diff --git a/tool/resources/org/antlr/v4/tool/templates/messages/languages/en.stg b/tool/resources/org/antlr/v4/tool/templates/messages/languages/en.stg
index d64477190..37988eb22 100644
--- a/tool/resources/org/antlr/v4/tool/templates/messages/languages/en.stg
+++ b/tool/resources/org/antlr/v4/tool/templates/messages/languages/en.stg
@@ -85,6 +85,8 @@ CANNOT_CREATE_TARGET_GENERATOR(arg,exception,stackTrace) ::=
 	"cannot create target <arg> code generator: <exception>"
 CANNOT_COMPUTE_SAMPLE_INPUT_SEQ() ::=
 	"cannot generate a sample input sequence from lookahead DFA"
+CODE_TEMPLATE_ARG_ISSUE(arg,arg2) ::=
+    "code generation template <arg> has missing, misnamed, or incomplete arg list: <arg2>"
 
 // grammar interpretation errors
 /*
diff --git a/tool/src/org/antlr/v4/codegen/CodeGenPipeline.java b/tool/src/org/antlr/v4/codegen/CodeGenPipeline.java
index 803536cd4..69c13531d 100644
--- a/tool/src/org/antlr/v4/codegen/CodeGenPipeline.java
+++ b/tool/src/org/antlr/v4/codegen/CodeGenPipeline.java
@@ -13,6 +13,12 @@ public class CodeGenPipeline {
 	}
 	public void process() {
 		if ( g.isLexer() ) processLexer();
+		else if ( g.isParser() ) processParser();
+	}
+
+	void processParser() {
+		ParserGenerator gen = new ParserGenerator(g);
+		gen.write();
 	}
 
