got basic tree parser ^(A B) stuff in.

[git-p4: depot-paths = "//depot/code/antlr4/main/": change = 9068]

tool/resources/org/antlr/v4/tool/templates/codegen/Java/Java.stg

@@ -35,6 +35,10 @@ import java.util.ArrayList;
 <parser>
 >>
 
+TreeParserFile(file, parser, namedActions) ::= <<
+<ParserFile(...)>
+>>
+
 ListenerFile(listener, header) ::= <<
 <header>
 import org.antlr.v4.runtime.tree.ParseTreeListener;
@@ -106,6 +110,10 @@ public class <parser.name> extends Parser {
 }
 >>
 
+TreeParserModel(parser, scopes, funcs, atn, sempredFuncs) ::= <<
+<Parser(...)>
+>>
+
 dumpActions(recog, argFuncs, actionFuncs, sempredFuncs) ::= <<
 <if(actionFuncs)>
 public void action(RuleContext _localctx, int ruleIndex, int actionIndex) {
@@ -344,6 +352,19 @@ cases(ttypes) ::= <<
 <ttypes:{t | case <t>:}; separator="\n">
 >>
 
+MatchTree(t, elems) ::= <<
+// match tree
+<elems; separator="\n">
+>>
+
+MatchDOWN(m) ::= <<
+move(<m.stateNumber>); match(Token.DOWN);
+>>
+
+MatchUP(m) ::= <<
+move(<m.stateNumber>); match(Token.UP);
+>>
+
 InvokeRule(r, argExprsChunks) ::= <<
 move(<r.stateNumber>); <if(r.labels)><r.labels:{l | <labelref(l)> = }><endif><r.name>(<argExprsChunks:{e| <e>}>);
 >>

tool/src/org/antlr/v4/Tool.java

@@ -263,6 +263,7 @@ public class Tool {
 		// BUILD ATN FROM AST
 		ATNFactory factory;
 		if ( g.isLexer() ) factory = new LexerATNFactory((LexerGrammar)g);
+		else if ( g.isTreeGrammar() ) factory = new TreeParserATNFactory(g);
 		else factory = new ParserATNFactory(g);
 		g.atn = factory.createATN();
 

tool/src/org/antlr/v4/automata/ATNFactory.java

@@ -69,7 +69,7 @@ public interface ATNFactory {
 
 	Handle set(GrammarAST associatedAST, List<GrammarAST> alts, boolean invert);
 
-	Handle tree(List<Handle> els);
+	Handle tree(GrammarAST node, List<Handle> els);
 
 	Handle range(GrammarAST a, GrammarAST b);
 

tool/src/org/antlr/v4/automata/ParserATNFactory.java

@@ -49,7 +49,7 @@ import java.util.*;
 public class ParserATNFactory implements ATNFactory {
 	public Grammar g;
 	public Rule currentRule;
-	ATN atn;
+	public ATN atn;
 
 	public ParserATNFactory(Grammar g) { this.g = g; atn = new ATN(); }
 
@@ -133,8 +133,8 @@ public class ParserATNFactory implements ATNFactory {
 		return new Handle(left, right);
 	}
 
-	public Handle tree(List<Handle> els) {
-		return null;
+	public Handle tree(GrammarAST node, List<Handle> els) {
+		throw new UnsupportedOperationException("^(...) not allowed in non-tree grammar");
 	}
 
 	/** Not valid for non-lexers */
@@ -142,19 +142,6 @@ public class ParserATNFactory implements ATNFactory {
 		throw new UnsupportedOperationException();
 	}
 
