Java Code Examples for kodkod.ast.BinaryFormula#left()

@Override
public Formula visit(BinaryFormula bf) {
    Formula ans;
    switch (bf.op()) {
        case AND :
        case OR :
            Formula left = bf.left().accept(this);
            Formula right = bf.right().accept(this);
            Pair p = new Pair(left, right);
            if (p.hasNoQuant() && left == bf.left() && right == bf.right())
                ans = bf;
            else
                ans = p.compose(bf.op());
            break;
        case IMPLIES :
            ans = bf.left().not().or(bf.right()).accept(this);
            break;
        case IFF :
            ans = bf.left().and(bf.right()).or(bf.left().not().and(bf.right().not())).accept(this);
            break;
        default :
            throw new IllegalStateException("Unknown BinaryFormula operator: " + bf.op());
    }
    return saveMapping(ans, bf);
}
 

/**
 * If not cached, visits the formula's children with appropriate settings
 * for the negated flag and the skolemDepth parameter.
 * @see kodkod.ast.visitor.AbstractReplacer#visit(kodkod.ast.BinaryFormula)
 */
public final Formula visit(BinaryFormula bf) {
	Formula ret = lookup(bf);
	if (ret!=null) return ret;			
	final FormulaOperator op = bf.op();
	final int oldDepth = skolemDepth;
	if (op==IFF || (negated && op==AND) || (!negated && (op==OR || op==IMPLIES))) { // cannot skolemize in these cases
		skolemDepth = -1;
	}
	final Formula left, right;
	if (negated && op==IMPLIES) { // !(a => b) = !(!a || b) = a && !b
		negated = !negated;
		left = bf.left().accept(this);
		negated = !negated;
		right = bf.right().accept(this);
	} else {
		left = bf.left().accept(this);
		right = bf.right().accept(this);
	}
	skolemDepth = oldDepth;
	ret = (left==bf.left()&&right==bf.right()) ? bf : left.compose(op, right);
	return source(cache(bf,ret),bf);
}
 

/**
 * Calls lookup(binFormula) and returns the cached value, if any. If a
 * replacement has not been cached, visits the formula's children. If nothing
 * changes, the argument is cached and returned, otherwise a replacement formula
 * is cached and returned.
 *
 * @return { b: BinaryFormula | b.left = binExpr.left.accept(delegate) &&
 *         b.right = binExpr.right.accept(delegate) && b.op = binExpr.op }
 */
@Override
public Formula visit(BinaryFormula binFormula) {
    Formula ret = lookup(binFormula);
    if (ret != null)
        return ret;

    final Formula left = binFormula.left().accept(delegate);
    final Formula right = binFormula.right().accept(delegate);
    ret = (left == binFormula.left() && right == binFormula.right()) ? binFormula : left.compose(binFormula.op(), right);
    return cache(binFormula, ret);
}
 

/**
 * If this formula should be visited, then we visit its children only if they
 * could have contributed to the unsatisfiability of the top-level formula. For
 * example, let binFormula = "p && q", binFormula simplified to FALSE, p
 * simplified to FALSE and q was not simplified, then only p should be visited
 * since p caused binFormula's reduction to FALSE.
 */
@Override
public void visit(BinaryFormula binFormula) {
    if (visited(binFormula))
        return;
    relevant.add(binFormula);

    final Formula l = binFormula.left(), r = binFormula.right();
    final Boolean lval = constNodes.get(l), rval = constNodes.get(r);
    final boolean lvisit, rvisit;

    switch (binFormula.op()) {
        case AND :
            lvisit = (lval == Boolean.FALSE || (lval == null && rval != Boolean.FALSE));
            rvisit = (rval != Boolean.TRUE && lval != Boolean.FALSE);
            break;
        case OR :
            lvisit = (lval == Boolean.TRUE || (lval == null && rval != Boolean.TRUE));
            rvisit = (rval != Boolean.FALSE && lval != Boolean.TRUE);
            break;
        case IMPLIES : // !l || r
            lvisit = (lval == Boolean.FALSE || (lval == null && rval != Boolean.TRUE));
            rvisit = (rval != Boolean.FALSE && lval != Boolean.FALSE);
            break;
        case IFF : // (!l || r) && (l || !r)
            lvisit = rvisit = true;
            break;
        default :
            throw new IllegalArgumentException("Unknown operator: " + binFormula.op());
    }

    if (lvisit) {
        l.accept(this);
    }
    if (rvisit) {
        r.accept(this);
    }
}
 

/**
 * If not cached, visits the formula's children with appropriate settings for
 * the negated flag and the skolemDepth parameter.
 *
 * @see kodkod.ast.visitor.AbstractReplacer#visit(kodkod.ast.BinaryFormula)
 */
@Override
public final Formula visit(BinaryFormula bf) {
    Formula ret = lookup(bf);
    if (ret != null)
        return ret;
    final FormulaOperator op = bf.op();
    final int oldDepth = skolemDepth;
    if (op == IFF || (negated && op == AND) || (!negated && (op == OR || op == IMPLIES))) { // cannot
                                                                                           // skolemize
                                                                                           // in
                                                                                           // these
                                                                                           // cases
        skolemDepth = -1;
    }
    final Formula left, right;
    if (negated && op == IMPLIES) { // !(a => b) = !(!a || b) = a && !b
        negated = !negated;
        left = bf.left().accept(this);
        negated = !negated;
        right = bf.right().accept(this);
    } else {
        left = bf.left().accept(this);
        right = bf.right().accept(this);
    }
    skolemDepth = oldDepth;
    ret = (left == bf.left() && right == bf.right()) ? bf : left.compose(op, right);
    return source(cache(bf, ret), bf);
}
 