 	void processLexer() {
diff --git a/tool/src/org/antlr/v4/codegen/CodeGenerator.java b/tool/src/org/antlr/v4/codegen/CodeGenerator.java
new file mode 100644
index 000000000..7109e7c45
--- /dev/null
+++ b/tool/src/org/antlr/v4/codegen/CodeGenerator.java
@@ -0,0 +1,125 @@
+package org.antlr.v4.codegen;
+
+import org.antlr.v4.codegen.src.OutputModelObject;
+import org.antlr.v4.tool.ErrorType;
+import org.antlr.v4.tool.Grammar;
+import org.stringtemplate.v4.*;
+
+import java.io.IOException;
+import java.io.Writer;
+
+/** */
+public abstract class CodeGenerator {
+	public static final String TEMPLATE_ROOT = "org/antlr/v4/tool/templates/codegen";
+	public static final String VOCAB_FILE_EXTENSION = ".tokens";
+	protected final static String vocabFilePattern =
+		"<tokens:{<attr.name>=<attr.type>\n}>" +
+		"<literals:{<attr.name>=<attr.type>\n}>";
+
+	Grammar g;
+	Target target;
+	STGroup templates;
+
+	int lineWidth = 72;
+
+	public CodeGenerator(Grammar g) {
+		this.g = g;
+		String language = g.getOption("language", "Java");
+		loadLanguageTarget(language);
+		loadTemplates(language);
+	}
+
+	void loadLanguageTarget(String language) {
+		String targetName = "org.antlr.v4.codegen."+language+"Target";
+		try {
+			Class c = Class.forName(targetName);
+			target = (Target)c.newInstance();
+		}
+		catch (ClassNotFoundException cnfe) {
+			target = new Target(); // use default
+		}
+		catch (InstantiationException ie) {
+			g.tool.errMgr.toolError(ErrorType.CANNOT_CREATE_TARGET_GENERATOR,
+						 targetName,
+						 ie);
+		}
+		catch (IllegalAccessException cnfe) {
+			g.tool.errMgr.toolError(ErrorType.CANNOT_CREATE_TARGET_GENERATOR,
+						 targetName,
+						 cnfe);
+		}
+	}
+
+	public void loadTemplates(String language) {
+		templates = new STGroupFile(TEMPLATE_ROOT+"/"+language+"/"+language+".stg");
+//		if ( EMIT_TEMPLATE_DELIMITERS ) {
+//			templates.emitDebugStartStopStrings(true);
+//			templates.doNotEmitDebugStringsForTemplate("codeFileExtension");
+//			templates.doNotEmitDebugStringsForTemplate("headerFileExtension");
+//		}		
+	}
+
+	public abstract OutputModelObject buildOutputModel();
+
+	public void write() {
+		OutputModelObject root = buildOutputModel();
+
+		OutputModelWalker walker = new OutputModelWalker(g.tool, templates,
+														 ParserGenerator.modelToTemplateMap);
+		ST outputFileST = walker.walk(root);
+		
+		// WRITE FILES
+		try {
+			target.genRecognizerFile(g.tool,this,g,outputFileST);
+			if ( templates.isDefined("headerFile") ) {
+				ST extST = templates.getInstanceOf("headerFileExtension");
+				ST headerFileST = null;
+				target.genRecognizerHeaderFile(g.tool,this,g,headerFileST,extST.render());
+			}
+//			// write out the vocab interchange file; used by antlr,
+//			// does not change per target
+//			ST tokenVocabSerialization = genTokenVocabOutput();
+//			String vocabFileName = getVocabFileName();
+//			if ( vocabFileName!=null ) {
+//				write(tokenVocabSerialization, vocabFileName);
+//			}
+			//System.out.println(outputFileST.getDOTForDependencyGraph(false));
+		}
+		catch (IOException ioe) {
+			g.tool.errMgr.toolError(ErrorType.CANNOT_WRITE_FILE,
+						 getVocabFileName(),
+						 ioe);
+		}
+	}
+
+	public void write(ST code, String fileName) throws IOException {
+		long start = System.currentTimeMillis();
+		Writer w = g.tool.getOutputFile(g, fileName);
+		// Write the output to a StringWriter
+		STWriter wr = new AutoIndentWriter(w);
+		wr.setLineWidth(lineWidth);
+		code.write(wr);
+		w.close();
+		long stop = System.currentTimeMillis();
+		System.out.println("render time for "+fileName+": "+(int)(stop-start)+"ms");
+	}
+
+	/** Generate TParser.java and TLexer.java from T.g if combined, else
+	 *  just use T.java as output regardless of type.
+	 */
+	public String getRecognizerFileName() {
+		ST extST = templates.getInstanceOf("codeFileExtension");
+		String recognizerName = g.getRecognizerName();
+		return recognizerName+extST.render();
+	}
+
+	/** What is the name of the vocab file generated for this grammar?
+	 *  Returns null if no .tokens file should be generated.
+	 */
+	public String getVocabFileName() {
+//		if ( g.isBuiltFromString() ) {