-	/** ~atom only */
-	/*
-	public Handle not(GrammarAST node) {
-		ATNState left = newState(node);
-		ATNState right = newState(node);
-		int ttype = getTokenType((GrammarAST) node.getChild(0));
-		left.transition = new NotAtomTransition(ttype, right);
-		right.incidentTransition = left.transition;
-		node.atnState = left;
-		return new Handle(left, right);
-	}
-	*/
-
 	protected int getTokenType(GrammarAST atom) {
 		int ttype;
 		if ( g.isLexer() ) {
@@ -319,6 +306,10 @@ public class ParserATNFactory implements ATNFactory {
 //	}
 
 	public Handle alt(List<Handle> els) {
+		return elemList(els);
+	}
+
+	public Handle elemList(List<Handle> els) {
 		Handle prev = null;
 		for (Handle el : els) { // hook up elements
 			if ( prev!=null ) epsilon(prev.right, el.left);
@@ -327,7 +318,7 @@ public class ParserATNFactory implements ATNFactory {
 		Handle first = els.get(0);
 		Handle last = els.get(els.size()-1);
 		if ( first==null || last==null ) {
-			g.tool.errMgr.toolError(ErrorType.INTERNAL_ERROR, "alt Handle has first|last == null");
+			g.tool.errMgr.toolError(ErrorType.INTERNAL_ERROR, "element list has first|last == null");
 		}
 		return new Handle(first.left, last.right);
 	}

tool/src/org/antlr/v4/automata/TreeParserATNFactory.java

@@ -0,0 +1,76 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.automata;
+
+import org.antlr.v4.tool.*;
+
+import java.util.List;
+
+/** Build ATNs for tree grammars */
+public class TreeParserATNFactory extends ParserATNFactory {
+	public TreeParserATNFactory(Grammar g) {
+		super(g);
+	}
+
+	/** x y z from ^(x y z) becomes o-x->o-DOWN->o-y->o-z->o-UP->o */
+	public Handle tree(GrammarAST node, List<Handle> els) {
+		Handle h = elemList(els);
+		return h;
+
+//		ATNState first = h.left;
+//		ATNState last = h.right;
+//		node.atnState = first;
+//
+//		// find root transition first side node
+//		ATNState p = first;
+//		while ( p.transition(0) instanceof EpsilonTransition ||
+//				p.transition(0) instanceof PredicateTransition ||
+//				p.transition(0) instanceof RangeTransition ||
+//				p.transition(0) instanceof ActionTransition )
+//		{
+//			p = p.transition(0).target;
+//		}
+//		ATNState rootLeftNode = p;
+//		ATNState rootRightNode = rootLeftNode.transition(0).target;
+//		ATNState downLeftNode = newState(node);
+//		downLeftNode.transition = new AtomTransition(Token.DOWN, rootRightNode);
+//		rootRightNode.incidentTransition = downLeftNode.transition;
+//		rootLeftNode.transition.target = downLeftNode;
+//		downLeftNode.incidentTransition = rootLeftNode.transition;
+//
+//		ATNState upRightNode = newState(node);
+//		last.transition = new AtomTransition(Token.UP, upRightNode);
+//		upRightNode.incidentTransition = last.transition;
+//		last = upRightNode;
+//
+//		return new Handle(first, last);
+	}
+
+}

tool/src/org/antlr/v4/codegen/CodeGenPipeline.java

@@ -44,6 +44,9 @@ public class CodeGenPipeline {
 		if ( g.isLexer() ) {
 			gen.writeRecognizer(gen.generateLexer());
 		}
+		else if ( g.isTreeGrammar() ) {
+			gen.writeRecognizer(gen.generateTreeParser());
+		}
 		else {
 			gen.writeRecognizer(gen.generateParser());
 			gen.writeListener(gen.generateListener());

tool/src/org/antlr/v4/codegen/CodeGenerator.java

@@ -32,16 +32,12 @@ package org.antlr.v4.codegen;
 import org.antlr.v4.Tool;
 import org.antlr.v4.codegen.model.OutputModelObject;
 import org.antlr.v4.runtime.Token;
-import org.antlr.v4.tool.ErrorType;
-import org.antlr.v4.tool.Grammar;
+import org.antlr.v4.tool.*;
 import org.stringtemplate.v4.*;
 
-import java.io.IOException;
-import java.io.Writer;
-import java.lang.reflect.Constructor;
-import java.lang.reflect.InvocationTargetException;
-import java.util.HashMap;
-import java.util.Map;
+import java.io.*;
+import java.lang.reflect.*;
+import java.util.*;
 
 /** General controller for code gen.  Can instantiate sub generator(s).
  */
@@ -171,6 +167,29 @@ public class CodeGenerator {
 		return st;
 	}
 
