void Content::SetData(const std::string&)
+	{
+		assert(false); // TODO: throw
+	}
+
+	void Content::Append(std::auto_ptr<Node>)
+	{
+		assert(false); // TODO: throw
+	}
+
+	void Content::Insert(std::auto_ptr<Node>, std::auto_ptr<Node>)
+	{
+		assert(false); // TODO: throw
+	}
+}

src/content.h

@@ -4,21 +4,24 @@
 #define CONTENT_H_62B23520_7C8E_11DE_8A39_0800200C9A66
 
 
-#include <vector>
+#include "anchor.h"
-#include <map>
-#include "parserstate.h"
 #include "exceptions.h"
 #include "ltnode.h"
+#include <map>
+#include <memory>
+#include <vector>
 
 namespace YAML
 {
-	class Scanner;
+	struct Mark;
-	class Parser;
+	struct NodeProperties;
+	class AliasManager;
+	class EventHandler;
+	class Map;
 	class Node;
 	class Scalar;
+	class Scanner;
 	class Sequence;
-	class Map;
-	class Emitter;
 
 	class Content
 	{
@@ -26,11 +29,6 @@ namespace YAML
 		Content() {}
 		virtual ~Content() {}
 
-		virtual Content *Clone() const = 0;
-
-		virtual void Parse(Scanner *pScanner, ParserState& state) = 0;
-		virtual void Write(Emitter& out) const = 0;
-
 		virtual bool GetBegin(std::vector <Node *>::const_iterator&) const { return false; }
 		virtual bool GetBegin(std::map <Node *, Node *, ltnode>::const_iterator&) const { return false; }
 		virtual bool GetEnd(std::vector <Node *>::const_iterator&) const { return false; }
@@ -41,6 +39,11 @@ namespace YAML
 		virtual bool IsMap() const { return false; }
 		virtual bool IsSequence() const { return false; }
 		
+		virtual void SetData(const std::string& data);
+		virtual void Append(std::auto_ptr<Node> pNode);
+		virtual void Insert(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue);
+		virtual void EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const = 0;
+
 		// extraction
 		virtual bool GetScalar(std::string&) const { return false; }
 

src/directives.cpp

@@ -1,8 +1,8 @@
-#include "parserstate.h"
+#include "directives.h"
 
 namespace YAML
 {
-	ParserState::ParserState()
+	Directives::Directives()
 	{
 		// version
 		version.isDefault = true;
@@ -10,7 +10,7 @@ namespace YAML
 		version.minor = 2;
 	}
 	
-	const std::string ParserState::TranslateTagHandle(const std::string& handle) const
+	const std::string Directives::TranslateTagHandle(const std::string& handle) const
 	{
 		std::map <std::string, std::string>::const_iterator it = tags.find(handle);
 		if(it == tags.end()) {

src/directives.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#ifndef DIRECTIVES_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define DIRECTIVES_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+
+#include <string>
+#include <map>
+
+namespace YAML
+{
+	struct Version {
+		bool isDefault;
+		int major, minor;
+	};
+	
+	struct Directives {
+		Directives();
+		
+		const std::string TranslateTagHandle(const std::string& handle) const;
+
+		Version version;
+		std::map<std::string, std::string> tags;
+	};
+}
+
+#endif // DIRECTIVES_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/emitfromevents.cpp

@@ -0,0 +1,106 @@
+#include "emitfromevents.h"
+#include "emitter.h"
+#include "null.h"
+#include <cassert>
+#include <sstream>
+
+namespace {
+	std::string ToString(YAML::anchor_t anchor) {
+		std::stringstream stream;
+		stream << anchor;
+		return stream.str();
+	}
+}
+
+namespace YAML
+{
+	EmitFromEvents::EmitFromEvents(Emitter& emitter): m_emitter(emitter)
+	{
+	}
+	
+	void EmitFromEvents::OnDocumentStart(const Mark&)
+	{
+	}
+	
+	void EmitFromEvents::OnDocumentEnd()
+	{
+	}
+	
+	void EmitFromEvents::OnNull(const std::string& tag, anchor_t anchor)
+	{
+		BeginNode();
+		EmitProps(tag, anchor);
+		if(tag.empty())
+			m_emitter << Null;
+	}
+	
+	void EmitFromEvents::OnAlias(const Mark&, anchor_t anchor)
+	{
+		BeginNode();
+		m_emitter << Alias(ToString(anchor));
+	}
+	
+	void EmitFromEvents::OnScalar(const Mark&, const std::string& tag, anchor_t anchor, const std::string& value)
+	{
+		BeginNode();
+		EmitProps(tag, anchor);
+		m_emitter << value;
+	}
+	
+	void EmitFromEvents::OnSequenceStart(const Mark&, const std::string& tag, anchor_t anchor)
+	{
+		BeginNode();
+		EmitProps(tag, anchor);
+		m_emitter << BeginSeq;
+		m_stateStack.push(State::WaitingForSequenceEntry);
+	}
+	
+	void EmitFromEvents::OnSequenceEnd()
+	{
+		m_emitter << EndSeq;
+		assert(m_stateStack.top() == State::WaitingForSequenceEntry);
+		m_stateStack.pop();
+	}
+	
+	void EmitFromEvents::OnMapStart(const Mark&, const std::string& tag, anchor_t anchor)
+	{
+		BeginNode();
+		EmitProps(tag, anchor);
+		m_emitter << BeginMap;
+		m_stateStack.push(State::WaitingForKey);
+	}
+
+	void EmitFromEvents::OnMapEnd()
+	{
+		m_emitter << EndMap;
+		assert(m_stateStack.top() == State::WaitingForKey);
+		m_stateStack.pop();
+	}
+
+	void EmitFromEvents::BeginNode()
+	{
+		if(m_stateStack.empty())
+			return;
+		
+		switch(m_stateStack.top()) {
+			case State::WaitingForKey:
+				m_emitter << Key;
+				m_stateStack.top() = State::WaitingForValue;
+				break;
+			case State::WaitingForValue:
+				m_emitter << Value;
+				m_stateStack.top() = State::WaitingForKey;
+				break;
+			default:
+				break;
+		}
+	}
+	
+	void EmitFromEvents::EmitProps(const std::string& tag, anchor_t anchor)
+	{
+		if(!tag.empty())
+			m_emitter << VerbatimTag(tag);
+		if(anchor)
+			m_emitter << Anchor(ToString(anchor));
+	}
+}

src/graphbuilderadapter.cpp

@@ -0,0 +1,96 @@
+#include "graphbuilderadapter.h"
+
+namespace YAML
+{
+  int GraphBuilderAdapter::ContainerFrame::sequenceMarker;
+  
+  void GraphBuilderAdapter::OnNull(const std::string& tag, anchor_t anchor)
+  {
+    void *pParent = GetCurrentParent();
+    void *pNode = m_builder.NewNull(tag, pParent);
+    RegisterAnchor(anchor, pNode);
+    
+    DispositionNode(pNode);
+  }
+  
+  void GraphBuilderAdapter::OnAlias(const Mark& mark, anchor_t anchor)
+  {
+    void *pReffedNode = m_anchors[anchor];
+    DispositionNode(m_builder.AnchorReference(mark, pReffedNode));
+  }
+  
+  void GraphBuilderAdapter::OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value)
+  {
+    void *pParent = GetCurrentParent();
+    void *pNode = m_builder.NewScalar(mark, tag, pParent, value);
+    RegisterAnchor(anchor, pNode);
+    
+    DispositionNode(pNode);
+  }
+  
+  void GraphBuilderAdapter::OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+  {
+    void *pNode = m_builder.NewSequence(mark, tag, GetCurrentParent());
+    m_containers.push(ContainerFrame(pNode));
+    RegisterAnchor(anchor, pNode);
+  }
+  
+  void GraphBuilderAdapter::OnSequenceEnd()
+  {
+    void *pSequence = m_containers.top().pContainer;
+    m_containers.pop();
+    
+    DispositionNode(pSequence);
+  }
+  
+  void GraphBuilderAdapter::OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+  {
+    void *pNode = m_builder.NewMap(mark, tag, GetCurrentParent());
+    m_containers.push(ContainerFrame(pNode, m_pKeyNode));
+    m_pKeyNode = NULL;
+    RegisterAnchor(anchor, pNode);
+  }
+  
+  void GraphBuilderAdapter::OnMapEnd()
+  {
+    void *pMap = m_containers.top().pContainer;
+    m_pKeyNode = m_containers.top().pPrevKeyNode;
+    m_containers.pop();
+    DispositionNode(pMap);
+  }
+  
+  void *GraphBuilderAdapter::GetCurrentParent() const
+  {
+    if (m_containers.empty()) {
+      return NULL;
+    }
+    return m_containers.top().pContainer;
+  }
+  
+  void GraphBuilderAdapter::RegisterAnchor(anchor_t anchor, void *pNode)
+  {
+    if (anchor) {
+      m_anchors[anchor] = pNode;
+    }
+  }
+  
+  void GraphBuilderAdapter::DispositionNode(void *pNode)
+  {
+    if (m_containers.empty()) {
+      m_pRootNode = pNode;
+      return;
+    }
+    
+    void *pContainer = m_containers.top().pContainer;
+    if (m_containers.top().isMap()) {
+      if (m_pKeyNode) {
+        m_builder.AssignInMap(pContainer, m_pKeyNode, pNode);
+        m_pKeyNode = NULL;
+      } else {
+        m_pKeyNode = pNode;
+      }
+    } else {
+      m_builder.AppendToSequence(pContainer, pNode);
+    }
+  }
+}