+//			return null;
+//		}
+		return g.name+VOCAB_FILE_EXTENSION;
+	}
+}
diff --git a/tool/src/org/antlr/v4/codegen/OutputModelWalker.java b/tool/src/org/antlr/v4/codegen/OutputModelWalker.java
new file mode 100644
index 000000000..bbac36b9c
--- /dev/null
+++ b/tool/src/org/antlr/v4/codegen/OutputModelWalker.java
@@ -0,0 +1,76 @@
+package org.antlr.v4.codegen;
+
+import org.antlr.v4.Tool;
+import org.antlr.v4.codegen.src.OutputModelObject;
+import org.antlr.v4.tool.ErrorType;
+import org.stringtemplate.v4.ST;
+import org.stringtemplate.v4.STGroup;
+import org.stringtemplate.v4.compiler.FormalArgument;
+
+import java.lang.reflect.Field;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+
+/** Convert output model tree to template hierarchy */
+public class OutputModelWalker {
+	Tool tool;
+	STGroup templates;
+	Map<Class, String> modelToTemplateMap;
+
+	public OutputModelWalker(Tool tool,
+							 STGroup templates,
+							 Map<Class, String> modelToTemplateMap)
+	{
+		this.tool = tool;
+		this.templates = templates;
+		this.modelToTemplateMap = modelToTemplateMap;
+	}
+	
+	public ST walk(OutputModelObject omo) {
+		// CREATE TEMPLATE FOR THIS OUTPUT OBJECT
+		String templateName = modelToTemplateMap.get(omo.getClass());
+		ST st = templates.getInstanceOf(templateName);
+		if ( st.impl.formalArguments== FormalArgument.UNKNOWN ) {
+			tool.errMgr.toolError(ErrorType.CODE_TEMPLATE_ARG_ISSUE, templateName, "<none>");
+			return st;
+		}
+		// todo: chk arg-field mismtch
+		Set<String> argNames = st.impl.formalArguments.keySet();
+		String arg = argNames.iterator().next(); // should be just one
+
+		// PASS IN OUTPUT OBJECT TO TEMPLATE
+		st.add(arg, omo); // set template attribute of correct name
+
+		for (String fieldName : omo.getChildren()) {
+			if ( argNames.contains(fieldName) ) continue; // they won't use so don't compute
+			try {
+				Field fi = omo.getClass().getField(fieldName);
+				Object o = fi.get(omo);
+				if ( o instanceof OutputModelObject ) {
+					OutputModelObject nestedOmo = (OutputModelObject)o;
+					ST nestedST = walk(nestedOmo);
+					st.add(fieldName, nestedST);
+				}
+				else if ( o instanceof Collection) {
+					Collection<? extends OutputModelObject> nestedOmos = (Collection)o;
+					for (OutputModelObject nestedOmo : nestedOmos) {
+						ST nestedST = walk(nestedOmo);
+						st.add(fieldName, nestedST);
+					}
+				}
+				else if ( o!=null ) {
+					tool.errMgr.toolError(ErrorType.CODE_TEMPLATE_ARG_ISSUE, templateName, fieldName);
+				}
+			}
+			catch (NoSuchFieldException nsfe) {
+				tool.errMgr.toolError(ErrorType.CODE_TEMPLATE_ARG_ISSUE, templateName, fieldName);
+			}
+			catch (IllegalAccessException iae) {
+				tool.errMgr.toolError(ErrorType.CODE_TEMPLATE_ARG_ISSUE, templateName, fieldName);
+			}
+		}
+		return st;
+	}
+
+}
diff --git a/tool/src/org/antlr/v4/codegen/ParserGenerator.java b/tool/src/org/antlr/v4/codegen/ParserGenerator.java
new file mode 100644
index 000000000..b71bb78d0
--- /dev/null
+++ b/tool/src/org/antlr/v4/codegen/ParserGenerator.java
@@ -0,0 +1,31 @@
+package org.antlr.v4.codegen;
+
+import org.antlr.v4.codegen.src.OutputModelObject;
+import org.antlr.v4.codegen.src.Parser;
+import org.antlr.v4.codegen.src.ParserFile;
+import org.antlr.v4.codegen.src.RuleFunction;
+import org.antlr.v4.tool.Grammar;
+
+import java.util.HashMap;
+import java.util.Map;
+
+
+/** */
+public class ParserGenerator extends CodeGenerator {
+	public static final Map<Class, String> modelToTemplateMap = new HashMap<Class, String>() {{
+		put(ParserFile.class, "parserFile");
+		put(Parser.class, "parser");
+		put(RuleFunction.class, "parserFunction");
+	}};
+
+	public ParserGenerator(Grammar g) {
+		super(g);
+	}
+
+	public OutputModelObject buildOutputModel() {
+		Parser p = new Parser(g);
+		ParserFile f = new ParserFile(p, getRecognizerFileName());
+
+		return f;
+	}
+}
diff --git a/tool/src/org/antlr/v4/codegen/Target.java b/tool/src/org/antlr/v4/codegen/Target.java
index 5b0fc7655..3cb6560ce 100644
--- a/tool/src/org/antlr/v4/codegen/Target.java
+++ b/tool/src/org/antlr/v4/codegen/Target.java
@@ -1,7 +1,11 @@
 package org.antlr.v4.codegen;
 
