got AST construction ops working it seems.

[git-p4: depot-paths = "//depot/code/antlr4/main/": change = 8797]

runtime/Java/src/org/antlr/v4/runtime/CommonToken.java

@@ -100,13 +100,12 @@ public class CommonToken implements Token, Serializable {
 		if ( input==null ) {
 			return null;
 		}
-        if ( start<input.size() && stop<input.size() ) {
-		    text = input.substring(start,stop);
-        }
-        else {
-            text = "<EOF>";
-        }
-		return text;
+		if ( start<input.size() && stop<input.size() ) {
+			return input.substring(start,stop);
+		}
+		else {
+			return "<EOF>";
+		}
 	}
 
 	/** Override the text for this token.  getText() will return this text

runtime/Java/src/org/antlr/v4/runtime/Parser.java

@@ -28,14 +28,14 @@
 package org.antlr.v4.runtime;
 
 
-import org.antlr.v4.runtime.tree.TreeAdaptor;
+import org.antlr.v4.runtime.tree.*;
 
 /** A parser for TokenStreams.  "parser grammars" result in a subclass
  *  of this.
  */
 public class Parser extends BaseRecognizer {
 
-	public TreeAdaptor _adaptor;
+	public TreeAdaptor _adaptor = new CommonTreeAdaptor();
 
 	public Parser(TokenStream input) {
 		super(input);

runtime/Java/src/org/antlr/v4/runtime/tree/BaseTree.java

@@ -27,8 +27,7 @@
  */
 package org.antlr.v4.runtime.tree;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.*;
 
 /** A generic tree implementation with no payload.  You must subclass to
  *  actually have any user data.  ANTLR v3 uses a list of children approach
@@ -130,6 +129,7 @@ public abstract class BaseTree implements Tree {
 
 	/** Add all elements of kids list as children of this node */
 	public void addChildren(List kids) {
+		if ( kids==null ) return;
 		for (int i = 0; i < kids.size(); i++) {
 			Tree t = (Tree) kids.get(i);
 			addChild(t);

runtime/Java/src/org/antlr/v4/runtime/tree/BaseTreeAdaptor.java

@@ -42,27 +42,34 @@ public abstract class BaseTreeAdaptor implements TreeAdaptor {
 
 	// BEGIN v4 stuff
 
-	public Object becomeRoot(Object newRoot, Object oldRoot, List kids) {
+	public Object becomeRoot(Object oldRoot, Object newRoot, List kids) {
 		return null;
 	}
 
-	/** if oldRoot is null then:
-	 * 		create root for rootToken using kids.
+	/** if oldRoot is nil then:
+	 * 		create newRoot for rootToken
+	 *  	add kids to newRoot
+	 *   	clear kids
 	 *  	return as new root
-	 *  if oldRoot not null then:
+	 *  if oldRoot not nil then:
 	 *  	add kids to oldRoot
 	 *  	clear kids
-	 *  	create rootToken using kids
+	 *  	create rootToken
 	 *  	return as new root
 	 */
-	public Object becomeRoot(Object newRoot, Token rootToken, List kids) {
-		if ( newRoot==null ) {
-			newRoot = create(rootToken);
-			addChildren(newRoot, kids);
+	public Object becomeRoot(Object oldRoot, Token rootToken, List kids) {
+		// first flush all previous children onto old root
+		if ( ((Tree)oldRoot).isNil() ) {
+			oldRoot = create(rootToken);
+			addChildren(oldRoot, kids);
 			kids.clear();
-			return newRoot;
+			return oldRoot;
 		}
-		return null;
+		addChildren(oldRoot, kids);
+		kids.clear();
+		Object newRoot = create(rootToken);
+		addChild(newRoot, oldRoot); // newRoot becomes root of old root
+		return newRoot;
 	}
 
 	public void addChildren(Object root, List kids) {

runtime/Java/src/org/antlr/v4/runtime/tree/TreeAdaptor.java

@@ -45,18 +45,20 @@ public interface TreeAdaptor {
 	// x^
 	public Object becomeRoot(Object oldRoot, Object newRoot, List kids);
 
-	/** if oldRoot is null then:
-	 * 		create root for rootToken using kids.
+	/** if oldRoot is nil then:
+	 * 		create newRoot for rootToken
+	 *  	add kids to newRoot
+	 *   	clear kids
 	 *  	return as new root
-	 *  if oldRoot not null then:
+	 *  if oldRoot not nil then:
 	 *  	add kids to oldRoot
 	 *  	clear kids
-	 *  	create rootToken using kids
+	 *  	create rootToken
 	 *  	return as new root
 	 */
 	public Object becomeRoot(Object oldRoot, Token rootToken, List kids);
 
-	// end of outer rule block, set return value
+	// If not null root, add kids to it
 	public void addChildren(Object root, List kids);
 
 	// END new v4 stuff

tool/playground/T.g

@@ -1,11 +1,13 @@
 grammar T;
 options {output=AST;}
-a : x+=A^ y+=b B! B b!;
+a : A^ C^ D ;
 
 b : B ;
 
 A : 'a';
 B : 'b';
+C : 'c';
+D : 'd';
 WS : ' '|'\t'|'\n' {skip();} ;
 
 /*

tool/playground/TestT.java

@@ -2,6 +2,7 @@ import org.antlr.v4.Tool;
 import org.antlr.v4.automata.ParserATNFactory;
 import org.antlr.v4.runtime.*;
 import org.antlr.v4.runtime.atn.ATN;
+import org.antlr.v4.runtime.tree.Tree;
 import org.antlr.v4.semantics.SemanticPipeline;
 import org.antlr.v4.tool.*;
 
@@ -9,8 +10,11 @@ import java.util.List;
 
 public class TestT {
 	public static void main(String[] args) throws Exception {
-//		TLexer t = new TLexer(new ANTLRFileStream(args[0]));
-//		CommonTokenStream tokens = new CommonTokenStream(t);
+		TLexer t = new TLexer(new ANTLRFileStream(args[0]));
+		CommonTokenStream tokens = new CommonTokenStream(t);
+		TParser p = new TParser(tokens);
+		ParserRuleContext ret = p.a();
+		System.out.println(((Tree)ret.tree).toStringTree());
 	}
 
 	public static void dump() throws Exception {

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

@@ -365,8 +365,10 @@ KidsListName(level) ::= "_kids<level>"
 
 AddTokenLeaf(a) ::= "_kids0.add(_adaptor.create(<labelref(a.label)>));"
 AddRuleLeaf(a) ::= "_kids0.add(<labelref(a.label)>.tree);"
-BecomeRoot(r) ::= "_root0 = _root0==null ? <labelref(r.label)> : _adaptor.becomeRoot(_root0, <labelref(r.label)>, _kids0);"
+// TODO: need RuleBecomeRoot
+BecomeRoot(r) ::= "_root0 = _root0==null ? _adaptor.create(<labelref(r.label)>) : _adaptor.becomeRoot(_root0, <labelref(r.label)>, _kids0);"
 AssignTreeResult(a) ::= <<
+if ( _root0==null && _kids0.size()>0 ) _root0 = _adaptor.nil();
 _adaptor.addChildren(_root0, _kids0);
 _localctx.tree = _root0;
 >>