src/graphbuilderadapter.h

@@ -0,0 +1,67 @@
+#ifndef GRAPHBUILDERADAPTER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define GRAPHBUILDERADAPTER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include <map>
+#include <stack>
+#include "eventhandler.h"
+#include "graphbuilder.h"
+
+namespace YAML
+{
+  class GraphBuilderAdapter : public EventHandler
+  {
+  public:
+    GraphBuilderAdapter(GraphBuilderInterface& builder)
+    : m_builder(builder), m_pRootNode(NULL), m_pKeyNode(NULL)
+    {
+    }
+    
+    virtual void OnDocumentStart(const Mark& mark) {(void)mark;}
+    virtual void OnDocumentEnd() {}
+    
+    virtual void OnNull(const std::string& tag, anchor_t anchor);
+    virtual void OnAlias(const Mark& mark, anchor_t anchor);
+    virtual void OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value);
+    
+    virtual void OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+    virtual void OnSequenceEnd();
+    
+    virtual void OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+    virtual void OnMapEnd();
+    
+    void *RootNode() const {return m_pRootNode;}
+  
+  private:
+    struct ContainerFrame
+    {
+      ContainerFrame(void *pSequence)
+      : pContainer(pSequence), pPrevKeyNode(&sequenceMarker)
+      {}
+      ContainerFrame(void *pMap, void* pPrevKeyNode)
+      : pContainer(pMap), pPrevKeyNode(pPrevKeyNode)
+      {}
+      
+      void *pContainer;
+      void *pPrevKeyNode;
+      
+      bool isMap() const {return pPrevKeyNode != &sequenceMarker;}
+    
+    private:
+      static int sequenceMarker;
+    };
+    typedef std::stack<ContainerFrame> ContainerStack;
+    typedef std::map<anchor_t, void*> AnchorMap;
+    
+    GraphBuilderInterface& m_builder;
+    ContainerStack m_containers;
+    AnchorMap m_anchors;
+    void *m_pRootNode;
+    void *m_pKeyNode;
+    
+    void *GetCurrentParent() const;
+    void RegisterAnchor(anchor_t anchor, void *pNode);
+    void DispositionNode(void *pNode);
+  };
+}
+
+#endif // GRAPHBUILDERADAPTER_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/map.cpp

@@ -1,9 +1,7 @@
 #include "map.h"
 #include "node.h"
-#include "scanner.h"
+#include "eventhandler.h"
-#include "token.h"
 #include "exceptions.h"
-#include "emitter.h"
 
 namespace YAML
 {
@@ -11,15 +9,6 @@ namespace YAML
 	{
 	}
 
-	Map::Map(const node_map& data)
-	{
-		for(node_map::const_iterator it=data.begin();it!=data.end();++it) {
-			std::auto_ptr<Node> pKey = it->first->Clone();
-			std::auto_ptr<Node> pValue = it->second->Clone();
-			AddEntry(pKey, pValue);
-		}
-	}
-
 	Map::~Map()
 	{
 		Clear();
@@ -34,11 +23,6 @@ namespace YAML
 		m_data.clear();
 	}
 
-	Content *Map::Clone() const
-	{
-		return new Map(m_data);
-	}
-	
 	bool Map::GetBegin(std::map <Node *, Node *, ltnode>::const_iterator& it) const
 	{
 		it = m_data.begin();
@@ -56,140 +40,7 @@ namespace YAML
 		return m_data.size();
 	}
 
-	void Map::Parse(Scanner *pScanner, ParserState& state)
+	void Map::Insert(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue)
-	{
-		Clear();
-
-		// split based on start token
-		switch(pScanner->peek().type) {
-			case Token::BLOCK_MAP_START: ParseBlock(pScanner, state); break;
-			case Token::FLOW_MAP_START: ParseFlow(pScanner, state); break;
-			case Token::KEY: ParseCompact(pScanner, state); break;
-			case Token::VALUE: ParseCompactWithNoKey(pScanner, state); break;
-			default: break;
-		}
-	}
-
-	void Map::ParseBlock(Scanner *pScanner, ParserState& state)
-	{
-		// eat start token
-		pScanner->pop();
-		state.PushCollectionType(ParserState::BLOCK_MAP);
-
-		while(1) {
-			if(pScanner->empty())
-				throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP);
-
-			Token token = pScanner->peek();
-			if(token.type != Token::KEY && token.type != Token::VALUE && token.type != Token::BLOCK_MAP_END)
-				throw ParserException(token.mark, ErrorMsg::END_OF_MAP);
-
-			if(token.type == Token::BLOCK_MAP_END) {
-				pScanner->pop();
-				break;
-			}
-
-			std::auto_ptr <Node> pKey(new Node), pValue(new Node);
-			
-			// grab key (if non-null)
-			if(token.type == Token::KEY) {
-				pScanner->pop();
-				pKey->Parse(pScanner, state);
-			}
-
-			// now grab value (optional)
-			if(!pScanner->empty() && pScanner->peek().type == Token::VALUE) {
-				pScanner->pop();
-				pValue->Parse(pScanner, state);
-			}
-
-			AddEntry(pKey, pValue);
-		}
-
-		state.PopCollectionType(ParserState::BLOCK_MAP);
-	}
-
-	void Map::ParseFlow(Scanner *pScanner, ParserState& state)
-	{
-		// eat start token
-		pScanner->pop();
-		state.PushCollectionType(ParserState::FLOW_MAP);
-
-		while(1) {
-			if(pScanner->empty())
-				throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP_FLOW);
-
-			Token& token = pScanner->peek();
-			// first check for end
-			if(token.type == Token::FLOW_MAP_END) {
-				pScanner->pop();
-				break;
-			}
-			
-			std::auto_ptr <Node> pKey(new Node), pValue(new Node);
-
-			// grab key (if non-null)
-			if(token.type == Token::KEY) {
-				pScanner->pop();
-				pKey->Parse(pScanner, state);
-			}
-			
-			// now grab value (optional)
-			if(!pScanner->empty() && pScanner->peek().type == Token::VALUE) {
-				pScanner->pop();
-				pValue->Parse(pScanner, state);
-			}
-			
-			// now eat the separator (or could be a map end, which we ignore - but if it's neither, then it's a bad node)
-			Token& nextToken = pScanner->peek();
-			if(nextToken.type == Token::FLOW_ENTRY)
-				pScanner->pop();
-			else if(nextToken.type != Token::FLOW_MAP_END)
-				throw ParserException(nextToken.mark, ErrorMsg::END_OF_MAP_FLOW);
-
-			AddEntry(pKey, pValue);
-		}
-
-		state.PopCollectionType(ParserState::FLOW_MAP);
-	}
-
-	// ParseCompact
-	// . Single "key: value" pair in a flow sequence
-	void Map::ParseCompact(Scanner *pScanner, ParserState& state)
-	{
-		state.PushCollectionType(ParserState::COMPACT_MAP);
-		std::auto_ptr <Node> pKey(new Node), pValue(new Node);
-
-		// grab key
-		pScanner->pop();
-		pKey->Parse(pScanner, state);
-			
-		// now grab value (optional)
-		if(!pScanner->empty() && pScanner->peek().type == Token::VALUE) {
-			pScanner->pop();
-			pValue->Parse(pScanner, state);
-		}
-			
-		AddEntry(pKey, pValue);
-		state.PopCollectionType(ParserState::COMPACT_MAP);
-	}
-	
-	// ParseCompactWithNoKey
-	// . Single ": value" pair in a flow sequence
-	void Map::ParseCompactWithNoKey(Scanner *pScanner, ParserState& state)
-	{
-		state.PushCollectionType(ParserState::COMPACT_MAP);
-		std::auto_ptr <Node> pKey(new Node), pValue(new Node);
-
-		// grab value
-		pScanner->pop();
-		pValue->Parse(pScanner, state);
-
-		AddEntry(pKey, pValue);
-		state.PopCollectionType(ParserState::COMPACT_MAP);
-	}
-	
-	void Map::AddEntry(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue)
 	{
 		node_map::const_iterator it = m_data.find(pKey.get());
 		if(it != m_data.end())
@@ -198,12 +49,14 @@ namespace YAML
 		m_data[pKey.release()] = pValue.release();
 	}
 
