working on parse trees

[git-p4: depot-paths = "//depot/code/antlr4/main/": change = 9036]

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

@@ -80,18 +80,26 @@ public class Parser extends BaseRecognizer {
 	}
 
     public TokenStream getTokenStream() {
-		return (TokenStream)input;
+		return input;
 	}
 
 	public String getSourceName() {
 		return input.getSourceName();
 	}
 
-	public void traceIn(int ruleIndex, ParserRuleContext ctx)  {
-		super.traceIn(getRuleNames()[ruleIndex], ruleIndex, input.LT(1));
-	}
+	/** Always called by generated parsers upon entry to a rule.
+	 *  This occurs after the new context has been pushed. Access field
+	 *  _ctx get the current context.
+	 *
+	 *  The HotSpot compiler should optimize/inline these empty methods
+	 *  so there is no overhead to always having the parser call them.
+	 *  It is also much more flexible because users do not have to
+	 *  regenerate parsers to get trace facilities.
+	 *
+	 *  These methods along with an override of match() are used to build
+	 *  parse trees as well.
+	 */
+	public void enterRule(int ruleIndex) { }
 
-	public void traceOut(int ruleIndex, ParserRuleContext ctx)  {
-		super.traceOut(getRuleNames()[ruleIndex], ruleIndex, input.LT(1));
-	}
+	public void exitRule(int ruleIndex) { }
 }

runtime/Java/src/org/antlr/v4/runtime/debug/Tracer.java

@@ -42,19 +42,21 @@ public class Tracer extends BlankDebugEventListener {
 		this.input = input;
 	}
 
-	public void enterRule(String ruleName) {
+	@Override
+	public void enterRule(String grammarFileName, String ruleName) {
 		for (int i=1; i<=level; i++) {System.out.print(" ");}
 		System.out.println("> "+ruleName+" lookahead(1)="+getInputSymbol(1));
 		level++;
 	}
 
-	public void exitRule(String ruleName) {
+	@Override
+	public void exitRule(String grammarFileName, String ruleName) {
 		level--;
 		for (int i=1; i<=level; i++) {System.out.print(" ");}
 		System.out.println("< "+ruleName+" lookahead(1)="+getInputSymbol(1));
 	}
 
-	public Object getInputSymbol(int k) {
+	protected Object getInputSymbol(int k) {
 		if ( input instanceof TokenStream) {
 			return ((TokenStream)input).LT(k);
 		}

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

@@ -27,63 +27,61 @@
  */
 package org.antlr.v4.runtime.tree;
 
+import org.antlr.v4.runtime.RuleContext;
 import org.antlr.v4.runtime.Token;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /** A record of the rules used to match a token sequence.  The tokens
  *  end up as the leaves of this tree and rule nodes are the interior nodes.
- *  This really adds no functionality, it is just an alias for CommonTree
- *  that is more meaningful (specific) and holds a String to display for a node.
  */
-public class ParseTree extends BaseTree {
-	public Object payload;
-	public List hiddenTokens;
+public abstract class ParseTree {
 
-	public ParseTree(Object label) {
-		this.payload = label;
-	}
-
-	public Tree dupNode() {
-		return null;
-	}
-
-	public int getType() {
-		return 0;
-	}
-
-	public String getText() {
-		return toString();
-	}
-
-	public int getTokenStartIndex() {
-		return 0;
-	}
-
-	public void setTokenStartIndex(int index) {
-	}
-
-	public int getTokenStopIndex() {
-		return 0;
-	}
-
-	public void setTokenStopIndex(int index) {
-	}
-
-	public String toString() {
-		if ( payload instanceof Token ) {
-			Token t = (Token)payload;
-			if ( t.getType() == Token.EOF ) {
-				return "<EOF>";
-			}
-			return t.getText();
+	public static class TokenNode extends ParseTree {
+		public Token token;
+		public TokenNode(Token token) {
+			this.token = token;
+		}
+
+		@Override
+		public String toString() {
+			if ( token.getType() == Token.EOF ) return "<EOF>";
+			return token.getText();
 		}
-		return payload.toString();
 	}
 
-	/** Emit a token and all hidden nodes before.  EOF node holds all
-	 *  hidden tokens after last real token.
-	 */
+	public static class RuleNode extends ParseTree {
+		public RuleContext ctx;
+		public String ruleName;
+		public RuleNode(String ruleName, RuleContext ctx) {
+			this.ruleName = ruleName;
+			this.ctx = ctx;
+		}
+		public String toString() { return ruleName; }
+	}
+
+	protected ParseTree parent;
+	protected List<ParseTree> children;
+	protected List hiddenTokens;
+
+	/** Add t as child of this node.  t must not be nil node. */
+	public void addChild(ParseTree t) {
+		if ( children==null ) children = new ArrayList<ParseTree>();
+		children.add(t);
+	}
+
+	public ParseTree getChild(int i) {
+		if ( children==null || i>=children.size() ) {
+			return null;
+		}
+		return children.get(i);
+	}
+
+	public ParseTree getParent() { return parent; }
+
+	public void setParent(ParseTree t) { parent = t; }
+
 	public String toStringWithHiddenTokens() {
 		StringBuffer buf = new StringBuffer();
 		if ( hiddenTokens!=null ) {
@@ -106,13 +104,13 @@ public class ParseTree extends BaseTree {
 		return buf.toString();
 	}
 
-	public void _toStringLeaves(StringBuffer buf) {
-		if ( payload instanceof Token ) { // leaf node token?
+	protected void _toStringLeaves(StringBuffer buf) {
+		if ( children==null ) { // leaf node token?
 			buf.append(this.toStringWithHiddenTokens());
 			return;
 		}
 		for (int i = 0; children!=null && i < children.size(); i++) {
-			ParseTree t = (ParseTree)children.get(i);
+			ParseTree t = children.get(i);
 			t._toStringLeaves(buf);
 		}
 	}

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

@@ -128,8 +128,9 @@ public QStack\<<currentRule.ctxType>\> <currentRule.name>_stk = new QStack\<<cur
 
 <if(currentRule.modifiers)><currentRule.modifiers:{f | <f> }><else>public final <endif><currentRule.ctxType> <currentRule.name>(<currentRule.args; separator=",">) throws RecognitionException {
     <currentRule.ctxType> _localctx = new <currentRule.ctxType>(_ctx, <currentRule.startState><currentRule.args:{a | , <a.name>}>);
-    _ctx = _localctx;
     <currentRule.name>_stk.push(_localctx);
+    _ctx = _localctx;
+    enterRule(<currentRule.index>);
     _localctx.start = input.LT(1);
     //System.out.println("enter "+ruleNames[<currentRule.index>]+", LT(1)="+input.LT(1).getText());
     <namedActions.init>
@@ -148,6 +149,7 @@ public QStack\<<currentRule.ctxType>\> <currentRule.name>_stk = new QStack\<<cur
         <currentRule.name>_stk.pop();
         _ctx = (ParserRuleContext)_ctx.parent;
         <finallyAction>
+        exitRule(<currentRule.index>);
     	// System.out.println("exit "+ruleNames[<currentRule.index>]);
 	}
     return _localctx;