+	public ST generateTreeParser() {
+		OutputModelFactory factory = new TreeParserFactory(this);
+
+		// CREATE OUTPUT MODEL FROM GRAMMAR OBJ AND AST WITHIN RULES
+		OutputModelController controller = new OutputModelController(factory);
+		if ( g.hasASTOption() ) {
+			controller.addExtension( new ParserASTExtension(factory) );
+		}
+		factory.setController(controller);
+
+		OutputModelObject outputModel = controller.buildTreeParserOutputModel();
+
+		OutputModelWalker walker = new OutputModelWalker(tool, templates);
+		ST st = walker.walk(outputModel);
+
+		if ( tool.launch_ST_inspector ) {
+			st.inspect();
+			//if ( templates.isDefined("headerFile") ) headerFileST.inspect();
+		}
+
+		return st;
+	}
+
 	public ST generateListener() {
 		OutputModelFactory factory = new ParserFactory(this);
 

tool/src/org/antlr/v4/codegen/CodeGeneratorExtension.java

@@ -52,6 +52,10 @@ public class CodeGeneratorExtension {
 
 	public Lexer lexer(Lexer l) { return l; }
 
+	public TreeParserFile treeParserFile(TreeParserFile f) { return f; }
+
+	public TreeParserModel treeParser(TreeParserModel p) { return p; }
+
 	public RuleFunction rule(RuleFunction rf) { return rf; }
 
 	public List<SrcOp> rulePostamble(List<SrcOp> ops) { return ops; }
@@ -72,6 +76,8 @@ public class CodeGeneratorExtension {
 
 	public List<SrcOp> wildcard(List<SrcOp> ops) { return ops; }
 
+	public MatchTree tree(MatchTree matchTree) { return matchTree; }
+
 	// ACTIONS
 
 	public List<SrcOp> action(List<SrcOp> ops) { return ops; }

tool/src/org/antlr/v4/codegen/DefaultOutputModelFactory.java

@@ -75,6 +75,21 @@ public abstract class DefaultOutputModelFactory extends BlankOutputModelFactory
 
 	public int getTreeLevel() { return controller.treeLevel; }
 
+	@Override
+	public TreeParserFile treeParserFile(String fileName) {
+		return null;
+	}
+
+	@Override
+	public TreeParserModel treeParser(TreeParserFile file) {
+		return null;
+	}
+
+	@Override
+	public MatchTree tree(GrammarAST treeBeginAST, List<? extends SrcOp> omos) {
+		throw new UnsupportedOperationException("^(...) in non-tree grammar");
+	}
+
 	// MISC
 
 	public static List<SrcOp> list(Object... values) {

tool/src/org/antlr/v4/codegen/OutputModelController.java

@@ -102,6 +102,21 @@ public class OutputModelController {
 		return file;
 	}
 
+	public OutputModelObject buildTreeParserOutputModel() {
+		Grammar g = delegate.getGrammar();
+		CodeGenerator gen = delegate.getGenerator();
+		TreeParserFile file = treeParserFile(gen.getRecognizerFileName());
+		setRoot(file);
+		Parser parser = treeParser(file);
+		file.parser = parser;
+
+		for (Rule r : g.rules.values()) {
+			buildRuleFunction(parser, r);
+		}
+
+		return file;
+	}
+
 	public OutputModelObject buildListenerOutputModel() {
 		CodeGenerator gen = delegate.getGenerator();
 		return new ListenerFile(delegate, gen.getListenerFileName());
@@ -132,6 +147,18 @@ public class OutputModelController {
 		return new Lexer(delegate, file);
 	}
 
+	public TreeParserFile treeParserFile(String fileName) {
+		TreeParserFile f = delegate.treeParserFile(fileName);
+		for (CodeGeneratorExtension ext : extensions) f = ext.treeParserFile(f);
+		return f;
+	}
+
+	public TreeParserModel treeParser(TreeParserFile file) {
+		TreeParserModel p = delegate.treeParser(file);
+		for (CodeGeneratorExtension ext : extensions) p = ext.treeParser(p);
+		return p;
+	}
+
 	/** Create RuleFunction per rule and update sempreds,actions of parser
 	 *  output object with stuff found in r.
 	 */
@@ -342,6 +369,12 @@ public class OutputModelController {
 		return ops;
 	}
 