-	void Map::Write(Emitter& out) const
+	void Map::EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const
 	{
-		out << BeginMap;
+		eventHandler.OnMapStart(mark, tag, anchor);
-		for(node_map::const_iterator it=m_data.begin();it!=m_data.end();++it)
+		for(node_map::const_iterator it=m_data.begin();it!=m_data.end();++it) {
-			out << Key << *it->first << Value << *it->second;
+			it->first->EmitEvents(am, eventHandler);
-		out << EndMap;
+			it->second->EmitEvents(am, eventHandler);
+		}
+		eventHandler.OnMapEnd();
 	}
 
 	int Map::Compare(Content *pContent)

src/map.h

@@ -19,17 +19,16 @@ namespace YAML
 
 	public:
 		Map();
-		Map(const node_map& data);
 		virtual ~Map();
 
 		void Clear();
-		virtual Content *Clone() const;
 
 		virtual bool GetBegin(std::map <Node *, Node *, ltnode>::const_iterator& it) const;
 		virtual bool GetEnd(std::map <Node *, Node *, ltnode>::const_iterator& it) const;
 		virtual std::size_t GetSize() const;
-		virtual void Parse(Scanner *pScanner, ParserState& state);
+
-		virtual void Write(Emitter& out) const;
+		virtual void Insert(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue);
+		virtual void EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const;
 
 		virtual bool IsMap() const { return true; }
 
@@ -39,14 +38,6 @@ namespace YAML
 		virtual int Compare(Sequence *) { return 1; }
 		virtual int Compare(Map *pMap);
 
-	private:
-		void ParseBlock(Scanner *pScanner, ParserState& state);
-		void ParseFlow(Scanner *pScanner, ParserState& state);
-		void ParseCompact(Scanner *pScanner, ParserState& state);
-		void ParseCompactWithNoKey(Scanner *pScanner, ParserState& state);
-		
-		void AddEntry(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue);
-
 	private:
 		node_map m_data;
 	};

src/node.cpp

@@ -1,15 +1,20 @@
 #include "node.h"
-#include "token.h"
-#include "scanner.h"
-#include "content.h"
-#include "parser.h"
-#include "scalar.h"
-#include "sequence.h"
-#include "map.h"
 #include "aliascontent.h"
-#include "iterpriv.h"
+#include "aliasmanager.h"
+#include "content.h"
+#include "emitfromevents.h"
 #include "emitter.h"
+#include "eventhandler.h"
+#include "iterpriv.h"
+#include "map.h"
+#include "nodebuilder.h"
+#include "nodeproperties.h"
+#include "scalar.h"
+#include "scanner.h"
+#include "sequence.h"
 #include "tag.h"
+#include "token.h"
+#include <cassert>
 #include <stdexcept>
 
 namespace YAML
@@ -20,17 +25,10 @@ namespace YAML
 		return *pNode1 < *pNode2;
 	}
 
-	Node::Node(): m_pContent(0), m_alias(false), m_pIdentity(this), m_referenced(true)
+	Node::Node(): m_pContent(0), m_alias(false), m_pIdentity(this), m_referenced(false)
 	{
 	}
 
-	Node::Node(const Mark& mark, const std::string& anchor, const std::string& tag, const Content *pContent)
-	: m_mark(mark), m_anchor(anchor), m_tag(tag), m_pContent(0), m_alias(false), m_pIdentity(this), m_referenced(false)
-	{
-		if(pContent)
-			m_pContent = pContent->Clone();
-	}
-
 	Node::~Node()
 	{
 		Clear();
@@ -42,138 +40,105 @@ namespace YAML
 		m_pContent = 0;
 		m_alias = false;
 		m_referenced = false;
-		m_anchor.clear();
 		m_tag.clear();
 	}
 	
 	std::auto_ptr<Node> Node::Clone() const
 	{
-		if(m_alias)
+		std::auto_ptr<Node> pNode(new Node);
-			throw std::runtime_error("yaml-cpp: Can't clone alias");  // TODO: what to do about aliases?
+		NodeBuilder nodeBuilder(*pNode);
-		
+		EmitEvents(nodeBuilder);
-		return std::auto_ptr<Node> (new Node(m_mark, m_anchor, m_tag, m_pContent));
+		return pNode;
 	}
 
-	void Node::Parse(Scanner *pScanner, ParserState& state)
+	void Node::EmitEvents(EventHandler& eventHandler) const
+	{
+		eventHandler.OnDocumentStart(m_mark);
+		AliasManager am;
+		EmitEvents(am, eventHandler);
+		eventHandler.OnDocumentEnd();
+	}
+
+	void Node::EmitEvents(AliasManager& am, EventHandler& eventHandler) const
+	{
+		anchor_t anchor = NullAnchor;
+		if(m_referenced || m_alias) {
+			if(const Node *pOther = am.LookupReference(*this)) {
+				eventHandler.OnAlias(m_mark, am.LookupAnchor(*pOther));
+				return;
+			}
+			
+			am.RegisterReference(*this);
+			anchor = am.LookupAnchor(*this);
+		}
+		
+		if(m_pContent)
+			m_pContent->EmitEvents(am, eventHandler, m_mark, GetTag(), anchor);
+		else
+			eventHandler.OnNull(GetTag(), anchor);
+	}
+
+	void Node::Init(CONTENT_TYPE type, const Mark& mark, const std::string& tag)
 	{
 		Clear();
+		m_mark = mark;
+		m_tag = tag;
+		m_alias = false;
+		m_pIdentity = this;
+		m_referenced = false;
 
-		// an empty node *is* a possibility
+		switch(type) {
-		if(pScanner->empty())
+			case CT_SCALAR:
-			return;
-
-		// save location
-		m_mark = pScanner->peek().mark;
-		
-		// special case: a value node by itself must be a map, with no header
-		if(pScanner->peek().type == Token::VALUE) {
-			m_pContent = new Map;
-			m_pContent->Parse(pScanner, state);
-			return;
-		}
-
-		ParseHeader(pScanner, state);
-
-		// is this an alias? if so, its contents are an alias to
-		// a previously defined anchor
-		if(m_alias) {
-			// the scanner throws an exception if it doesn't know this anchor name
-			const Node *pReferencedNode = pScanner->Retrieve(m_anchor);
-			m_pIdentity = pReferencedNode;
-
-			// mark the referenced node for the sake of the client code
-			pReferencedNode->m_referenced = true;
-
-			// use of an Alias object keeps the referenced content from
-			// being deleted twice
-			Content *pAliasedContent = pReferencedNode->m_pContent;
-			if(pAliasedContent)
-				m_pContent = new AliasContent(pAliasedContent);
-			
-			return;
-		}
-
-		// now split based on what kind of node we should be
-		switch(pScanner->peek().type) {
-			case Token::SCALAR:
 				m_pContent = new Scalar;
 				break;
-			case Token::FLOW_SEQ_START:
+			case CT_SEQUENCE:
-			case Token::BLOCK_SEQ_START:
 				m_pContent = new Sequence;
 				break;
-			case Token::FLOW_MAP_START:
+			case CT_MAP:
-			case Token::BLOCK_MAP_START:
-				m_pContent = new Map;
-				break;
-			case Token::KEY:
-				// compact maps can only go in a flow sequence
-				if(state.GetCurCollectionType() == ParserState::FLOW_SEQ)
 				m_pContent = new Map;
 				break;
 			default:
+				m_pContent = 0;
 				break;
 		}
-
-		// Have to save anchor before parsing to allow for aliases as
-		// contained node (recursive structure)
-		if(!m_anchor.empty())
-			pScanner->Save(m_anchor, this);
-
-		if(m_pContent)
-			m_pContent->Parse(pScanner, state);
 	}
 