-import org.antlr.analysis.Label;
-import org.antlr.tool.ErrorManager;
+import org.antlr.v4.Tool;
+import org.antlr.v4.automata.Label;
+import org.antlr.v4.tool.Grammar;
+import org.stringtemplate.v4.ST;
+
+import java.io.IOException;
 
 /** */
 public class Target {
@@ -32,6 +36,26 @@ public class Target {
 		ANTLRLiteralCharValueEscape['\''] = "\\'";
 	}
 
+	protected void genRecognizerFile(Tool tool,
+									 CodeGenerator generator,
+									 Grammar grammar,
+									 ST outputFileST)
+		throws IOException
+	{
+		String fileName = generator.getRecognizerFileName();
+		generator.write(outputFileST, fileName);
+	}
+
+	protected void genRecognizerHeaderFile(Tool tool,
+										   CodeGenerator generator,
+										   Grammar grammar,
+										   ST headerFileST,
+										   String extName) // e.g., ".h"
+		throws IOException
+	{
+		// no header file by default
+	}
+	
 	/** Given a literal like (the 3 char sequence with single quotes) 'a',
 	 *  return the int value of 'a'. Convert escape sequences here also.
 	 */
@@ -43,8 +67,8 @@ public class Target {
 			case 4 :
 				// '\x'  (antlr lexer will catch invalid char)
 				if ( Character.isDigit(literal.charAt(2)) ) {
-					ErrorManager.error(ErrorManager.MSG_SYNTAX_ERROR,
-									   "invalid char literal: "+literal);
+//					ErrorManager.error(ErrorManager.MSG_SYNTAX_ERROR,
+//									   "invalid char literal: "+literal);
 					return -1;
 				}
 				int escChar = literal.charAt(2);
@@ -59,8 +83,8 @@ public class Target {
 				String unicodeChars = literal.substring(3,literal.length()-1);
 				return Integer.parseInt(unicodeChars, 16);
 			default :
-				ErrorManager.error(ErrorManager.MSG_SYNTAX_ERROR,
-								   "invalid char literal: "+literal);
+//				ErrorManager.error(ErrorManager.MSG_SYNTAX_ERROR,
+//								   "invalid char literal: "+literal);
 				return -1;
 		}
 	}
@@ -102,7 +126,6 @@ public class Target {
 	 */
 	public static String getANTLRCharLiteralForChar(int c) {
 		if ( c< Label.MIN_CHAR_VALUE ) {
-			ErrorManager.internalError("invalid char value "+c);
 			return "'<INVALID>'";
 		}
 		if ( c<ANTLRLiteralCharValueEscape.length && ANTLRLiteralCharValueEscape[c]!=null ) {
diff --git a/tool/src/org/antlr/v4/codegen/src/BitSetDef.java b/tool/src/org/antlr/v4/codegen/src/BitSetDef.java
index e6d949c6c..c8b20f61d 100644
--- a/tool/src/org/antlr/v4/codegen/src/BitSetDef.java
+++ b/tool/src/org/antlr/v4/codegen/src/BitSetDef.java
@@ -3,7 +3,7 @@ package org.antlr.v4.codegen.src;
 import org.antlr.v4.misc.IntSet;
 
 /** */
-public class BitSetDef {
+public class BitSetDef extends OutputModelObject {
 	String name;
 	IntSet[] set;
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/Choice.java b/tool/src/org/antlr/v4/codegen/src/Choice.java
index d2a52fa90..af0acd690 100644
--- a/tool/src/org/antlr/v4/codegen/src/Choice.java
+++ b/tool/src/org/antlr/v4/codegen/src/Choice.java
@@ -1,12 +1,21 @@
 package org.antlr.v4.codegen.src;
 
-import org.antlr.v4.automata.DFA;
+import org.antlr.v4.tool.Alternative;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** */
 public class Choice extends SrcOp {
-	//public DFADef dfaDef; ???	
-	public DFA dfa;
+	public DFADef dfaDef;
 	public List<CodeBlock> alts;
+
+	public Choice(Alternative[] alts) {
+		
+	}
+
+	@Override
+	public List<String> getChildren() {
+		return new ArrayList<String>() {{ add("alts"); }};
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/CodeBlock.java b/tool/src/org/antlr/v4/codegen/src/CodeBlock.java
index 0a083157d..4576b9d40 100644
--- a/tool/src/org/antlr/v4/codegen/src/CodeBlock.java
+++ b/tool/src/org/antlr/v4/codegen/src/CodeBlock.java
@@ -1,8 +1,14 @@
 package org.antlr.v4.codegen.src;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** */
 public class CodeBlock extends SrcOp {
 	public List<SrcOp> ops;
+
+	@Override
+	public List<String> getChildren() {
+		return new ArrayList<String>() {{ add("ops"); }};
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/DFADef.java b/tool/src/org/antlr/v4/codegen/src/DFADef.java
index fa618f703..d6e83db76 100644
--- a/tool/src/org/antlr/v4/codegen/src/DFADef.java
+++ b/tool/src/org/antlr/v4/codegen/src/DFADef.java
@@ -3,7 +3,7 @@ package org.antlr.v4.codegen.src;
 import org.antlr.v4.automata.DFA;
 
