got TestATNInterpreter working

runtime/Java/src/org/antlr/v4/runtime/atn/ATNConfig.java

@@ -170,8 +170,9 @@ public class ATNConfig {
             buf.append(alt);
         }
         if ( context!=null ) {
-            buf.append(",");
+            buf.append(",[");
             buf.append(context.toString(recog));
+			buf.append("]");
         }
         if ( semanticContext!=null && semanticContext != SemanticContext.NONE ) {
             buf.append(",");

runtime/Java/src/org/antlr/v4/runtime/atn/ATNConfigSet.java

@@ -127,9 +127,15 @@ public class ATNConfigSet implements Set<ATNConfig> {
 	public boolean add(ATNConfig value) {
 		Key key = new Key(value);
 		PredictionContext existing = configToContext.get(key);
-		if ( existing==null ) return false;
+		if ( existing==null ) { // nothing there yet; easy, just add
+			configs.add(value);
+			configToContext.put(key, value.context);
+			return true;
+		}
+		// a previous (s,i,pi,_), merge with it and save result
 		PredictionContext merged = PredictionContext.merge(existing, value.context, true);
-		configToContext.put(key, merged);
+		configToContext.put(key, merged); // replace
+		// if already there, must be in configs already
 		return true;
 	}
 
@@ -173,7 +179,7 @@ public class ATNConfigSet implements Set<ATNConfig> {
 	@Override
 	public String toString() {
 		StringBuilder buf = new StringBuilder();
-		buf.append(super.toString());
+		buf.append(configs.toString());
 		if ( hasSemanticContext ) buf.append(",hasSemanticContext="+hasSemanticContext);
 		if ( uniqueAlt!=ATN.INVALID_ALT_NUMBER ) buf.append(",uniqueAlt="+uniqueAlt);
 		if ( conflictingAlts!=null ) buf.append(",conflictingAlts="+conflictingAlts);
@@ -190,7 +196,10 @@ public class ATNConfigSet implements Set<ATNConfig> {
 	}
 
 	@Override
-	public boolean addAll(Collection<? extends ATNConfig> c) {
+	public boolean addAll(Collection<? extends ATNConfig> coll) {
+		for (ATNConfig c : coll) {
+			add(c);
+		}
 		return false;
 	}
 

runtime/Java/src/org/antlr/v4/runtime/atn/ArrayPredictionContext.java

@@ -113,6 +113,13 @@ public class ArrayPredictionContext extends PredictionContext {
 
 	@Override
 	public String toString() {
-		return Arrays.toString(invokingStates);
+		StringBuilder buf = new StringBuilder();
+		buf.append("[");
+		for (int i=0; i< invokingStates.length; i++) {
+			buf.append(invokingStates[i]);
+			buf.append(parents[i].toString());
+		}
+		buf.append("[");
+		return buf.toString();
 	}
 }

runtime/Java/src/org/antlr/v4/runtime/atn/LL1Analyzer.java

@@ -93,7 +93,7 @@ public class LL1Analyzer {
                          @NotNull Set<ATNConfig> lookBusy,
 						 boolean seeThruPreds)
 	{
-		System.out.println("_LOOK("+s.stateNumber+", ctx="+ctx);
+//		System.out.println("_LOOK("+s.stateNumber+", ctx="+ctx);
         ATNConfig c = new ATNConfig(s, 0, ctx);
         if ( !lookBusy.add(c) ) return;
 