-	// ParseHeader
+	void Node::InitNull(const std::string& tag)
-	// . Grabs any tag, alias, or anchor tokens and deals with them.
-	void Node::ParseHeader(Scanner *pScanner, ParserState& state)
 	{
-		while(1) {
+		Clear();
-			if(pScanner->empty())
+		m_tag = tag;
-				return;
-
-			switch(pScanner->peek().type) {
-				case Token::TAG: ParseTag(pScanner, state); break;
-				case Token::ANCHOR: ParseAnchor(pScanner, state); break;
-				case Token::ALIAS: ParseAlias(pScanner, state); break;
-				default: return;
-			}
-		}
-	}
-
-	void Node::ParseTag(Scanner *pScanner, ParserState& state)
-	{
-		Token& token = pScanner->peek();
-		if(m_tag != "")
-			throw ParserException(token.mark, ErrorMsg::MULTIPLE_TAGS);
-
-		Tag tag(token);
-		m_tag = tag.Translate(state);
-		pScanner->pop();
-	}
-	
-	void Node::ParseAnchor(Scanner *pScanner, ParserState& /*state*/)
-	{
-		Token& token = pScanner->peek();
-		if(m_anchor != "")
-			throw ParserException(token.mark, ErrorMsg::MULTIPLE_ANCHORS);
-
-		m_anchor = token.value;
 		m_alias = false;
-		pScanner->pop();
+		m_pIdentity = this;
+		m_referenced = false;
 	}
 
-	void Node::ParseAlias(Scanner *pScanner, ParserState& /*state*/)
+	void Node::InitAlias(const Mark& mark, const Node& identity)
 	{
-		Token& token = pScanner->peek();
+		Clear();
-		if(m_anchor != "")
+		m_mark = mark;
-			throw ParserException(token.mark, ErrorMsg::MULTIPLE_ALIASES);
-		if(m_tag != "")
-			throw ParserException(token.mark, ErrorMsg::ALIAS_CONTENT);
-
-		m_anchor = token.value;
 		m_alias = true;
-		pScanner->pop();
+		m_pIdentity = &identity;
+		if(identity.m_pContent)
+			m_pContent = new AliasContent(identity.m_pContent);
+		identity.m_referenced = true;
+	}
+
+	void Node::SetData(const std::string& data)
+	{
+		assert(m_pContent); // TODO: throw
+		m_pContent->SetData(data);
+	}
+
+	void Node::Append(std::auto_ptr<Node> pNode)
+	{
+		assert(m_pContent); // TODO: throw
+		m_pContent->Append(pNode);
+	}
+	
+	void Node::Insert(std::auto_ptr<Node> pKey, std::auto_ptr<Node> pValue)
+	{
+		assert(m_pContent); // TODO: throw
+		m_pContent->Insert(pKey, pValue);
 	}
 
 	CONTENT_TYPE Node::GetType() const
@@ -261,23 +226,8 @@ namespace YAML
 
 	Emitter& operator << (Emitter& out, const Node& node)
 	{
-		// write anchor/alias
+		EmitFromEvents emitFromEvents(out);
-		if(node.m_anchor != "") {
+		node.EmitEvents(emitFromEvents);
-			if(node.m_alias)
-				out << Alias(node.m_anchor);
-			else
-				out << Anchor(node.m_anchor);
-		}
-
-		if(node.m_tag != "")
-			out << VerbatimTag(node.m_tag);
-
-		// write content
-		if(node.m_pContent)
-			node.m_pContent->Write(out);
-		else if(!node.m_alias)
-			out << Null;
-
 		return out;
 	}
 

src/nodebuilder.cpp

@@ -0,0 +1,142 @@
+#include "nodebuilder.h"
+#include "mark.h"
+#include "node.h"
+#include "nodeproperties.h"
+#include <cassert>
+
+namespace YAML
+{
+	NodeBuilder::NodeBuilder(Node& root): m_root(root), m_initializedRoot(false), m_finished(false)
+	{
+		m_root.Clear();
+		m_anchors.push_back(0); // since the anchors start at 1
+	}
+	
+	NodeBuilder::~NodeBuilder()
+	{
+	}
+
+	void NodeBuilder::OnDocumentStart(const Mark&)
+	{
+	}
+
+	void NodeBuilder::OnDocumentEnd()
+	{
+		assert(m_finished);
+	}
+
+	void NodeBuilder::OnNull(const std::string& tag, anchor_t anchor)
+	{
+		Node& node = Push(anchor);
+		node.InitNull(tag);
+		Pop();
+	}
+
+	void NodeBuilder::OnAlias(const Mark& mark, anchor_t anchor)
+	{
+		Node& node = Push();
+		node.InitAlias(mark, *m_anchors[anchor]);
+		Pop();
+	}
+
+	void NodeBuilder::OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value)
+	{
+		Node& node = Push(anchor);
+		node.Init(CT_SCALAR, mark, tag);
+		node.SetData(value);
+		Pop();
+	}
+
+	void NodeBuilder::OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+	{
+		Node& node = Push(anchor);
+		node.Init(CT_SEQUENCE, mark, tag);
+	}
+
+	void NodeBuilder::OnSequenceEnd()
+	{
+		Pop();
+	}
+
+	void NodeBuilder::OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor)
+	{
+		Node& node = Push(anchor);
+		node.Init(CT_MAP, mark, tag);
+		m_didPushKey.push(false);
+	}
+
+	void NodeBuilder::OnMapEnd()
+	{
+		m_didPushKey.pop();
+		Pop();
+	}
+	
+	Node& NodeBuilder::Push(anchor_t anchor)
+	{
+		Node& node = Push();
+		RegisterAnchor(anchor, node);
+		return node;
+	}
+	
+	Node& NodeBuilder::Push()
+	{
+		if(!m_initializedRoot) {
+			m_initializedRoot = true;
+			return m_root;
+		}
+		
+		std::auto_ptr<Node> pNode(new Node);
+		m_stack.push(pNode);
+		return m_stack.top();
+	}
+	
+	Node& NodeBuilder::Top()
+	{
+		return m_stack.empty() ? m_root : m_stack.top();
+	}
+	
+	void NodeBuilder::Pop()
+	{
+		assert(!m_finished);
+		if(m_stack.empty()) {
+			m_finished = true;
+			return;
+		}
+		
+		std::auto_ptr<Node> pNode = m_stack.pop();
+		Insert(pNode);
+	}
+	
+	void NodeBuilder::Insert(std::auto_ptr<Node> pNode)
+	{
+		Node& node = Top();
+		switch(node.GetType()) {
+			case CT_SEQUENCE:
+				node.Append(pNode);
+				break;
+			case CT_MAP:
+				assert(!m_didPushKey.empty());
+				if(m_didPushKey.top()) {
+					assert(!m_pendingKeys.empty());
+
+					std::auto_ptr<Node> pKey = m_pendingKeys.pop();
+					node.Insert(pKey, pNode);
+					m_didPushKey.top() = false;
+				} else {
+					m_pendingKeys.push(pNode);
+					m_didPushKey.top() = true;
+				}
+				break;
+			default:
+				assert(false);
+		}
+	}
+
+	void NodeBuilder::RegisterAnchor(anchor_t anchor, const Node& node)
+	{
+		if(anchor) {
+			assert(anchor == m_anchors.size());
+			m_anchors.push_back(&node);
+		}
+	}
+}

src/nodebuilder.h

@@ -0,0 +1,59 @@
+#pragma once
+
+#ifndef NODEBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define NODEBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include "eventhandler.h"
+#include "ptr_stack.h"
+#include <map>
+#include <memory>
+#include <stack>
+
+namespace YAML
+{
+	class Node;
+	
+	class NodeBuilder: public EventHandler
+	{
+	public:
+		explicit NodeBuilder(Node& root);
+		virtual ~NodeBuilder();
+
+		virtual void OnDocumentStart(const Mark& mark);
+		virtual void OnDocumentEnd();
+		
+		virtual void OnNull(const std::string& tag, anchor_t anchor);
+		virtual void OnAlias(const Mark& mark, anchor_t anchor);
+		virtual void OnScalar(const Mark& mark, const std::string& tag, anchor_t anchor, const std::string& value);
+		
+		virtual void OnSequenceStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+		virtual void OnSequenceEnd();
+		
+		virtual void OnMapStart(const Mark& mark, const std::string& tag, anchor_t anchor);
+		virtual void OnMapEnd();
+		
+	private:
+		Node& Push(anchor_t anchor);
+		Node& Push();
+		Node& Top();
+		void Pop();
+
+		void Insert(std::auto_ptr<Node> pNode);
+		void RegisterAnchor(anchor_t anchor, const Node& node);
+		
+	private:
+		Node& m_root;
+		bool m_initializedRoot;
+		bool m_finished;
+		
+		ptr_stack<Node> m_stack;
+		ptr_stack<Node> m_pendingKeys;
+		std::stack<bool> m_didPushKey;
+
+		typedef std::vector<const Node *> Anchors;
+		Anchors m_anchors;
+	};
+}
+
+#endif // NODEBUILDER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+

src/parser.cpp

@@ -1,8 +1,14 @@
 #include "parser.h"
-#include "scanner.h"
+#include "directives.h"
-#include "token.h"
+#include "eventhandler.h"
 #include "exceptions.h"
-#include "parserstate.h"
+#include "graphbuilderadapter.h"
+#include "node.h"
+#include "nodebuilder.h"
+#include "scanner.h"
+#include "singledocparser.h"
+#include "tag.h"
+#include "token.h"
 #include <sstream>
 #include <cstdio>
 