 /** */
-public class DFADef {
+public class DFADef extends OutputModelObject {
 	public String name;
 	public DFA dfa;
 	
diff --git a/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlock.java b/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlock.java
index e4a66846f..90ce8c7ae 100644
--- a/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlock.java
+++ b/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlock.java
@@ -1,5 +1,10 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.tool.Alternative;
+
 /** */
 public class LL1OptionalBlock extends OptionalBlock {
+	public LL1OptionalBlock(Alternative[] alts) {
+		super(alts);
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlockSingleAlt.java b/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlockSingleAlt.java
index 6add1a283..dfce66a4d 100644
--- a/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlockSingleAlt.java
+++ b/tool/src/org/antlr/v4/codegen/src/LL1OptionalBlockSingleAlt.java
@@ -1,5 +1,10 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.tool.Alternative;
+
 /** */
 public class LL1OptionalBlockSingleAlt extends OptionalBlock {
+	public LL1OptionalBlockSingleAlt(Alternative[] alts) {
+		super(alts);
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/LLStarOptionalBlock.java b/tool/src/org/antlr/v4/codegen/src/LLStarOptionalBlock.java
index d85ffa435..093475eff 100644
--- a/tool/src/org/antlr/v4/codegen/src/LLStarOptionalBlock.java
+++ b/tool/src/org/antlr/v4/codegen/src/LLStarOptionalBlock.java
@@ -1,5 +1,10 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.tool.Alternative;
+
 /** */
 public class LLStarOptionalBlock extends OptionalBlock {
+	public LLStarOptionalBlock(Alternative[] alts) {
+		super(alts);
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/LLkOptionalBlock.java b/tool/src/org/antlr/v4/codegen/src/LLkOptionalBlock.java
index 3597c8ef5..84e6ce919 100644
--- a/tool/src/org/antlr/v4/codegen/src/LLkOptionalBlock.java
+++ b/tool/src/org/antlr/v4/codegen/src/LLkOptionalBlock.java
@@ -1,5 +1,10 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.tool.Alternative;
+
 /** */
 public class LLkOptionalBlock extends OptionalBlock {
+	public LLkOptionalBlock(Alternative[] alts) {
+		super(alts);
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/OptionalBlock.java b/tool/src/org/antlr/v4/codegen/src/OptionalBlock.java
index 691181426..3ce0063a7 100644
--- a/tool/src/org/antlr/v4/codegen/src/OptionalBlock.java
+++ b/tool/src/org/antlr/v4/codegen/src/OptionalBlock.java
@@ -1,5 +1,17 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.tool.Alternative;
+
+import java.util.List;
+
 /** */
 public class OptionalBlock extends Choice {
+	public OptionalBlock(Alternative[] alts) {
+		super(alts);
+	}
+
+	@Override
+	public List<String> getChildren() {
+		return super.getChildren();
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/OutputModelObject.java b/tool/src/org/antlr/v4/codegen/src/OutputModelObject.java
new file mode 100644
index 000000000..f1c48f512
--- /dev/null
+++ b/tool/src/org/antlr/v4/codegen/src/OutputModelObject.java
@@ -0,0 +1,19 @@
+package org.antlr.v4.codegen.src;
+
+import java.util.List;
+
+/** */
+public abstract class OutputModelObject {
+	//public abstract ST getSt();
+
+	/** If the output model object encloses some other model objects,
+	 *  we need to be able to walk them. Rather than make each class
+	 *  properly walk any nested objects, I'm going to use a generic
+	 *  external walker. This method lets me look at the output model
+	 *  as a homogeneous tree structure.  Returns a list of field names
+	 *  of type OutputModelObject that should be walked to complete model.
+	 */
+	public List<String> getChildren() {
+		return null;
+	}
+}
diff --git a/tool/src/org/antlr/v4/codegen/src/Parser.java b/tool/src/org/antlr/v4/codegen/src/Parser.java
index 469c8c3fe..6b609bf58 100644
--- a/tool/src/org/antlr/v4/codegen/src/Parser.java
+++ b/tool/src/org/antlr/v4/codegen/src/Parser.java
@@ -1,11 +1,26 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.misc.IntSet;
 import org.antlr.v4.tool.Grammar;
+import org.antlr.v4.tool.Rule;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** */
-public class Parser {
-	public Grammar g;
-	public List<RuleFunction> funcs;
+public class Parser extends OutputModelObject {
+	public String name;
+	public List<RuleFunction> funcs = new ArrayList<RuleFunction>();
+	public List<DFADef> dfaDefs;
+	public List<IntSet> bitsetDefs;
+
+	public Parser(Grammar g) {		
+		name = g.getRecognizerName();
+		for (Rule r : g.rules.values()) funcs.add( new RuleFunction(r) );
+	}
+
+	@Override
+	public List<String> getChildren() {
+		return new ArrayList<String>() {{ add("funcs"); add("dfaDefs"); }};
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/ParserFile.java b/tool/src/org/antlr/v4/codegen/src/ParserFile.java
index 05274e52e..bfbc4be62 100644
--- a/tool/src/org/antlr/v4/codegen/src/ParserFile.java
+++ b/tool/src/org/antlr/v4/codegen/src/ParserFile.java
@@ -1,6 +1,16 @@
 package org.antlr.v4.codegen.src;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /** */
-public class ParserFile {
+public class ParserFile extends OutputModelObject {
+	public String fileName;
 	public Parser parser;
+	public ParserFile(Parser p, String fileName) { parser = p; this.fileName = fileName; }
+
+	@Override
+	public List<String> getChildren() {
+		return new ArrayList<String>() {{ add("parser"); }};
+	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/RuleFunction.java b/tool/src/org/antlr/v4/codegen/src/RuleFunction.java
index 0513ee53c..abc0f4be8 100644
--- a/tool/src/org/antlr/v4/codegen/src/RuleFunction.java
+++ b/tool/src/org/antlr/v4/codegen/src/RuleFunction.java
@@ -10,7 +10,7 @@ import java.util.Collection;
 import java.util.List;
 