+	public MatchTree tree(GrammarAST treeBeginAST, List<? extends SrcOp> omos) {
+		MatchTree matchTree = delegate.tree(treeBeginAST, omos);
+		for (CodeGeneratorExtension ext : extensions) matchTree = ext.tree(matchTree);
+		return matchTree;
+	}
+
 	public Choice getChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts, GrammarAST label) {
 		Choice c = delegate.getChoiceBlock(blkAST, alts, label);
 		for (CodeGeneratorExtension ext : extensions) c = ext.getChoiceBlock(c);

tool/src/org/antlr/v4/codegen/OutputModelFactory.java

@@ -52,6 +52,10 @@ public interface OutputModelFactory {
 
 	Lexer lexer(LexerFile file);
 
+	TreeParserFile treeParserFile(String fileName);
+
+	TreeParserModel treeParser(TreeParserFile file);
+
 	RuleFunction rule(Rule r);
 
 	List<SrcOp> rulePostamble(RuleFunction function, Rule r);
@@ -84,6 +88,8 @@ public interface OutputModelFactory {
 
 	List<SrcOp> wildcard(GrammarAST ast, GrammarAST labelAST, GrammarAST astOp);
 
+	MatchTree tree(GrammarAST treeBeginAST, List<? extends SrcOp> omos);
+
 	Choice getChoiceBlock(BlockAST blkAST, List<CodeBlockForAlt> alts, GrammarAST label);
 
 	Choice getEBNFBlock(GrammarAST ebnfRoot, List<CodeBlockForAlt> alts);

tool/src/org/antlr/v4/codegen/SourceGenTriggers.g

@@ -108,7 +108,7 @@ element returns [List<? extends SrcOp> omos]
 	|	subrule							{$omos = $subrule.omos;}
 	|   ACTION							{$omos = controller.action($ACTION);}
 	|   SEMPRED							{$omos = controller.sempred($SEMPRED);}
-	|	treeSpec
+	|	treeSpec						{$omos = DefaultOutputModelFactory.list($treeSpec.treeMatch);}
 	;
 
 labeledElement returns [List<? extends SrcOp> omos]
@@ -118,8 +118,14 @@ labeledElement returns [List<? extends SrcOp> omos]
 	|	^(PLUS_ASSIGN ID block[$ID,null,null])		{$omos = $block.omos;}
 	;
 
-treeSpec returns [SrcOp omo]
-    : ^(TREE_BEGIN  (e=element )+)
+treeSpec returns [MatchTree treeMatch]
+@init {
+   	List<SrcOp> elems = new ArrayList<SrcOp>();
+}
+    :	^(TREE_BEGIN
+       		(e=element {if ($e.omos!=null) elems.addAll($e.omos);})+
+    	 )
+    	{$treeMatch = controller.tree($TREE_BEGIN, elems);}
     ;
 
 subrule returns [List<? extends SrcOp> omos]
@@ -187,6 +193,8 @@ terminal[GrammarAST label, GrammarAST astOp] returns [List<SrcOp> omos]
     |	^(TOKEN_REF ARG_ACTION .)	{$omos = controller.tokenRef($TOKEN_REF, $label, $ARG_ACTION, $astOp);}
     |	^(TOKEN_REF .)				{$omos = controller.tokenRef($TOKEN_REF, $label, null, $astOp);}
     |	TOKEN_REF					{$omos = controller.tokenRef($TOKEN_REF, $label, null, $astOp);}
+    |	DOWN_TOKEN					{$omos = controller.tokenRef($DOWN_TOKEN, null, null, null);}
+    |	UP_TOKEN					{$omos = controller.tokenRef($UP_TOKEN, null, null, null);}
     ;
 
