reworked look comp for loops

[git-p4: depot-paths = "//depot/code/antlr4/main/": change = 6884]

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

@@ -1,7 +1,9 @@
 package org.antlr.v4.automata;
 
-/** */
+/** Start of (A|B|...)+ loop. Not decision, inner block has decision state */
-public class PlusBlockStartState extends BlockStartState {
+public class PlusBlockStartState extends BasicState {
 	public LoopbackState loopBackState;
+	public BlockEndState endState;
+	
 	public PlusBlockStartState(NFA nfa) { super(nfa); }
 }

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

@@ -1,7 +1,6 @@
 package org.antlr.v4.codegen.src;
 
 import org.antlr.v4.analysis.LinearApproximator;
-import org.antlr.v4.automata.BlockStartState;
 import org.antlr.v4.automata.NFAState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
@@ -22,7 +21,6 @@ public abstract class Choice extends SrcOp {
 	public Choice(OutputModelFactory factory, GrammarAST blkOrEbnfRootAST, List<CodeBlock> alts) {
 		super(factory, blkOrEbnfRootAST);
 		this.alts = alts;
-		this.decision = ((BlockStartState)blkOrEbnfRootAST.nfaState).decision;
 
 		// TODO: use existing lookahead! don't compute
 		LinearApproximator approx = new LinearApproximator(factory.g, decision);
@@ -30,7 +28,7 @@ public abstract class Choice extends SrcOp {
 		expecting = approx.LOOK(decisionState);
 		System.out.println(blkOrEbnfRootAST.toStringTree()+" loop expecting="+expecting);
 
-		this.error = new ThrowNoViableAlt(factory, blkOrEbnfRootAST, expecting); 
+//		this.error = new ThrowNoViableAlt(factory, blkOrEbnfRootAST, expecting); 
 		this.sync = new Sync(factory, blkOrEbnfRootAST, expecting);
 	}
 

tool/src/org/antlr/v4/codegen/src/LL1Choice.java

@@ -2,6 +2,7 @@ package org.antlr.v4.codegen.src;
 
 import org.antlr.v4.analysis.LinearApproximator;
 import org.antlr.v4.automata.DFA;
+import org.antlr.v4.automata.DecisionState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
@@ -18,6 +19,7 @@ public class LL1Choice extends Choice {
 	
 	public LL1Choice(OutputModelFactory factory, GrammarAST blkAST, List<CodeBlock> alts) {
 		super(factory, blkAST, alts);
+		this.decision = ((DecisionState)blkAST.nfaState).decision;
 		DFA dfa = factory.g.decisionDFAs.get(decision);
 		altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
 		altLook = new ArrayList<String[]>();

tool/src/org/antlr/v4/codegen/src/LL1Loop.java

@@ -8,7 +8,7 @@ import java.util.ArrayList;
 import java.util.List;
 
 /** */
-public abstract class LL1Loop extends LL1Choice {
+public abstract class LL1Loop extends Choice {
 	public OutputModelObject expr;
 	public List<SrcOp> iteration;
 

tool/src/org/antlr/v4/codegen/src/LL1PlusBlock.java

@@ -1,15 +1,23 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.analysis.LinearApproximator;
+import org.antlr.v4.automata.BlockStartState;
 import org.antlr.v4.automata.DFA;
 import org.antlr.v4.automata.PlusBlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** */
 public class LL1PlusBlock extends LL1Loop {
+	/** Token names for each alt 0..n-1 */
+	public List<String[]> altLook;
+	/** Lookahead for each alt 1..n */
+	public IntervalSet[] altLookSets;
+	
 	public String loopLabel;
 	public String loopCounterVar;
 	public String[] exitLook;
@@ -17,11 +25,19 @@ public class LL1PlusBlock extends LL1Loop {
 
 	public LL1PlusBlock(OutputModelFactory factory, GrammarAST blkAST, List<CodeBlock> alts) {
 		super(factory, blkAST, alts);
-		PlusBlockStartState plusStart = (PlusBlockStartState)blkAST.nfaState;
+		PlusBlockStartState plus = (PlusBlockStartState)blkAST.nfaState;
-		int enterExitDecision = plusStart.decision;
+		BlockStartState blkStart = (BlockStartState)plus.transition(0).target;
 
-		DFA dfa = factory.g.decisionDFAs.get(enterExitDecision);
+		DFA dfa = factory.g.decisionDFAs.get(blkStart.decision);
-		IntervalSet exitLook = dfa.startState.edge(1).label;
+		altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
+		altLook = new ArrayList<String[]>();
+		for (int a=1; a<altLookSets.length; a++) {
+			IntervalSet s = altLookSets[a];
+			altLook.add(factory.gen.target.getTokenTypesAsTargetLabels(factory.g, s.toArray()));
+		}
+
+		dfa = factory.g.decisionDFAs.get(plus.loopBackState.decision);
+		IntervalSet exitLook = dfa.startState.edge(0).label;
 		this.exitLook = factory.gen.target.getTokenTypesAsTargetLabels(factory.g, exitLook.toArray());
 
 		loopLabel = factory.gen.target.getLoopLabel(blkAST);