@@ -29,7 +35,38 @@ namespace YAML
 	void Parser::Load(std::istream& in)
 	{
 		m_pScanner.reset(new Scanner(in));
-		m_pState.reset(new ParserState);
+		m_pDirectives.reset(new Directives);
+	}
+
+	// HandleNextDocument
+	// . Handles the next document
+	// . Throws a ParserException on error.
+	// . Returns false if there are no more documents
+	bool Parser::HandleNextDocument(EventHandler& eventHandler)
+	{
+		if(!m_pScanner.get())
+			return false;
+
+		ParseDirectives();
+		if(m_pScanner->empty())
+			return false;
+		
+		SingleDocParser sdp(*m_pScanner, *m_pDirectives);
+		sdp.HandleDocument(eventHandler);
+		return true;
+	}
+	
+	// BuildNextDocumentGraph
+	// . Builds a graph of the next document
+	// . Returns NULL if there are no more documents
+	void *Parser::BuildNextDocumentGraph(GraphBuilderInterface& graphBuilder)
+	{
+		GraphBuilderAdapter eventHandler(graphBuilder);
+		if (HandleNextDocument(eventHandler)) {
+			return eventHandler.RootNode();
+		} else {
+			return NULL;
+		}
 	}
 
 	// GetNextDocument
@@ -37,34 +74,8 @@ namespace YAML
 	// . Throws a ParserException on error.
 	bool Parser::GetNextDocument(Node& document)
 	{
-		if(!m_pScanner.get())
+		NodeBuilder builder(document);
-			return false;
+		return HandleNextDocument(builder);
-		
-		// clear node
-		document.Clear();
-
-		// first read directives
-		ParseDirectives();
-
-		// we better have some tokens in the queue
-		if(m_pScanner->empty())
-			return false;
-
-		// first eat doc start (optional)
-		if(m_pScanner->peek().type == Token::DOC_START)
-			m_pScanner->pop();
-
-		// now parse our root node
-		document.Parse(m_pScanner.get(), *m_pState);
-
-		// and finally eat any doc ends we see
-		while(!m_pScanner->empty() && m_pScanner->peek().type == Token::DOC_END)
-			m_pScanner->pop();
-
-		// clear anchors from the scanner, which are no longer relevant
-		m_pScanner->ClearAnchors();
-		
-		return true;
 	}
 
 	// ParseDirectives
@@ -84,7 +95,7 @@ namespace YAML
 			// we keep the directives from the last document if none are specified;
 			// but if any directives are specific, then we reset them
 			if(!readDirective)
-				m_pState.reset(new ParserState);
+				m_pDirectives.reset(new Directives);
 
 			readDirective = true;
 			HandleDirective(token);
@@ -107,20 +118,20 @@ namespace YAML
 		if(token.params.size() != 1)
 			throw ParserException(token.mark, ErrorMsg::YAML_DIRECTIVE_ARGS);
 		
-		if(!m_pState->version.isDefault)
+		if(!m_pDirectives->version.isDefault)
 			throw ParserException(token.mark, ErrorMsg::REPEATED_YAML_DIRECTIVE);
 
 		std::stringstream str(token.params[0]);
-		str >> m_pState->version.major;
+		str >> m_pDirectives->version.major;
 		str.get();
-		str >> m_pState->version.minor;
+		str >> m_pDirectives->version.minor;
 		if(!str || str.peek() != EOF)
 			throw ParserException(token.mark, ErrorMsg::YAML_VERSION + token.params[0]);
 
-		if(m_pState->version.major > 1)
+		if(m_pDirectives->version.major > 1)
 			throw ParserException(token.mark, ErrorMsg::YAML_MAJOR_VERSION);
 
-		m_pState->version.isDefault = false;
+		m_pDirectives->version.isDefault = false;
 		// TODO: warning on major == 1, minor > 2?
 	}
 
@@ -133,10 +144,10 @@ namespace YAML
 
 		const std::string& handle = token.params[0];
 		const std::string& prefix = token.params[1];
-		if(m_pState->tags.find(handle) != m_pState->tags.end())
+		if(m_pDirectives->tags.find(handle) != m_pDirectives->tags.end())
 			throw ParserException(token.mark, ErrorMsg::REPEATED_TAG_DIRECTIVE);
 		
-		m_pState->tags[handle] = prefix;
+		m_pDirectives->tags[handle] = prefix;
 	}
 
 	void Parser::PrintTokens(std::ostream& out)

src/parserstate.h

@@ -1,37 +0,0 @@
-#pragma once
-
-#ifndef PARSERSTATE_H_62B23520_7C8E_11DE_8A39_0800200C9A66
-#define PARSERSTATE_H_62B23520_7C8E_11DE_8A39_0800200C9A66
-
-
-#include <string>
-#include <map>
-#include <stack>
-#include <cassert>
-
-namespace YAML
-{
-	struct Version {
-		bool isDefault;
-		int major, minor;
-	};
-	
-	struct ParserState
-	{
-		enum COLLECTION_TYPE { NONE, BLOCK_MAP, BLOCK_SEQ, FLOW_MAP, FLOW_SEQ, COMPACT_MAP };
-		
-		ParserState();
-
-		const std::string TranslateTagHandle(const std::string& handle) const;
-		COLLECTION_TYPE GetCurCollectionType() const { if(collectionStack.empty()) return NONE; return collectionStack.top(); }
-		
-		void PushCollectionType(COLLECTION_TYPE type) { collectionStack.push(type); }
-		void PopCollectionType(COLLECTION_TYPE type) { assert(type == GetCurCollectionType()); collectionStack.pop(); }
-	
-		Version version;
-		std::map <std::string, std::string> tags;
-		std::stack <COLLECTION_TYPE> collectionStack;
-	};
-}
-
-#endif // PARSERSTATE_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/ptr_stack.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#ifndef PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+#include <memory>
+#include <vector>
+
+template <typename T>
+class ptr_stack
+{
+public:
+	ptr_stack() {}
+	~ptr_stack() { clear(); }
+	
+	void clear() {
+		for(unsigned i=0;i<m_data.size();i++)
+			delete m_data[i];
+		m_data.clear();
+	}
+	
+	std::size_t size() const { return m_data.size(); }
+	bool empty() const { return m_data.empty(); }
+	
+	void push(std::auto_ptr<T> t) { m_data.push_back(t.release()); }
+	std::auto_ptr<T> pop() {
+		std::auto_ptr<T> t(m_data.back());
+		m_data.pop_back();
+		return t;
+	}
+	T& top() { return *m_data.back(); }
+	
+private:
+	std::vector<T*> m_data;
+};
+
+#endif // PTR_STACK_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/scalar.cpp

@@ -1,9 +1,5 @@
 #include "scalar.h"
-#include "scanner.h"
+#include "eventhandler.h"
-#include "token.h"
-#include "exceptions.h"
-#include "node.h"
-#include "emitter.h"
 
 namespace YAML
 {
@@ -11,29 +7,13 @@ namespace YAML
 	{
 	}
 
-	Scalar::Scalar(const std::string& data): m_data(data)
-	{
-	}
-
 	Scalar::~Scalar()
 	{
 	}
 
