Added visitor gen mechanism, runtime support

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

@@ -28,16 +28,11 @@ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  */
 package org.antlr.v4.runtime;
 
-import org.antlr.v4.runtime.atn.ATN;
-import org.antlr.v4.runtime.atn.ATNState;
-import org.antlr.v4.runtime.misc.NotNull;
-import org.antlr.v4.runtime.misc.Nullable;
-import org.antlr.v4.runtime.tree.ParseTree;
-import org.antlr.v4.runtime.tree.ParseTreeListener;
+import org.antlr.v4.runtime.atn.*;
+import org.antlr.v4.runtime.misc.*;
+import org.antlr.v4.runtime.tree.*;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
+import java.util.*;
 
 /** A rule invocation record for parsing and tree parsing.
  *
@@ -131,10 +126,11 @@ public ParserRuleContext(@Nullable ParserRuleContext<Symbol> parent, int stateNu
 		this(parent, parent!=null ? parent.s : -1 /* invoking state */, stateNumber);
 	}
 
-	// Double dispatch methods
+	// Double dispatch methods for listeners and visitors
 
 	public void enterRule(ParseTreeListener<Symbol> listener) { }
 	public void exitRule(ParseTreeListener<Symbol> listener) { }
+	public <T> T accept(ParseTreeVisitor<? extends T> visitor) { visitor.visitChildren(this); return null; }
 
 	/** Does not set parent link; other add methods do */
 	public void addChild(TerminalNode<Symbol> t) {

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

@@ -0,0 +1,26 @@
+package org.antlr.v4.runtime.tree;
+
+import org.antlr.v4.runtime.ParserRuleContext;
+
+/** T is return type of visit methods. Use T=Void for no return type. */
+public class ParseTreeVisitor<T> {
+	public T visit(ParserRuleContext<?> ctx) {
+		return ctx.accept(this);
+	}
+
+	/** Visit all rule, nonleaf children. Not useful if you are using T as
+	 *  non-Void.  This returns nothing, losing all computations from below.
+	 *  But handy if you are just walking the tree with a visitor and only
+	 *  care about some nodes.  The ParserRuleContext.accept() method
+	 *  walks all children by default; i.e., calls this method.
+	 */
+	public <Symbol> void visitChildren(ParserRuleContext<Symbol> ctx) {
+		for (ParseTree c : ctx.children) {
+			if ( c instanceof ParseTree.RuleNode) {
+				ParseTree.RuleNode r = (ParseTree.RuleNode)c;
+				ParserRuleContext<Symbol> rctx = (ParserRuleContext<Symbol>)r.getRuleContext();
+				visit(rctx);
+			}
+		}
+	}
+}

tool/playground/AVisitor.java

@@ -0,0 +1,10 @@
+import org.antlr.v4.runtime.tree.*;
+import org.antlr.v4.runtime.Token;
+
+public interface AVisitor<T> {
+	T visit(AParser.MultContext ctx);
+	T visit(AParser.ParensContext ctx);
+	T visit(AParser.sContext ctx);
+	T visit(AParser.AddContext ctx);
+	T visit(AParser.IntContext ctx);
+}

tool/playground/TestE.java

@@ -3,7 +3,7 @@
 public class TestE {
     public static void main(String[] args) throws Exception {
         CharStream input = new ANTLRFileStream(args[0]);
-        E lex = new E(input);
+        ELexer lex = new ELexer(input);
         CommonTokenStream tokens = new CommonTokenStream(lex);
         tokens.fill();
         for (Object t : tokens.getTokens()) System.out.println(t);

tool/playground/TestVisitor.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.
+ */
+
+import org.antlr.v4.runtime.*;
+import org.antlr.v4.runtime.tree.ParseTreeVisitor;
+
+public class TestVisitor {
+	public static class MyVisitor extends ABaseVisitor<Integer> implements AVisitor<Integer> {
+		@Override
+		public Integer visit(AParser.AddContext ctx) {
+			return ctx.e(0).accept(this) + ctx.e(1).accept(this);
+		}
+
+		@Override
+		public Integer visit(AParser.IntContext ctx) {
+			return Integer.valueOf(ctx.INT().getText());
+		}
+
+		@Override
+		public Integer visit(AParser.MultContext ctx) {
+//			return ctx.e(0).accept(this) * ctx.e(1).accept(this);
+			return visit(ctx.e(0)) * visit(ctx.e(1));
+		}
+
+		@Override
+		public Integer visit(AParser.ParensContext ctx) {
+			return ctx.e().accept(this);
+		}
+
+		@Override
+		public Integer visit(AParser.sContext ctx) {
+			return visit(ctx.e());
+			//return ctx.e().accept(this);
+		}
+	}
+
+	public static void main(String[] args) throws Exception {
+		ALexer lexer = new ALexer(new ANTLRFileStream(args[0]));
+		CommonTokenStream tokens = new CommonTokenStream(lexer);
+		AParser p = new AParser(tokens);
+		p.setBuildParseTree(true);
+		ParserRuleContext<Token> t = p.s();
+		System.out.println("tree = "+t.toStringTree(p));
+
+		MyVisitor visitor = new MyVisitor();
+		Integer result = visitor.visit(t);
+//		Integer result = t.accept(visitor);
+		System.out.println("result from tree walk = " + result);
+	}
+}

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

@@ -56,6 +56,28 @@ public class <file.grammarName>BaseListener implements <file.grammarName>Listene
 }
 >>
 