 elementOptions

tool/src/org/antlr/v4/codegen/TreeParserFactory.java

@@ -0,0 +1,57 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.codegen;
+
+import org.antlr.v4.codegen.model.*;
+import org.antlr.v4.tool.GrammarAST;
+
+import java.util.List;
+
+public class TreeParserFactory extends ParserFactory {
+	public TreeParserFactory(CodeGenerator gen) {
+		super(gen);
+	}
+
+	@Override
+	public TreeParserFile treeParserFile(String fileName) {
+		return new TreeParserFile(this, fileName);
+	}
+
+	@Override
+	public TreeParserModel treeParser(TreeParserFile file) {
+		return new TreeParserModel(this, file);
+	}
+
+	@Override
+	public MatchTree tree(GrammarAST treeBeginAST, List<? extends SrcOp> omos) {
+		return new MatchTree(this, treeBeginAST, omos);
+	}
+
+}

tool/src/org/antlr/v4/codegen/TreeParserFile.java

@@ -0,0 +1,38 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.codegen;
+
+import org.antlr.v4.codegen.model.ParserFile;
+
+public class TreeParserFile extends ParserFile {
+	public TreeParserFile(OutputModelFactory factory, String fileName) {
+		super(factory, fileName);
+	}
+}

tool/src/org/antlr/v4/codegen/model/MatchDOWN.java

@@ -0,0 +1,39 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.codegen.model;
+
+import org.antlr.v4.codegen.OutputModelFactory;
+import org.antlr.v4.tool.GrammarAST;
+
+public class MatchDOWN extends RuleElement {
+	public MatchDOWN(OutputModelFactory factory, GrammarAST ast) {
+		super(factory, ast);
+	}
+}

tool/src/org/antlr/v4/codegen/model/MatchTree.java

@@ -0,0 +1,45 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.codegen.model;
+
+import org.antlr.v4.codegen.OutputModelFactory;
+import org.antlr.v4.tool.GrammarAST;
+
+import java.util.List;
+
+public class MatchTree extends RuleElement {
+	@ModelElement public List<? extends SrcOp> elems;
+
+	public MatchTree(OutputModelFactory factory, GrammarAST ast, List<? extends SrcOp> elems) {
+		super(factory, ast);
+		this.elems = elems;
+	}
+
+}

tool/src/org/antlr/v4/codegen/model/MatchUP.java

@@ -0,0 +1,39 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.codegen.model;
+
+import org.antlr.v4.codegen.OutputModelFactory;
+import org.antlr.v4.tool.GrammarAST;
+
+public class MatchUP extends RuleElement {
+	public MatchUP(OutputModelFactory factory, GrammarAST ast) {
+		super(factory, ast);
+	}
+}

tool/src/org/antlr/v4/parse/ANTLRParser.g

@@ -93,6 +93,9 @@ tokens {
     ST_RESULT;			  // distinguish between ST and tree rewrites
     RESULT;
     ALT_REWRITE;		  // indicate ALT is rewritten
+    
+    DOWN_TOKEN;			  // AST node representing DOWN node in tree parser code gen
+    UP_TOKEN;
 }
 
 // Include the copyright in this source and also the generated source
@@ -650,12 +653,17 @@ treeSpec
          // Only a subset of elements are allowed to be a root node. However
          // we allow any element to appear here and reject silly ones later
          // when we walk the AST.
-         element
+         root=element
          // After the tree root we get the usual suspects,
          // all members of the element set
-         element+
+         (kids+=element)+
       RPAREN
-      -> ^(TREE_BEGIN element+)
+      -> ^(TREE_BEGIN
+      		$root
+      		DOWN_TOKEN<DownAST>[$TREE_BEGIN]
+      		$kids+
+     		UP_TOKEN<UpAST>[$TREE_BEGIN]
+   		)
     ;
 
