exceptions.h

@@ -18,6 +18,8 @@ namespace YAML
 	class RequiredSimpleKeyNotFound: public Exception {};
 	class ZeroIndentationInBlockScalar: public Exception {};
 	class UnexpectedCharacterInBlockScalar: public Exception {};
+	class AnchorNotFound: public Exception {};
+	class IllegalCharacterInAnchor: public Exception {};
 
 	class UnknownEscapeSequence: public Exception {
 	public:

exp.h

@@ -16,6 +16,8 @@ namespace YAML
 		const RegEx Break = RegEx('\n');
 		const RegEx BlankOrBreak = Blank || Break;
 		const RegEx Digit = RegEx('0', '9');
+		const RegEx Alpha = RegEx('a', 'z') || RegEx('A', 'Z');
+		const RegEx AlphaNumeric = Alpha || Digit;
 		const RegEx Hex = Digit || RegEx('A', 'F') || RegEx('a', 'f');
 
 		// actual tags
@@ -28,6 +30,7 @@ namespace YAML
 		const RegEx Value = RegEx(':'),
 		            ValueInFlow = RegEx(':') + BlankOrBreak;
 		const RegEx Comment = RegEx('#');
+		const RegEx AnchorEnd = RegEx("?:,]}%@`", REGEX_OR) || BlankOrBreak;
 
 		// Plain scalar rules:
 		// . Cannot start with a blank.

scanner.cpp

@@ -148,9 +148,9 @@ namespace YAML
 		m_limboTokens.erase(pToken);
 	}
 
-	///////////////////////////////////////////////////////////////////////
-	// The main scanning function
-
+	// ScanNextToken
+	// . The main scanning function; here we branch out and
+	//   scan whatever the next token should be.
 	void Scanner::ScanNextToken()
 	{
 		if(m_endedStream)
@@ -159,21 +159,31 @@ namespace YAML
 		if(!m_startedStream)
 			return ScanAndEnqueue(new StreamStartToken);
 
+		// get rid of whitespace, etc. (in between tokens it should be irrelevent)
 		ScanToNextToken();
+
+		// check the latest simple key
 		ValidateSimpleKey();
+
+		// maybe need to end some blocks
 		PopIndentTo(m_column);
 
+		// *****
+		// And now branch based on the next few characters!
+		// *****
+
+		// end of stream
 		if(INPUT.peek() == EOF)
 			return ScanAndEnqueue(new StreamEndToken);
 
-		// are we at a document token?
+		// document token
 		if(IsDocumentStart())
 			return ScanAndEnqueue(new DocumentStartToken);
 
 		if(IsDocumentEnd())
 			return ScanAndEnqueue(new DocumentEndToken);
 
-		// are we at a flow start/end/entry?
+		// flow start/end/entry
 		if(INPUT.peek() == Keys::FlowSeqStart)
 			return ScanAndEnqueue(new FlowSeqStartToken);
 
@@ -189,7 +199,7 @@ namespace YAML
 		if(INPUT.peek() == Keys::FlowEntry)
 			return ScanAndEnqueue(new FlowEntryToken);
 
-		// block/map stuff?
+		// block/map stuff
 		if(IsBlockEntry())
 			return ScanAndEnqueue(new BlockEntryToken);
 
@@ -199,7 +209,10 @@ namespace YAML
 		if(IsValue())
 			return ScanAndEnqueue(new ValueToken);
 
-		// TODO: alias/anchor/tag
+		if(INPUT.peek() == Keys::Alias || INPUT.peek() == Keys::Anchor)
+			return ScanAndEnqueue(new AnchorToken);
+
+		// TODO: tag
 
 		// special scalars
 		if(m_flowLevel == 0 && (INPUT.peek() == Keys::LiteralScalar || INPUT.peek() == Keys::FoldedScalar))

scantoken.cpp

@@ -191,6 +191,36 @@ namespace YAML
 		return pToken;
 	}
 
+	// AnchorToken
+	template <> AnchorToken *Scanner::ScanToken(AnchorToken *pToken)
+	{
+		// insert a potential simple key
+		if(m_simpleKeyAllowed)
+			InsertSimpleKey();
+		m_simpleKeyAllowed = false;
+
+		// eat the indicator
+		char indicator = GetChar();
+		pToken->alias = (indicator == Keys::Alias);
+
+		// now eat the content
+		std::string tag;
+		while(Exp::AlphaNumeric.Matches(INPUT))
+			tag += GetChar();
+
+		// we need to have read SOMETHING!
+		if(tag.empty())
+			throw AnchorNotFound();
+
+		// and needs to end correctly
+		if(INPUT.peek() != EOF && !Exp::AnchorEnd.Matches(INPUT))
+			throw IllegalCharacterInAnchor();
+
+		// and we're done
+		pToken->value = tag;
+		return pToken;
+	}
+
 	// PlainScalarToken
 	// . We scan these in passes of two steps each: First, grab all non-whitespace
 	//   characters we can, and then grab all whitespace characters we can.

test.yaml

@@ -1,97 +1,13 @@
----
-model:
-    file: data/models/compound.model
-    textures: data/materials/compound
-rooms:
-    - name: "Room #1"
-      pos: [0, 0, 0]
-      size: [1000, 1000, 500]
-      height: 500
-      stairtype: none
-      display: []
-      pathfinding:
-          tilesize: 50
-          size: [24, 24]
-          map: |
-              -----------------------
-              -+++++++++++++++++++++-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+---------------------
-              -+---------------------
-              -+---------------------
-              -+---------------------
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+++++++++++++++++++++-
-              -----------------------
-    - name: Doorway
-      pos: [1000, 400, 0]
-      size: [50, 200, 500]
-      height: 500
-      stairtype: none
-      display: []
-      pathfinding:
-          tilesize: 50
-          size: [5, 9]
-          map: |
-              -----
-              -+++-
-              -----
-              -----
-              -----
-              -----
-              -----
-              -+++-
-              -----
-    - name: "Room #2"
-      pos: [1050, 0, 0]
-      size: [1000, 1000, 500]
-      height: 500
-      stairtype: none
-      display: []
-      pathfinding:
-          tilesize: 50
-          size: [24, 24]
-          map: |
-              -----------------------
-              -+++++++++++++++++++++-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              ---------------------+-
-              ---------------------+-
-              ---------------------+-
-              ---------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+-------------------+-
-              -+++++++++++++++++++++-
-              -----------------------
-exits:
-    - room1: "Room #1"
-      room2: "Room #2"
-      dir: e
-      pos: [400, 600]
+people:
+  - &jsb
+    name: Jesse
+    age: 23
+  - &dab
+    name: Daniel
+    age: 25
+  - &ncb
+    name: Naftali
+    age: 21
+students:
+  - *jsb
+  - *ncb

token.h

@@ -31,6 +31,12 @@ namespace YAML
 
 	struct KeyToken: public Token {};
 	struct ValueToken: public Token {};
+	struct AnchorToken: public Token {
+		bool alias;
+		std::string value;
+
+		virtual void Write(std::ostream& out) const { out << (alias ? '*' : '&') << value; }
+	};
 
 	struct ScalarToken: public Token {
 		std::string value;