 /** */
-public class RuleFunction {
+public class RuleFunction extends OutputModelObject {
 	public String name;
 	public List<String> modifiers;
     public Collection<Attribute> args;
@@ -33,12 +33,17 @@ public class RuleFunction {
 		}
 		modifiers = Utils.nodesToStrings(r.modifiers);
 
-		args = r.args.attributes.values();
-		retvals = r.retvals.attributes.values();
-		ruleScopeDecls = r.scope.attributes.values();
+		if ( r.args!=null ) args = r.args.attributes.values();
+		if ( r.retvals!=null ) retvals = r.retvals.attributes.values();
+		if ( r.scope!=null ) ruleScopeDecls = r.scope.attributes.values();
 		ruleLabels = r.getLabelNames();
 		tokenLabels = r.getTokenRefs();
 		exceptions = Utils.nodesToStrings(r.exceptionActions);
-		finallyAction = r.finallyAction.getText();
+		if ( r.finallyAction!=null ) finallyAction = r.finallyAction.getText();
+	}
+
+	@Override
+	public List<String> getChildren() {
+		return new ArrayList<String>() {{ add("code"); }};
 	}
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/SrcOp.java b/tool/src/org/antlr/v4/codegen/src/SrcOp.java
index 5a37e81fb..5f83d3b29 100644
--- a/tool/src/org/antlr/v4/codegen/src/SrcOp.java
+++ b/tool/src/org/antlr/v4/codegen/src/SrcOp.java
@@ -3,6 +3,6 @@ package org.antlr.v4.codegen.src;
 import org.antlr.v4.tool.GrammarAST;
 
 /** */
-public class SrcOp {
+public class SrcOp extends OutputModelObject {
 	public GrammarAST ast;	
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/Sync.java b/tool/src/org/antlr/v4/codegen/src/Sync.java
index f0c597bf5..764c90ecc 100644
--- a/tool/src/org/antlr/v4/codegen/src/Sync.java
+++ b/tool/src/org/antlr/v4/codegen/src/Sync.java
@@ -1,5 +1,5 @@
 package org.antlr.v4.codegen.src;
 
 /** */
-public class Sync {
+public class Sync extends SrcOp {
 }
diff --git a/tool/src/org/antlr/v4/codegen/src/dbg.java b/tool/src/org/antlr/v4/codegen/src/dbg.java
index cdc4ef95f..e81067199 100644
--- a/tool/src/org/antlr/v4/codegen/src/dbg.java
+++ b/tool/src/org/antlr/v4/codegen/src/dbg.java
@@ -1,5 +1,5 @@
 package org.antlr.v4.codegen.src;
 