 // A block of gramamr structure optionally followed by standard EBNF

tool/src/org/antlr/v4/parse/ATNBuilder.g

@@ -98,6 +98,8 @@ element returns [ATNFactory.Handle p]
 	|	^(ROOT a=astOperand)		{$p = $a.p;}
 	|	^(BANG a=astOperand)		{$p = $a.p;}
     |	^(NOT b=blockSet[true])		{$p = $b.p;}
+    |	DOWN_TOKEN					{$p = factory.tokenRef((DownAST)$start);}
+    |	UP_TOKEN					{$p = factory.tokenRef((UpAST)$start);}
 	;
 
 astOperand returns [ATNFactory.Handle p]
@@ -112,7 +114,8 @@ labeledElement returns [ATNFactory.Handle p]
 
 treeSpec returns [ATNFactory.Handle p]
 @init {List<ATNFactory.Handle> els = new ArrayList<ATNFactory.Handle>();}
-    : ^(TREE_BEGIN  (e=element {els.add($e.p);})+)	{$p = factory.tree(els);}
+    :	^(TREE_BEGIN (e=element {els.add($e.p);})+ )
+    	{$p = factory.tree($TREE_BEGIN, els);}
     ;
 
 subrule returns [ATNFactory.Handle p]

tool/src/org/antlr/v4/parse/GrammarTreeVisitor.g

@@ -170,6 +170,14 @@ public void rewriteStringRef(TerminalAST ast, GrammarAST options) { }
 public void rewriteRuleRef(GrammarAST ast) { }
 public void rewriteLabelRef(GrammarAST ast) { }
 public void rewriteAction(ActionAST ast) { }
+
+	public void traceIn(String ruleName, int ruleIndex)  {
+		System.err.println("enter "+ruleName+": "+input.LT(1));
+	}
+
+	public void traceOut(String ruleName, int ruleIndex)  {
+		System.err.println("exit "+ruleName+": "+input.LT(1));
+	}
 }
 
 grammarSpec
@@ -363,7 +371,7 @@ labeledElement
 	;
 
 treeSpec
-    : ^(TREE_BEGIN element+)
+    : ^(TREE_BEGIN element DOWN_TOKEN element+ UP_TOKEN )
     ;
 
 subrule

tool/src/org/antlr/v4/tool/DownAST.java

@@ -0,0 +1,49 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.tool;
+
+import org.antlr.runtime.Token;
+
+public class DownAST extends TerminalAST {
+	public DownAST(int type, Token t) {
+		super(type, t);
+	}
+
+
+	@Override
+	public String getText() {
+		return "DOWN";
+	}
+
+	@Override
+	public String toString() {
+		return getText();
+	}
+}

tool/src/org/antlr/v4/tool/GrammarAST.java

@@ -176,11 +176,6 @@ public class GrammarAST extends CommonTree {
 		return (GrammarAST)adaptor.dupTree(t);
 	}
 
-    @Override
-    public String toString() {
-        return super.toString();
-    }
-
 	public String toTokenString() {
 		CharStream input = this.token.getInputStream();
 		GrammarASTAdaptor adaptor = new GrammarASTAdaptor(input);

tool/src/org/antlr/v4/tool/UpAST.java

@@ -0,0 +1,48 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.tool;
+
+import org.antlr.runtime.Token;
+
+public class UpAST extends TerminalAST {
+	public UpAST(int type, Token t) {
+		super(type, t);
+	}
+
+	@Override
+	public String getText() {
+		return "UP";
+	}
+
+	@Override
+	public String toString() {
+		return getText();
+	}
+}

tool/test/org/antlr/v4/test/BaseTest.java

@@ -36,6 +36,7 @@ import org.antlr.v4.runtime.atn.*;
 import org.antlr.v4.runtime.dfa.DFA;
 import org.antlr.v4.semantics.SemanticPipeline;
 import org.antlr.v4.tool.*;
+import org.antlr.v4.tool.Rule;
 import org.junit.*;
 import org.stringtemplate.v4.ST;
 
@@ -737,6 +738,23 @@ public abstract class BaseTest {
 		return filtered;
 	}
 
+	void checkRuleATN(Grammar g, String ruleName, String expecting) {
+		ParserATNFactory f = new ParserATNFactory(g);
+		if ( g.isTreeGrammar() ) f = new TreeParserATNFactory(g);
+		ATN atn = f.createATN();
+
+		DOTGenerator dot = new DOTGenerator(g);
+		System.out.println(dot.getDOT(atn.ruleToStartState[g.getRule(ruleName).index]));
+
+		Rule r = g.getRule(ruleName);
+		ATNState startState = atn.ruleToStartState[r.index];
+		ATNPrinter serializer = new ATNPrinter(g, startState);
+		String result = serializer.asString();
+
+		//System.out.print(result);
+		assertEquals(expecting, result);
+	}
+
 	public static class StreamVacuum implements Runnable {
 		StringBuffer buf = new StringBuffer();
 		BufferedReader in;