@@ -108,7 +108,7 @@ public class LL1Analyzer {
 					ATNState invokingState = atn.states.get(p.invokingState);
 					RuleTransition rt = (RuleTransition)invokingState.transition(0);
 					ATNState retState = rt.followState;
-					System.out.println("popping back to "+retState);
+//					System.out.println("popping back to "+retState);
 					_LOOK(retState, p.parent, look, lookBusy, seeThruPreds);
 				}
 				return;
@@ -135,7 +135,7 @@ public class LL1Analyzer {
 				look.addAll( IntervalSet.of(Token.MIN_USER_TOKEN_TYPE, atn.maxTokenType) );
 			}
 			else {
-				System.out.println("adding "+ t);
+//				System.out.println("adding "+ t);
 				IntervalSet set = t.label();
 				if (set != null) {
 					if (t instanceof NotSetTransition) {

runtime/Java/src/org/antlr/v4/runtime/atn/ParserATNSimulator.java

@@ -239,7 +239,7 @@ import java.util.Set;
  	 *  holds the decision were evaluating
 */
 public class ParserATNSimulator<Symbol extends Token> extends ATNSimulator {
-	public static boolean debug = false;
+	public static boolean debug = true;
 	public static boolean dfa_debug = false;
 	public static boolean retry_debug = false;
 

runtime/Java/src/org/antlr/v4/runtime/atn/PredictionContext.java

@@ -1,6 +1,5 @@
 package org.antlr.v4.runtime.atn;
 
-import org.antlr.v4.runtime.ParserRuleContext;
 import org.antlr.v4.runtime.Recognizer;
 import org.antlr.v4.runtime.RuleContext;
 import org.antlr.v4.runtime.misc.Nullable;
@@ -86,7 +85,8 @@ public abstract class PredictionContext implements Iterable<SingletonPredictionC
 	}
 
 	public String toString(@Nullable Recognizer<?,?> recog) {
-		return toString(recog, ParserRuleContext.EMPTY);
+		return toString();
+//		return toString(recog, ParserRuleContext.EMPTY);
 	}
 
 	// recog null unless ParserRuleContext, in which case we use subclass toString(...)

runtime/Java/src/org/antlr/v4/runtime/atn/SingletonPredictionContext.java

@@ -17,7 +17,7 @@ public class SingletonPredictionContext extends PredictionContext {
 		return new Iterator<SingletonPredictionContext>() {
 			int i = 0;
 			@Override
-			public boolean hasNext() { return i>0; }
+			public boolean hasNext() { return i==0; }
 
 			@Override
 			public SingletonPredictionContext next() { i++; return self; }
@@ -73,6 +73,6 @@ public class SingletonPredictionContext extends PredictionContext {
 
 	@Override
 	public String toString() {
-		return String.valueOf(invokingState);
+		return String.valueOf(invokingState)+" "+parent.toString();
 	}
 }

tool/playground/U.g

@@ -1,13 +1,4 @@
-grammar U;
-s @after {System.out.println($ctx.toStringTree(this));} : e EOF ;
-e : e '.' ID
-  | e '.' 'this'
-  | '-' e
-  | e '*' e
-  | e ('+'|'-') e
-  | INT
-  | ID
-  ;
-ID : 'a'..'z'+ ;
-INT : '0'..'9'+ ;
-WS : (' '|'\n') {skip();} ;
+lexer grammar U;
+A : 'a' ;
+B : 'b' ;
+C : 'c' ;

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

@@ -2,7 +2,6 @@ package org.antlr.v4.test;
 
 import org.antlr.v4.automata.ParserATNFactory;
 import org.antlr.v4.runtime.NoViableAltException;
-import org.antlr.v4.runtime.TokenStream;
 import org.antlr.v4.runtime.atn.ATN;
 import org.antlr.v4.runtime.atn.ATNState;
 import org.antlr.v4.runtime.atn.BlockStartState;
@@ -285,7 +284,8 @@ public class TestATNInterpreter extends BaseTest {
 		ParserATNFactory f = new ParserATNFactory(g);
 		ATN atn = f.createATN();
 
-		TokenStream input = new IntTokenStream(types);
+		IntTokenStream input = new IntTokenStream(types);
+		System.out.println("input="+input.types);
 		ParserInterpreter interp = new ParserInterpreter(g, input);
 		ATNState startState = atn.ruleToStartState[g.getRule("a").index];
 		if ( startState.transition(0).target instanceof BlockStartState ) {