tool/src/org/antlr/v4/codegen/src/LL1PlusBlockSingleAlt.java

@@ -1,5 +1,8 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.analysis.LinearApproximator;
+import org.antlr.v4.automata.DFA;
+import org.antlr.v4.automata.PlusBlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
@@ -9,17 +12,14 @@ import java.util.List;
 /** */
 public class LL1PlusBlockSingleAlt extends LL1Loop {
 	public ThrowEarlyExitException earlyExitError;
+
 	public LL1PlusBlockSingleAlt(OutputModelFactory factory, GrammarAST blkAST, List<CodeBlock> alts) {
 		super(factory, blkAST, alts);
+		PlusBlockStartState plus = (PlusBlockStartState)blkAST.nfaState;
+		DFA dfa = factory.g.decisionDFAs.get(plus.loopBackState.decision);
+		IntervalSet[] altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
 		IntervalSet loopBackLook = altLookSets[2]; // loop exit is alt 1
 		addCodeForLookaheadTempVar(loopBackLook);
+		this.earlyExitError = new ThrowEarlyExitException(factory, blkAST, expecting);
 	}
-//	@Override
-//	public List<String> getChildren() {
-//		final List<String> sup = super.getChildren();
-//		return new ArrayList<String>() {{
-//			if ( sup!=null ) addAll(sup); add("earlyExitError");
-//		}};
-//	}
-
 }

tool/src/org/antlr/v4/codegen/src/LL1StarBlock.java

@@ -1,27 +1,42 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.analysis.LinearApproximator;
+import org.antlr.v4.automata.BlockStartState;
 import org.antlr.v4.automata.DFA;
 import org.antlr.v4.automata.StarBlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** */
 public class LL1StarBlock extends LL1Loop {
+	/** Token names for each alt 0..n-1 */
+	public List<String[]> altLook;
+	/** Lookahead for each alt 1..n */
+	public IntervalSet[] altLookSets;
+	
 	public String loopLabel;
 	public String[] exitLook;
 	public LL1StarBlock(OutputModelFactory factory, GrammarAST blkAST, List<CodeBlock> alts) {
 		// point at choice block inside outermost enter-exit choice
 		super(factory, ((StarBlockStartState)blkAST.nfaState).transition(0).target.ast, alts);
-		StarBlockStartState starStart = (StarBlockStartState)blkAST.nfaState;
+		StarBlockStartState star = (StarBlockStartState)blkAST.nfaState;
-		int enterExitDecision = starStart.decision;
+		int enterExitDecision = star.decision;
-//		BlockStartState blkStart = (BlockStartState)starStart.transition(0).target;
+		BlockStartState blkStart = (BlockStartState)star.transition(0).target;
-//		this.decision = blkStart.decision;
+		//this.decision = blkStart.decision;
-		int loopbackDecision = starStart.loopBackState.decision;
 
-		DFA dfa = factory.g.decisionDFAs.get(enterExitDecision);
+		DFA dfa = factory.g.decisionDFAs.get(blkStart.decision);
+		altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
+		altLook = new ArrayList<String[]>();
+		for (int a=1; a<altLookSets.length; a++) {
+			IntervalSet s = altLookSets[a];
+			altLook.add(factory.gen.target.getTokenTypesAsTargetLabels(factory.g, s.toArray()));
+		}
+
+		dfa = factory.g.decisionDFAs.get(enterExitDecision);
 		IntervalSet exitLook = dfa.startState.edge(1).label;
 		this.exitLook = factory.gen.target.getTokenTypesAsTargetLabels(factory.g, exitLook.toArray());
 

tool/src/org/antlr/v4/codegen/src/LL1StarBlockSingleAlt.java

@@ -1,5 +1,8 @@
 package org.antlr.v4.codegen.src;
 
+import org.antlr.v4.analysis.LinearApproximator;
+import org.antlr.v4.automata.DFA;
+import org.antlr.v4.automata.StarBlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
@@ -10,6 +13,9 @@ import java.util.List;
 public class LL1StarBlockSingleAlt extends LL1Loop {
 	public LL1StarBlockSingleAlt(OutputModelFactory factory, GrammarAST blkAST, List<CodeBlock> alts) {
 		super(factory, blkAST, alts);
+		StarBlockStartState star = (StarBlockStartState)blkAST.nfaState;
+		DFA dfa = factory.g.decisionDFAs.get(star.loopBackState.decision);
+		IntervalSet[] altLookSets = LinearApproximator.getLL1LookaheadSets(dfa);
 		IntervalSet look = altLookSets[1];
 		addCodeForLookaheadTempVar(look);
 	}

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

@@ -1,6 +1,5 @@
 package org.antlr.v4.codegen.src;
 
-import org.antlr.v4.automata.BlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
@@ -13,7 +12,7 @@ public class Sync extends SrcOp {
 							IntervalSet expecting)
 	{
 		super(factory, blkOrEbnfRootAST);
-		this.decision = ((BlockStartState)blkOrEbnfRootAST.nfaState).decision;
+//		this.decision = ((BlockStartState)blkOrEbnfRootAST.nfaState).decision;
 		this.expecting = factory.createExpectingBitSet(ast, decision, expecting);
 		factory.defineBitSet(this.expecting);
 	}

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

@@ -1,6 +1,5 @@
 package org.antlr.v4.codegen.src;
 
-import org.antlr.v4.automata.BlockStartState;
 import org.antlr.v4.codegen.OutputModelFactory;
 import org.antlr.v4.misc.IntervalSet;
 import org.antlr.v4.tool.GrammarAST;
@@ -15,7 +14,7 @@ public class ThrowRecognitionException extends SrcOp {
 
 	public ThrowRecognitionException(OutputModelFactory factory, GrammarAST ast, IntervalSet expecting) {
 		super(factory, ast);
-		this.decision = ((BlockStartState)ast.nfaState).decision;
+//		this.decision = ((BlockStartState)ast.nfaState).decision;
 		grammarLine = ast.getLine();
 		grammarLine = ast.getCharPositionInLine();
 		grammarFile = factory.g.fileName;