tool/test/org/antlr/v4/test/TestATNConstruction.java

@@ -16,7 +16,7 @@ public class TestATNConstruction extends BaseTest {
 			"s2-A->s3\n" +
 			"s3->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s4\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAB() throws Exception {
@@ -30,7 +30,7 @@ public class TestATNConstruction extends BaseTest {
 			"s4-B->s5\n" +
 			"s5->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s6\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorB() throws Exception {
@@ -49,7 +49,7 @@ public class TestATNConstruction extends BaseTest {
 			"s6-action_0:-1->s7\n" + // actionIndex -1 since not forced action
 			"RuleStop_a_1-EOF->s10\n" +
 			"s7->BlockEnd_9\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testSetAorB() throws Exception {
@@ -66,7 +66,7 @@ public class TestATNConstruction extends BaseTest {
 			"s5->BlockEnd_7\n" +
 			"BlockEnd_7->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s8\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testLexerIsntSetMultiCharString() throws Exception {
@@ -138,7 +138,7 @@ public class TestATNConstruction extends BaseTest {
 			"s5->BlockEnd_7\n" +
 			"BlockEnd_7->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s8\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testABorCD() throws Exception {
@@ -159,7 +159,7 @@ public class TestATNConstruction extends BaseTest {
 			"s9->BlockEnd_11\n" +
 			"BlockEnd_11->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s12\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testbA() throws Exception {
@@ -174,13 +174,13 @@ public class TestATNConstruction extends BaseTest {
 			"s6-A->s7\n" +
 			"s7->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s10\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 		expecting =
 			"RuleStart_b_2->s8\n" +
 			"s8-B->s9\n" +
 			"s9->RuleStop_b_3\n" +
 			"RuleStop_b_3->s5\n";
-		checkRule(g, "b", expecting);
+		checkRuleATN(g, "b", expecting);
 	}
 
 	@Test public void testFollow() throws Exception {
@@ -195,7 +195,7 @@ public class TestATNConstruction extends BaseTest {
 			"s11->RuleStop_b_3\n" +
 			"RuleStop_b_3->s7\n" +
 			"RuleStop_b_3->s13\n";
-		checkRule(g, "b", expecting);
+		checkRuleATN(g, "b", expecting);
 	}
 
 	@Test public void testAorEpsilon() throws Exception {
@@ -212,7 +212,7 @@ public class TestATNConstruction extends BaseTest {
 			"s5->BlockEnd_7\n" +
 			"BlockEnd_7->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s8\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAOptional() throws Exception {
@@ -227,7 +227,7 @@ public class TestATNConstruction extends BaseTest {
 			"BlockEnd_5->RuleStop_a_1\n" +
 			"s3->BlockEnd_5\n" +
 			"RuleStop_a_1-EOF->s6\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorBoptional() throws Exception {
@@ -247,7 +247,7 @@ public class TestATNConstruction extends BaseTest {
 			"RuleStop_a_1-EOF->s10\n" +
 			"s4-action_0:-1->s5\n" +
 			"s5->BlockEnd_9\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testSetAorBoptional() throws Exception {
@@ -262,7 +262,7 @@ public class TestATNConstruction extends BaseTest {
 			"BlockEnd_5->RuleStop_a_1\n" +
 			"s3->BlockEnd_5\n" +
 			"RuleStop_a_1-EOF->s6\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorBthenC() throws Exception {
@@ -276,7 +276,7 @@ public class TestATNConstruction extends BaseTest {
 			"s4-C->s5\n" +
 			"s5->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s6\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAplus() throws Exception {
@@ -293,7 +293,7 @@ public class TestATNConstruction extends BaseTest {
 			"PlusLoopBack_6->s7\n" +
 			"s7->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s8\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorBplus() throws Exception {
@@ -315,7 +315,7 @@ public class TestATNConstruction extends BaseTest {
 			"s7->BlockEnd_9\n" +
 			"s11->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s12\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorBorEmptyPlus() throws Exception {
@@ -338,7 +338,7 @@ public class TestATNConstruction extends BaseTest {
 			"PlusLoopBack_10->s11\n" +
 			"s11->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s12\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAStar() throws Exception {
@@ -356,7 +356,7 @@ public class TestATNConstruction extends BaseTest {
 			"s3->BlockEnd_5\n" +
 			"BlockEnd_5->StarLoopBack_8\n" +
 			"StarLoopBack_8->StarLoopEntry_6\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testNestedAstar() throws Exception {
@@ -382,7 +382,7 @@ public class TestATNConstruction extends BaseTest {
 			"StarLoopBack_15->StarLoopEntry_13\n" +
 			"BlockEnd_7->StarLoopBack_10\n" +
 			"StarLoopBack_10->StarLoopEntry_8\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testAorBstar() throws Exception {
@@ -405,7 +405,7 @@ public class TestATNConstruction extends BaseTest {
 			"s6-action_0:-1->s7\n" +
 			"StarLoopBack_12->StarLoopEntry_10\n" +
 			"s7->BlockEnd_9\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 	@Test public void testPredicatedAorB() throws Exception {
@@ -426,7 +426,7 @@ public class TestATNConstruction extends BaseTest {
 			"s9->BlockEnd_11\n" +
 			"BlockEnd_11->RuleStop_a_1\n" +
 			"RuleStop_a_1-EOF->s12\n";
-		checkRule(g, "a", expecting);
+		checkRuleATN(g, "a", expecting);
 	}
 