-	Content *Scalar::Clone() const
+	void Scalar::EmitEvents(AliasManager&, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const
 	{
-		return new Scalar(m_data);
+		eventHandler.OnScalar(mark, tag, anchor, m_data);
-	}
-
-	void Scalar::Parse(Scanner *pScanner, ParserState& /*state*/)
-	{
-		Token& token = pScanner->peek();
-		m_data = token.value;
-		pScanner->pop();
-	}
-
-	void Scalar::Write(Emitter& out) const
-	{
-		out << m_data;
 	}
 
 	int Scalar::Compare(Content *pContent)

src/scalar.h

@@ -13,15 +13,12 @@ namespace YAML
 	{
 	public:
 		Scalar();
-		Scalar(const std::string& data);
 		virtual ~Scalar();
 
-		virtual Content *Clone() const;
+		virtual void SetData(const std::string& data) { m_data = data; }
-
-		virtual void Parse(Scanner *pScanner, ParserState& state);
-		virtual void Write(Emitter& out) const;
 
 		virtual bool IsScalar() const { return true; }
+		virtual void EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const;
 
 		// extraction
 		virtual bool GetScalar(std::string& scalar) const {

src/scanner.cpp

@@ -32,14 +32,9 @@ namespace YAML
 	void Scanner::pop()
 	{
 		EnsureTokensInQueue();
-		if(!m_tokens.empty()) {
+		if(!m_tokens.empty())
-			// Saved anchors shouldn't survive popping the document end marker
-			if (m_tokens.front().type == Token::DOC_END) {
-				ClearAnchors();
-			}
 			m_tokens.pop();
 	}
-	}
 
 	// peek
 	// . Returns (but does not remove) the next token on the queue.
@@ -245,7 +240,6 @@ namespace YAML
 		IndentMarker *pIndent = new IndentMarker(-1, IndentMarker::NONE);
 		m_indentRefs.push_back(pIndent);
 		m_indents.push(pIndent);
-		m_anchors.clear();
 	}
 
 	// EndStream
@@ -378,29 +372,6 @@ namespace YAML
 		return m_indents.top()->column;
 	}
 
-	// Save
-	// . Saves a pointer to the Node object referenced by a particular anchor
-	//   name.
-	void Scanner::Save(const std::string& anchor, Node* value)
-	{
-		m_anchors[anchor] = value;
-	}
-
-	// Retrieve
-	// . Retrieves a pointer previously saved for an anchor name.
-	// . Throws an exception if the anchor has not been defined.
-	const Node *Scanner::Retrieve(const std::string& anchor) const
-	{
-		typedef std::map<std::string, const Node *> map;
-
-		map::const_iterator itNode = m_anchors.find(anchor);
-
-		if(m_anchors.end() == itNode)
-			ThrowParserException(ErrorMsg::UNKNOWN_ANCHOR);
-
-		return itNode->second;
-	}
-
 	// ThrowParserException
 	// . Throws a ParserException with the current token location
 	//   (if available).
@@ -414,10 +385,5 @@ namespace YAML
 		}
 		throw ParserException(mark, msg);
 	}
-
-	void Scanner::ClearAnchors()
-	{
-		m_anchors.clear();
-	}
 }
 

src/scanner.h

@@ -29,11 +29,6 @@ namespace YAML
 		void pop();
 		Token& peek();
 
-		// anchor management
-		void Save(const std::string& anchor, Node* value);
-		const Node *Retrieve(const std::string& anchor) const;
-		void ClearAnchors();
-
 	private:
 		struct IndentMarker {
 			enum INDENT_TYPE { MAP, SEQ, NONE };
@@ -127,7 +122,6 @@ namespace YAML
 		std::stack <IndentMarker *> m_indents;
 		std::vector <IndentMarker *> m_indentRefs; // for "garbage collection"
 		std::stack <FLOW_MARKER> m_flows;
-		std::map <std::string, const Node *> m_anchors;
 	};
 }
 

src/sequence.cpp

@@ -1,8 +1,6 @@
 #include "sequence.h"
+#include "eventhandler.h"
 #include "node.h"
-#include "scanner.h"
-#include "token.h"
-#include "emitter.h"
 #include <stdexcept>
 
 namespace YAML
@@ -12,12 +10,6 @@ namespace YAML
 
 	}
 
-	Sequence::Sequence(const std::vector<Node *>& data)
-	{
-		for(std::size_t i=0;i<data.size();i++)
-			m_data.push_back(data[i]->Clone().release());
-	}
-
 	Sequence::~Sequence()
 	{
 		Clear();
@@ -30,11 +22,6 @@ namespace YAML
 		m_data.clear();
 	}
 
-	Content *Sequence::Clone() const
-	{
-		return new Sequence(m_data);
-	}
-
 	bool Sequence::GetBegin(std::vector <Node *>::const_iterator& it) const
 	{
 		it = m_data.begin();
@@ -59,90 +46,17 @@ namespace YAML
 		return m_data.size();
 	}
 
-	void Sequence::Parse(Scanner *pScanner, ParserState& state)
+	void Sequence::Append(std::auto_ptr<Node> pNode)
 	{
-		Clear();
+		m_data.push_back(pNode.release());
-
-		// split based on start token
-		switch(pScanner->peek().type) {
-			case Token::BLOCK_SEQ_START: ParseBlock(pScanner, state); break;
-			case Token::FLOW_SEQ_START: ParseFlow(pScanner, state); break;
-			default: break;
-		}
 	}
 	
-	void Sequence::ParseBlock(Scanner *pScanner, ParserState& state)
+	void Sequence::EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const
 	{
-		// eat start token
+		eventHandler.OnSequenceStart(mark, tag, anchor);
-		pScanner->pop();
-		state.PushCollectionType(ParserState::BLOCK_SEQ);
-
-		while(1) {
-			if(pScanner->empty())
-				throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ);
-
-			Token token = pScanner->peek();
-			if(token.type != Token::BLOCK_ENTRY && token.type != Token::BLOCK_SEQ_END)
-				throw ParserException(token.mark, ErrorMsg::END_OF_SEQ);
-
-			pScanner->pop();
-			if(token.type == Token::BLOCK_SEQ_END)
-				break;
-
-			Node *pNode = new Node;
-			m_data.push_back(pNode);
-			
-			// check for null
-			if(!pScanner->empty()) {
-				const Token& token = pScanner->peek();
-				if(token.type == Token::BLOCK_ENTRY || token.type == Token::BLOCK_SEQ_END)
-					continue;
-			}
-			
-			pNode->Parse(pScanner, state);
-		}
-
-		state.PopCollectionType(ParserState::BLOCK_SEQ);
-	}
-
-	void Sequence::ParseFlow(Scanner *pScanner, ParserState& state)
-	{
-		// eat start token
-		pScanner->pop();
-		state.PushCollectionType(ParserState::FLOW_SEQ);
-
-		while(1) {
-			if(pScanner->empty())
-				throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ_FLOW);
-
-			// first check for end
-			if(pScanner->peek().type == Token::FLOW_SEQ_END) {
-				pScanner->pop();
-				break;
-			}
-
-			// then read the node
-			Node *pNode = new Node;
-			m_data.push_back(pNode);
-			pNode->Parse(pScanner, state);
-
-			// now eat the separator (or could be a sequence end, which we ignore - but if it's neither, then it's a bad node)
-			Token& token = pScanner->peek();
-			if(token.type == Token::FLOW_ENTRY)
-				pScanner->pop();
-			else if(token.type != Token::FLOW_SEQ_END)
-				throw ParserException(token.mark, ErrorMsg::END_OF_SEQ_FLOW);
-		}
-
-		state.PopCollectionType(ParserState::FLOW_SEQ);
-	}
-
-	void Sequence::Write(Emitter& out) const
-	{
-		out << BeginSeq;
 		for(std::size_t i=0;i<m_data.size();i++)
-			out << *m_data[i];
+			m_data[i]->EmitEvents(am, eventHandler);
-		out << EndSeq;
+		eventHandler.OnSequenceEnd();
 	}
 
 	int Sequence::Compare(Content *pContent)

src/sequence.h

@@ -15,19 +15,17 @@ namespace YAML
 	{
 	public:
 		Sequence();
-		Sequence(const std::vector<Node *>& data);
 		virtual ~Sequence();
 
 		void Clear();
-		virtual Content *Clone() const;
 
 		virtual bool GetBegin(std::vector <Node *>::const_iterator& it) const;
 		virtual bool GetEnd(std::vector <Node *>::const_iterator& it) const;
 		virtual Node *GetNode(std::size_t i) const;
 		virtual std::size_t GetSize() const;
 
