forked from jasder/antlr
87 lines
3.3 KiB
Java
87 lines
3.3 KiB
Java
/*
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[The "BSD license"]
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Copyright (c) 2011 Terence Parr
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. The name of the author may not be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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import org.antlr.v4.runtime.ANTLRFileStream;
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import org.antlr.v4.runtime.CommonTokenStream;
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import org.antlr.v4.runtime.ParserRuleContext;
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import org.antlr.v4.runtime.Token;
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import org.antlr.v4.runtime.tree.ParseTreeWalker;
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public class TestA2 {
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/** An example listener that squirrels away a return value in a field
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* called v that we get added to the expression context objects
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* by adding a return value to rule e. This is a version of A.g4
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* that performs actions during the parse with user-defined actions.
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* AND, we pass in a listener that gets executed during the parse
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* and we use a listener on a tree walk that executes after the parse.
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* So, it affect, we compute the result of the expression 3 times.
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*/
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public static class Do extends A2BaseListener {
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A2Parser p;
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public Do(A2Parser p) { this.p = p; }
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@Override
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public void exitAdd(A2Parser.AddContext ctx) {
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ctx.v = ctx.e(0).v + ctx.e(1).v;
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System.out.println("Add: " + ctx.v);
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}
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@Override
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public void exitInt(A2Parser.IntContext ctx) {
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ctx.v = Integer.valueOf(ctx.INT().getSymbol().getText());
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System.out.println("Int: "+ctx.v);
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}
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@Override
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public void exitMult(A2Parser.MultContext ctx) {
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ctx.v = ctx.e(0).v * ctx.e(1).v;
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System.out.println("Mult: " + ctx.v);
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}
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@Override
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public void exitParens(A2Parser.ParensContext ctx) {
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ctx.v = ctx.e().v;
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System.out.println("Parens: "+ctx.v);
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}
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}
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public static void main(String[] args) throws Exception {
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A2Lexer lexer = new A2Lexer(new ANTLRFileStream(args[0]));
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CommonTokenStream tokens = new CommonTokenStream(lexer);
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A2Parser p = new A2Parser(tokens);
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p.setBuildParseTree(true);
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ParserRuleContext<Token> t = p.s();
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System.out.println("tree = "+t.toStringTree(p));
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ParseTreeWalker walker = new ParseTreeWalker();
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Do doer = new Do(p);
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walker.walk(doer, t);
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A2Parser.EContext ectx = (A2Parser.EContext)t.getChild(0);
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System.out.println("result from tree walk = "+ ectx.v);
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}
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}
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