 /*
@@ -978,19 +978,4 @@ public class TestATNConstruction extends BaseTest {
 		assertEquals(expecting, result);
 	}
 
-	void checkRule(Grammar g, String ruleName, String expecting) {
-		ParserATNFactory f = new ParserATNFactory(g);
-		ATN atn = f.createATN();
-
-		DOTGenerator dot = new DOTGenerator(g);
-		System.out.println(dot.getDOT(atn.ruleToStartState[g.getRule(ruleName).index]));
-
-		Rule r = g.getRule(ruleName);
-		ATNState startState = atn.ruleToStartState[r.index];
-		ATNPrinter serializer = new ATNPrinter(g, startState);
-		String result = serializer.asString();
-
-		//System.out.print(result);
-		assertEquals(expecting, result);
-	}
 }

tool/test/org/antlr/v4/test/TestATNTreeGrammarConstruction.java

@@ -0,0 +1,68 @@
+/*
+ [The "BSD license"]
+ Copyright (c) 2011 Terence Parr
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+
+ 1. Redistributions of source code must retain the above copyright
+    notice, this list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ 3. The name of the author may not be used to endorse or promote products
+    derived from this software without specific prior written permission.
+
+ THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package org.antlr.v4.test;
+
+import org.antlr.v4.tool.Grammar;
+import org.junit.Test;
+
+public class TestATNTreeGrammarConstruction extends BaseTest {
+	@Test public void testAB() throws Exception {
+		Grammar g = new Grammar(
+			"tree grammar P;\n"+
+			"a : A B ;");
+		String expecting =
+			"RuleStart_a_0->s2\n" +
+			"s2-A->s3\n" +
+			"s3->s4\n" +
+			"s4-B->s5\n" +
+			"s5->RuleStop_a_1\n" +
+			"RuleStop_a_1-EOF->s6\n";
+		checkRuleATN(g, "a", expecting);
+	}
+
+	@Test public void testTreeAB() throws Exception {
+		Grammar g = new Grammar(
+			"tree grammar P;\n"+
+			"a : ^(A B) ;");
+		String expecting =
+			"RuleStart_a_0->s2\n" +
+			"s2-A->s3\n" +
+			"s3->s4\n" +
+			"s4-DOWN->s5\n" +
+			"s5->s6\n" +
+			"s6-B->s7\n" +
+			"s7->s8\n" +
+			"s8-UP->s9\n" +
+			"s9->RuleStop_a_1\n" +
+			"RuleStop_a_1-EOF->s10\n";
+		checkRuleATN(g, "a", expecting);
+	}
+
+}