/*******************************************************************************
* Copyright (c) 2009-2013 CWI
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* * Jurgen J. Vinju - Jurgen.Vinju@cwi.nl - CWI
* * Tijs van der Storm - Tijs.van.der.Storm@cwi.nl
* * Emilie Balland - (CWI)
* * Paul Klint - Paul.Klint@cwi.nl - CWI
* * Mark Hills - Mark.Hills@cwi.nl (CWI)
* * Arnold Lankamp - Arnold.Lankamp@cwi.nl
*******************************************************************************/
package org.rascalmpl.interpreter.matching;
import org.eclipse.imp.pdb.facts.IValue;
import org.eclipse.imp.pdb.facts.type.Type;
import org.rascalmpl.ast.Expression;
import org.rascalmpl.interpreter.IEvaluatorContext;
import org.rascalmpl.interpreter.result.Result;
import org.rascalmpl.interpreter.staticErrors.UnexpectedType;
public class MatchResult extends AbstractBooleanResult {
private boolean positive;
private IMatchingResult mp;
private Expression expression;
private boolean firstTime;
private Expression pattern;
public MatchResult(IEvaluatorContext ctx, Expression pattern, boolean positive, Expression expression) {
super(ctx);
this.positive = positive;
this.pattern = pattern;
this.mp = null;
this.expression = expression;
}
@Override
public void init() {
super.init();
// because the right hand side may introduce types that are needed
// in the left-hand side, we first need to evaluate the expression
// before we construct a pattern.
Result<IValue> result = expression.interpret(ctx.getEvaluator());
Type subjectType = result.getType();
mp = pattern.getMatcher(ctx);
mp.initMatch(result);
if(!mp.mayMatch(subjectType, ctx.getCurrentEnvt())) {
throw new UnexpectedType(mp.getType(ctx.getCurrentEnvt(), null), subjectType, ctx.getCurrentAST());
}
firstTime = true;
}
@Override
public boolean hasNext() {
if (firstTime) {
return true;
}
return mp.hasNext();
}
@Override
public boolean next() {
firstTime = false;
// TODO: should manage escape variable from negative matches!!!
if(hasNext()){
return positive ? mp.next() : !mp.next();
}
return !positive;
}
}