-		virtual void Parse(Scanner *pScanner, ParserState& state);
+		virtual void Append(std::auto_ptr<Node> pNode);
-		virtual void Write(Emitter& out) const;
+		virtual void EmitEvents(AliasManager& am, EventHandler& eventHandler, const Mark& mark, const std::string& tag, anchor_t anchor) const;
 
 		virtual bool IsSequence() const { return true; }
 
@@ -37,10 +35,6 @@ namespace YAML
 		virtual int Compare(Sequence *pSeq);
 		virtual int Compare(Map *) { return -1; }
 
-	private:
-		void ParseBlock(Scanner *pScanner, ParserState& state);
-		void ParseFlow(Scanner *pScanner, ParserState& state);
-
 	protected:
 		std::vector <Node *> m_data;
 	};

src/singledocparser.cpp

@@ -0,0 +1,369 @@
+#include "singledocparser.h"
+#include "collectionstack.h"
+#include "directives.h"
+#include "eventhandler.h"
+#include "exceptions.h"
+#include "scanner.h"
+#include "tag.h"
+#include "token.h"
+#include <sstream>
+#include <cstdio>
+
+namespace YAML
+{
+	SingleDocParser::SingleDocParser(Scanner& scanner, const Directives& directives): m_scanner(scanner), m_directives(directives), m_pCollectionStack(new CollectionStack), m_curAnchor(0)
+	{
+	}
+
+	SingleDocParser::~SingleDocParser()
+	{
+	}
+
+	// HandleDocument
+	// . Handles the next document
+	// . Throws a ParserException on error.
+	void SingleDocParser::HandleDocument(EventHandler& eventHandler)
+	{
+		assert(!m_scanner.empty()); // guaranteed that there are tokens
+		assert(!m_curAnchor);
+
+		eventHandler.OnDocumentStart(m_scanner.peek().mark);
+		
+		// eat doc start
+		if(m_scanner.peek().type == Token::DOC_START)
+			m_scanner.pop();
+		
+		// recurse!
+		HandleNode(eventHandler);
+		
+		eventHandler.OnDocumentEnd();
+		
+		// and finally eat any doc ends we see
+		while(!m_scanner.empty() && m_scanner.peek().type == Token::DOC_END)
+			m_scanner.pop();
+	}
+	
+	void SingleDocParser::HandleNode(EventHandler& eventHandler)
+	{
+		// an empty node *is* a possibility
+		if(m_scanner.empty()) {
+			eventHandler.OnNull("", NullAnchor);
+			return;
+		}
+		
+		// save location
+		Mark mark = m_scanner.peek().mark;
+		
+		// special case: a value node by itself must be a map, with no header
+		if(m_scanner.peek().type == Token::VALUE) {
+			eventHandler.OnMapStart(mark, "", NullAnchor);
+			HandleMap(eventHandler);
+			eventHandler.OnMapEnd();
+			return;
+		}
+		
+		// special case: an alias node
+		if(m_scanner.peek().type == Token::ALIAS) {
+			eventHandler.OnAlias(mark, LookupAnchor(mark, m_scanner.peek().value));
+			m_scanner.pop();
+			return;
+		}
+		
+		std::string tag;
+		anchor_t anchor;
+		ParseProperties(tag, anchor);
+		
+		// now split based on what kind of node we should be
+		switch(m_scanner.peek().type) {
+			case Token::SCALAR:
+				eventHandler.OnScalar(mark, tag, anchor, m_scanner.peek().value);
+				m_scanner.pop();
+				return;
+			case Token::FLOW_SEQ_START:
+			case Token::BLOCK_SEQ_START:
+				eventHandler.OnSequenceStart(mark, tag, anchor);
+				HandleSequence(eventHandler);
+				eventHandler.OnSequenceEnd();
+				return;
+			case Token::FLOW_MAP_START:
+			case Token::BLOCK_MAP_START:
+				eventHandler.OnMapStart(mark, tag, anchor);
+				HandleMap(eventHandler);
+				eventHandler.OnMapEnd();
+				return;
+			case Token::KEY:
+				// compact maps can only go in a flow sequence
+				if(m_pCollectionStack->GetCurCollectionType() == CollectionType::FlowSeq) {
+					eventHandler.OnMapStart(mark, tag, anchor);
+					HandleMap(eventHandler);
+					eventHandler.OnMapEnd();
+					return;
+				}
+				break;
+			default:
+				break;
+		}
+		
+		eventHandler.OnNull(tag, anchor);
+	}
+	
+	void SingleDocParser::HandleSequence(EventHandler& eventHandler)
+	{
+		// split based on start token
+		switch(m_scanner.peek().type) {
+			case Token::BLOCK_SEQ_START: HandleBlockSequence(eventHandler); break;
+			case Token::FLOW_SEQ_START: HandleFlowSequence(eventHandler); break;
+			default: break;
+		}
+	}
+	
+	void SingleDocParser::HandleBlockSequence(EventHandler& eventHandler)
+	{
+		// eat start token
+		m_scanner.pop();
+		m_pCollectionStack->PushCollectionType(CollectionType::BlockSeq);
+		
+		while(1) {
+			if(m_scanner.empty())
+				throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ);
+			
+			Token token = m_scanner.peek();
+			if(token.type != Token::BLOCK_ENTRY && token.type != Token::BLOCK_SEQ_END)
+				throw ParserException(token.mark, ErrorMsg::END_OF_SEQ);
+			
+			m_scanner.pop();
+			if(token.type == Token::BLOCK_SEQ_END)
+				break;
+			
+			// check for null
+			if(!m_scanner.empty()) {
+				const Token& token = m_scanner.peek();
+				if(token.type == Token::BLOCK_ENTRY || token.type == Token::BLOCK_SEQ_END) {
+					eventHandler.OnNull("", NullAnchor);
+					continue;
+				}
+			}
+			
+			HandleNode(eventHandler);
+		}
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::BlockSeq);
+	}
+	
+	void SingleDocParser::HandleFlowSequence(EventHandler& eventHandler)
+	{
+		// eat start token
+		m_scanner.pop();
+		m_pCollectionStack->PushCollectionType(CollectionType::FlowSeq);
+		
+		while(1) {
+			if(m_scanner.empty())
+				throw ParserException(Mark::null(), ErrorMsg::END_OF_SEQ_FLOW);
+			
+			// first check for end
+			if(m_scanner.peek().type == Token::FLOW_SEQ_END) {
+				m_scanner.pop();
+				break;
+			}
+			
+			// then read the node
+			HandleNode(eventHandler);
+			
+			// now eat the separator (or could be a sequence end, which we ignore - but if it's neither, then it's a bad node)
+			Token& token = m_scanner.peek();
+			if(token.type == Token::FLOW_ENTRY)
+				m_scanner.pop();
+			else if(token.type != Token::FLOW_SEQ_END)
+				throw ParserException(token.mark, ErrorMsg::END_OF_SEQ_FLOW);
+		}
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::FlowSeq);
+	}
+	
+	void SingleDocParser::HandleMap(EventHandler& eventHandler)
+	{
+		// split based on start token
+		switch(m_scanner.peek().type) {
+			case Token::BLOCK_MAP_START: HandleBlockMap(eventHandler); break;
+			case Token::FLOW_MAP_START: HandleFlowMap(eventHandler); break;
+			case Token::KEY: HandleCompactMap(eventHandler); break;
+			case Token::VALUE: HandleCompactMapWithNoKey(eventHandler); break;
+			default: break;
+		}
+	}
+	
+	void SingleDocParser::HandleBlockMap(EventHandler& eventHandler)
+	{
+		// eat start token
+		m_scanner.pop();
+		m_pCollectionStack->PushCollectionType(CollectionType::BlockMap);
+		
+		while(1) {
+			if(m_scanner.empty())
+				throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP);
+			
+			Token token = m_scanner.peek();
+			if(token.type != Token::KEY && token.type != Token::VALUE && token.type != Token::BLOCK_MAP_END)
+				throw ParserException(token.mark, ErrorMsg::END_OF_MAP);
+			
+			if(token.type == Token::BLOCK_MAP_END) {
+				m_scanner.pop();
+				break;
+			}
+			
+			// grab key (if non-null)
+			if(token.type == Token::KEY) {
+				m_scanner.pop();
+				HandleNode(eventHandler);
+			} else {
+				eventHandler.OnNull("", NullAnchor);
+			}
+			
+			// now grab value (optional)
+			if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
+				m_scanner.pop();
+				HandleNode(eventHandler);
+			} else {
+				eventHandler.OnNull("", NullAnchor);
+			}
+		}
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::BlockMap);
+	}
+	
+	void SingleDocParser::HandleFlowMap(EventHandler& eventHandler)
+	{
+		// eat start token
+		m_scanner.pop();
+		m_pCollectionStack->PushCollectionType(CollectionType::FlowMap);
+		
+		while(1) {
+			if(m_scanner.empty())
+				throw ParserException(Mark::null(), ErrorMsg::END_OF_MAP_FLOW);
+			
+			Token& token = m_scanner.peek();
+			// first check for end
+			if(token.type == Token::FLOW_MAP_END) {
+				m_scanner.pop();
+				break;
+			}
+			
+			// grab key (if non-null)
+			if(token.type == Token::KEY) {
+				m_scanner.pop();
+				HandleNode(eventHandler);
+			} else {
+				eventHandler.OnNull("", NullAnchor);
+			}
+			
+			// now grab value (optional)
+			if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
+				m_scanner.pop();
+				HandleNode(eventHandler);
+			} else {
+				eventHandler.OnNull("", NullAnchor);
+			}
+			
+			// now eat the separator (or could be a map end, which we ignore - but if it's neither, then it's a bad node)
+			Token& nextToken = m_scanner.peek();
+			if(nextToken.type == Token::FLOW_ENTRY)
+				m_scanner.pop();
+			else if(nextToken.type != Token::FLOW_MAP_END)
+				throw ParserException(nextToken.mark, ErrorMsg::END_OF_MAP_FLOW);
+		}
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::FlowMap);
+	}
+	
+	// . Single "key: value" pair in a flow sequence
+	void SingleDocParser::HandleCompactMap(EventHandler& eventHandler)
+	{
+		m_pCollectionStack->PushCollectionType(CollectionType::CompactMap);
+		
+		// grab key
+		m_scanner.pop();
+		HandleNode(eventHandler);
+		
+		// now grab value (optional)
+		if(!m_scanner.empty() && m_scanner.peek().type == Token::VALUE) {
+			m_scanner.pop();
+			HandleNode(eventHandler);
+		} else {
+			eventHandler.OnNull("", NullAnchor);
+		}
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::CompactMap);
+	}
+	
+	// . Single ": value" pair in a flow sequence
+	void SingleDocParser::HandleCompactMapWithNoKey(EventHandler& eventHandler)
+	{
+		m_pCollectionStack->PushCollectionType(CollectionType::CompactMap);
+		
+		// null key
+		eventHandler.OnNull("", NullAnchor);
+		
+		// grab value
+		m_scanner.pop();
+		HandleNode(eventHandler);
+		
+		m_pCollectionStack->PopCollectionType(CollectionType::CompactMap);
+	}
+	
+	// ParseProperties
+	// . Grabs any tag or anchor tokens and deals with them.
+	void SingleDocParser::ParseProperties(std::string& tag, anchor_t& anchor)
+	{
+		tag.clear();
+		anchor = NullAnchor;
+		
+		while(1) {
+			if(m_scanner.empty())
+				return;
+			
+			switch(m_scanner.peek().type) {
+				case Token::TAG: ParseTag(tag); break;
+				case Token::ANCHOR: ParseAnchor(anchor); break;
+				default: return;
+			}
+		}
+	}
+	
+	void SingleDocParser::ParseTag(std::string& tag)
+	{
+		Token& token = m_scanner.peek();
+		if(!tag.empty())
+			throw ParserException(token.mark, ErrorMsg::MULTIPLE_TAGS);
+		
+		Tag tagInfo(token);
+		tag = tagInfo.Translate(m_directives);
+		m_scanner.pop();
+	}
+	
+	void SingleDocParser::ParseAnchor(anchor_t& anchor)
+	{
+		Token& token = m_scanner.peek();
+		if(anchor)
+			throw ParserException(token.mark, ErrorMsg::MULTIPLE_ANCHORS);
+		
+		anchor = RegisterAnchor(token.value);
+		m_scanner.pop();
+	}
+	
+	anchor_t SingleDocParser::RegisterAnchor(const std::string& name)
+	{
+		if(name.empty())
+			return NullAnchor;
+		
+		return m_anchors[name] = ++m_curAnchor;
+	}
+	
+	anchor_t SingleDocParser::LookupAnchor(const Mark& mark, const std::string& name) const
+	{
+		Anchors::const_iterator it = m_anchors.find(name);
+		if(it == m_anchors.end())
+			throw ParserException(mark, ErrorMsg::UNKNOWN_ANCHOR);
+		
+		return it->second;
+	}
+}