+VisitorFile(file, header) ::= <<
+<header>
+import org.antlr.v4.runtime.tree.*;
+import org.antlr.v4.runtime.Token;
+
+public interface <file.grammarName>Visitor\<T> {
+	<file.visitorNames:{lname |
+T visit(<file.parserName>.<lname>Context ctx);}; separator="\n">
+}
+>>
+
+BaseVisitorFile(file, header) ::= <<
+<header>
+import org.antlr.v4.runtime.tree.*;
+import org.antlr.v4.runtime.Token;
+
+public class <file.grammarName>BaseVisitor\<T> extends ParseTreeVisitor\<T> implements <file.grammarName>Visitor\<T> {
+	<file.visitorNames:{lname |
+public T visit(<file.parserName>.<lname>Context ctx) { visitChildren(ctx); return null; \}}; separator="\n">
+}
+>>
+
 Parser(parser, funcs, atn, sempredFuncs, superclass) ::= <<
 <Parser_(ctor="parser_ctor", ...)>
 >>
@@ -533,7 +555,7 @@ ListLabelName(label)		  ::= "<label>"
 CaptureNextToken(d) ::= "<d.varName> = _input.LT(1);"
 CaptureNextTokenType(d) ::= "<d.varName> = _input.LA(1);"
 
-StructDecl(s,attrs,getters,visitorDispatchMethods,interfaces,extensionMembers,
+StructDecl(s,attrs,getters,dispatchMethods,interfaces,extensionMembers,
            superClass={ParserRuleContext\<<InputSymbolType()>>}) ::= <<
 public static class <s.name> extends <superClass><if(interfaces)> implements <interfaces; separator=", "><endif> {
 	<attrs:{a | <a>}; separator="\n">
@@ -550,27 +572,35 @@ public static class <s.name> extends <superClass><if(interfaces)> implements <in
 		<s.attrs:{a | this.<a.name> = ctx.<a.name>;}; separator="\n">
 	}
 <endif>
-	<visitorDispatchMethods; separator="\n">
+	<dispatchMethods; separator="\n">
 	<extensionMembers; separator="\n">
 }
 >>
 
-AltLabelStructDecl(s,attrs,getters,visitorDispatchMethods) ::= <<
+AltLabelStructDecl(s,attrs,getters,dispatchMethods) ::= <<
 public static class <s.name> extends <currentRule.name>Context {
 	<attrs:{a | <a>}; separator="\n">
 	<getters:{g | <g>}; separator="\n">
 	public <s.name>(<currentRule.name>Context ctx) { copyFrom(ctx); }
-	<visitorDispatchMethods; separator="\n">
+	<dispatchMethods; separator="\n">
 }
 >>
 
-VisitorDispatchMethod(method) ::= <<
+ListenerDispatchMethod(method) ::= <<
 @Override
 public void <if(method.isEnter)>enter<else>exit<endif>Rule(ParseTreeListener\<<InputSymbolType()>\> listener) {
 	if ( listener instanceof <parser.grammarName>Listener ) ((<parser.grammarName>Listener)listener).<if(method.isEnter)>enter<else>exit<endif>(this);
 }
 >>
 
+VisitorDispatchMethod(method) ::= <<
+@Override
+public \<T> T accept(ParseTreeVisitor\<? extends T> visitor) { 
+    if ( visitor instanceof <parser.grammarName>Visitor ) return ((<parser.grammarName>Visitor\<T>)visitor).visit(this);
+    else return null;
+}
+>>
+
 AttributeDecl(d) ::= "public <d.decl>;"
 
 /** If we don't know location of label def x, use this template */

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

@@ -186,8 +186,10 @@ protected void handleArgs() {
 				grammarFiles.add(arg);
 				continue;
 			}
+			boolean found = false;
 			for (Option o : optionDefs) {
 				if ( arg.equals(o.name) ) {
+					found = true;
 					String argValue = null;
 					if ( o.argType==OptionArgType.STRING ) {
 						argValue = args[i];
@@ -198,7 +200,7 @@ protected void handleArgs() {
 					try {
 						Field f = c.getField(o.fieldName);
 						if ( argValue==null ) {
-							if ( o.fieldName.startsWith("-no-") ) f.setBoolean(this, false);
+							if ( arg.startsWith("-no-") ) f.setBoolean(this, false);
 							else f.setBoolean(this, true);
 						}
 						else f.set(this, argValue);
@@ -208,6 +210,9 @@ protected void handleArgs() {
 					}
 				}
 			}
+			if ( !found ) {
+				errMgr.toolError(ErrorType.INVALID_CMDLINE_ARG, arg);
+			}
 		}
 		if ( outputDirectory!=null ) {
 			if (outputDirectory.endsWith("/") ||

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

@@ -46,9 +46,13 @@ public void process() {
 		}
 		else {
 			gen.writeRecognizer(gen.generateParser());
-			if ( g.tool.gen_listener) {
+			if ( g.tool.gen_listener ) {
 				gen.writeListener(gen.generateListener());
-				gen.writeBlankListener(gen.generateBlankListener());
+				gen.writeBaseListener(gen.generateBaseListener());
+			}
+			if ( g.tool.gen_visitor ) {
+				gen.writeVisitor(gen.generateVisitor());
+				gen.writeBaseVisitor(gen.generateBaseVisitor());
 			}
 			gen.writeHeaderFile();
 		}