 /** */
-public class dbg {
+public class dbg extends OutputModelObject {
 }
diff --git a/tool/src/org/antlr/v4/misc/Utils.java b/tool/src/org/antlr/v4/misc/Utils.java
index 68c0ab32d..4dd91544d 100644
--- a/tool/src/org/antlr/v4/misc/Utils.java
+++ b/tool/src/org/antlr/v4/misc/Utils.java
@@ -96,6 +96,7 @@ public class Utils {
 	}
 
 	public static <T extends GrammarAST> List<String> nodesToStrings(List<T> nodes) {
+		if ( nodes == null ) return null;
 		List<String> a = new ArrayList<String>();
 		for (T t : nodes) a.add(t.getText());
 		return a;
diff --git a/tool/src/org/antlr/v4/tool/ErrorType.java b/tool/src/org/antlr/v4/tool/ErrorType.java
index c28d8b483..cf51b6bb1 100644
--- a/tool/src/org/antlr/v4/tool/ErrorType.java
+++ b/tool/src/org/antlr/v4/tool/ErrorType.java
@@ -55,13 +55,13 @@ public enum ErrorType {
 
 	INTERNAL_ERROR(ErrorSeverity.ERROR, true, true),
 	INTERNAL_WARNING(ErrorSeverity.ERROR, true, true),
-	ERROR_CREATING_ARTIFICIAL_RULE(ErrorSeverity.ERROR, true, true),
 	TOKENS_FILE_SYNTAX_ERROR(ErrorSeverity.ERROR, true, true),
 	CANNOT_GEN_DOT_FILE(ErrorSeverity.ERROR, true, true),
 
 	// Code generation errors
 	MISSING_CODE_GEN_TEMPLATES(ErrorSeverity.ERROR, false, true),
 	CANNOT_CREATE_TARGET_GENERATOR(ErrorSeverity.ERROR, false, true),
+	CODE_TEMPLATE_ARG_ISSUE(ErrorSeverity.ERROR, false, true),
 
 	// Grammar errors
 	SYNTAX_ERROR(ErrorSeverity.ERROR, true, true),
diff --git a/tool/src/org/antlr/v4/tool/Grammar.java b/tool/src/org/antlr/v4/tool/Grammar.java
index ba6f4e81d..f26e26423 100644
--- a/tool/src/org/antlr/v4/tool/Grammar.java
+++ b/tool/src/org/antlr/v4/tool/Grammar.java
@@ -536,6 +536,18 @@ public class Grammar implements AttributeResolver {
         }
 	}
 
+	public String getOption(String key) {
+		if ( options==null ) return null;
+		return options.get(key);
+	}
+
+	public String getOption(String key, String defaultValue) {
+		if ( options==null ) return defaultValue;
+		String v = options.get(key);
+		if ( v!=null ) return v;
+		return defaultValue;
+	}
+
 	public static Map<String,String> getStringLiteralAliasesFromLexerRules(GrammarRootAST ast) {
 		GrammarAST combinedRulesRoot =
 			(GrammarAST)ast.getFirstChildWithType(ANTLRParser.RULES);
diff --git a/tool/src/org/antlr/v4/tool/Rule.java b/tool/src/org/antlr/v4/tool/Rule.java
index c299a4bb7..5f376214e 100644
--- a/tool/src/org/antlr/v4/tool/Rule.java
+++ b/tool/src/org/antlr/v4/tool/Rule.java
@@ -125,14 +125,18 @@ public class Rule implements AttributeResolver {
 	// TODO: move to code gen InvokeRule function? is only place we ref?
 	public Set<String> getRuleRefs() {
         Set<String> refs = new HashSet<String>();
-        for (Alternative a : alt) refs.addAll(a.ruleRefs.keySet());
+		for (int i=1; i<=numberOfAlts; i++) {
+			refs.addAll(alt[i].ruleRefs.keySet());
+		}
         return refs;
     }
 
 	public Set<String> getTokenRefs() {
         Set<String> refs = new HashSet<String>();
-        for (Alternative a : alt) refs.addAll(a.tokenRefs.keySet());
-        return refs;
+		for (int i=1; i<=numberOfAlts; i++) {
+			refs.addAll(alt[i].tokenRefs.keySet());
+		}
+		return refs;
     }
 
     public Set<String> getLabelNames() {