src/singledocparser.h

@@ -0,0 +1,63 @@
+#pragma once
+
+#ifndef SINGLEDOCPARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+#define SINGLEDOCPARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66
+
+
+#include "anchor.h"
+#include "noncopyable.h"
+#include <string>
+#include <map>
+#include <memory>
+
+namespace YAML
+{
+	struct Directives;
+	struct Mark;
+	struct Token;
+	class CollectionStack;
+	class EventHandler;
+	class Node;
+	class Scanner;
+	
+	class SingleDocParser: private noncopyable
+	{
+	public:
+		SingleDocParser(Scanner& scanner, const Directives& directives);
+		~SingleDocParser();
+
+		void HandleDocument(EventHandler& eventHandler);
+
+	private:
+		void HandleNode(EventHandler& eventHandler);
+		
+		void HandleSequence(EventHandler& eventHandler);
+		void HandleBlockSequence(EventHandler& eventHandler);
+		void HandleFlowSequence(EventHandler& eventHandler);
+		
+		void HandleMap(EventHandler& eventHandler);
+		void HandleBlockMap(EventHandler& eventHandler);
+		void HandleFlowMap(EventHandler& eventHandler);
+		void HandleCompactMap(EventHandler& eventHandler);
+		void HandleCompactMapWithNoKey(EventHandler& eventHandler);
+		
+		void ParseProperties(std::string& tag, anchor_t& anchor);
+		void ParseTag(std::string& tag);
+		void ParseAnchor(anchor_t& anchor);
+		
+		anchor_t RegisterAnchor(const std::string& name);
+		anchor_t LookupAnchor(const Mark& mark, const std::string& name) const;
+		
+	private:
+		Scanner& m_scanner;
+		const Directives& m_directives;
+		std::auto_ptr<CollectionStack> m_pCollectionStack;
+		
+		typedef std::map<std::string, anchor_t> Anchors;
+		Anchors m_anchors;
+		
+		anchor_t m_curAnchor;
+	};
+}
+
+#endif // SINGLEDOCPARSER_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/tag.cpp

@@ -1,6 +1,6 @@
 #include "tag.h"
+#include "directives.h"
 #include "token.h"
-#include "parserstate.h"
 #include <cassert>
 
 namespace YAML
@@ -28,17 +28,17 @@ namespace YAML
 		}
 	}
 
-	const std::string Tag::Translate(const ParserState& state)
+	const std::string Tag::Translate(const Directives& directives)
 	{
 		switch(type) {
 			case VERBATIM:
 				return value;
 			case PRIMARY_HANDLE:
-				return state.TranslateTagHandle("!") + value;
+				return directives.TranslateTagHandle("!") + value;
 			case SECONDARY_HANDLE:
-				return state.TranslateTagHandle("!!") + value;
+				return directives.TranslateTagHandle("!!") + value;
 			case NAMED_HANDLE:
-				return state.TranslateTagHandle("!" + handle + "!") + value;
+				return directives.TranslateTagHandle("!" + handle + "!") + value;
 			case NON_SPECIFIC:
 				// TODO:
 				return "!";

src/tag.h

@@ -8,7 +8,7 @@
 namespace YAML
 {
 	struct Token;
-	struct ParserState;
+	struct Directives;
 
 	struct Tag {
 		enum TYPE {
@@ -16,7 +16,7 @@ namespace YAML
 		};
 		
 		Tag(const Token& token);
-		const std::string Translate(const ParserState& state);
+		const std::string Translate(const Directives& directives);
 		
 		TYPE type;
 		std::string handle, value;

util/parse.cpp

@@ -1,9 +1,25 @@
 #include "yaml.h"
 #include <fstream>
 #include <iostream>
+#include <vector>
+
+struct Params {
+	bool hasFile;
+	std::string fileName;
+};
+
+Params ParseArgs(int argc, char **argv) {
+	Params p;
+
+	std::vector<char*> args(argv + 1, argv + argc);
+	
+	return p;
+}
 
 int main(int argc, char **argv)
 {
+	Params p = ParseArgs(argc, argv);
+
 	std::ifstream fin;
 	if(argc > 1)
 		fin.open(argv[1]);