/** 
 * Calls lookup(binFormula) and returns the cached value, if any.  
 * If a replacement has not been cached, visits the formula's 
 * children.  If nothing changes, the argument is cached and
 * returned, otherwise a replacement formula is cached and returned.
 * @return { b: BinaryFormula | b.left = binExpr.left.accept(this) &&
 *                              b.right = binExpr.right.accept(this) && b.op = binExpr.op }
 */
public Formula visit(BinaryFormula binFormula) {
	Formula ret = lookup(binFormula);
	if (ret!=null) return ret;
	
	final Formula left  = binFormula.left().accept(this);
	final Formula right = binFormula.right().accept(this);
	ret = (left==binFormula.left() && right==binFormula.right()) ? 
		  binFormula : left.compose(binFormula.op(), right);     
	return cache(binFormula,ret);
}
 

/**
 * If this formula should be visited, then we visit its children only
 * if they could have contributed to the unsatisfiability of the top-level
 * formula.  For example, let binFormula = "p && q", binFormula simplified
 * to FALSE, p simplified to FALSE and q was not simplified, then only p 
 * should be visited since p caused binFormula's reduction to FALSE.
 */
public void visit(BinaryFormula binFormula) {
	if (visited(binFormula)) return;
	relevant.add(binFormula);
	
	final Formula l = binFormula.left(), r = binFormula.right();
	final Boolean lval = constNodes.get(l), rval = constNodes.get(r);
	final boolean lvisit, rvisit;
	
	switch(binFormula.op()) {
	case AND : 
		lvisit = (lval==Boolean.FALSE || (lval==null && rval!=Boolean.FALSE));
		rvisit = (rval!=Boolean.TRUE && lval!=Boolean.FALSE);
		break;
	case OR :
		lvisit = (lval==Boolean.TRUE || (lval==null && rval!=Boolean.TRUE));
		rvisit = (rval!=Boolean.FALSE && lval!=Boolean.TRUE);
		break;
	case IMPLIES: // !l || r
		lvisit = (lval==Boolean.FALSE || (lval==null && rval!=Boolean.TRUE));
		rvisit = (rval!=Boolean.FALSE && lval!=Boolean.FALSE);
		break;
	case IFF: // (!l || r) && (l || !r) 
		lvisit = rvisit = true;
		break;
	default :
		throw new IllegalArgumentException("Unknown operator: " + binFormula.op());
	}	
	
	if (lvisit) { l.accept(this); }
	if (rvisit) { r.accept(this); }
}
 

/**
 * Returns an unmodifiable set consisting of the children of the given formula, if the formula is a binary or an nary conjunction.  Otherwise
 * returns a singleton set containing the formula itself.
 * @return  an unmodifiable set consisting of children of the given formula, if the formula is a binary or an nary conjunction.  Otherwise
 * returns a singleton set containing the formula itself.
 */
public static Set<Formula> conjuncts(Formula formula) { 
	if (formula instanceof BinaryFormula) { 
		final BinaryFormula bin = (BinaryFormula) formula;
		if (bin.op()==FormulaOperator.AND) {
			final Formula left = bin.left(), right = bin.right();
			if (left==right) return Collections.singleton(left);
			else return new AbstractSet<Formula>() {
				@Override
				public boolean contains(Object o) { return left==o || right==o; }
				@Override
				public Iterator<Formula> iterator() { return Containers.iterate(left, right); }
				@Override
				public int size() { return 2;	}
				
			};
		}
	} else if (formula instanceof NaryFormula) { 
		final NaryFormula nf = (NaryFormula) formula;
		if (nf.op()==FormulaOperator.AND) { 
			final LinkedHashSet<Formula> children = new LinkedHashSet<Formula>(1+(nf.size()*4)/3);
			for(Formula child : nf) { children.add(child); }
			return Collections.unmodifiableSet(children);
		}
	} 
	
	return Collections.singleton(formula);
	
}
 

public Formula visit(BinaryFormula formula) { 
	Formula ret = lookup(formula);
	if (ret!=null) return ret;
	final FormulaOperator op = formula.op();
	if (op==FormulaOperator.AND) {
		final Set<Formula> conjuncts = kodkod.util.nodes.Nodes.roots(formula);
		if (conjuncts.size()>2) { 
			return cache(formula, Formula.and(conjuncts).accept(this));
		}
	}
	
	final Formula left = formula.left().accept(this);
	final Formula right = formula.right().accept(this);
	
	ret = simplify(op, left, right);
	
	if (ret==null) {
	
		final int hash = hash(op, left, right);
		for(Iterator<PartialCannonicalizer.Holder<Formula>> itr = formulas.get(hash); itr.hasNext(); ) {
			final Formula next = itr.next().obj;
			if (next instanceof BinaryFormula) { 
				final BinaryFormula hit = (BinaryFormula) next;
				if (hit.op()==op && hit.left()==left && hit.right()==right) { 
					return cache(formula, hit);
				}
			}
		}

		ret = left==formula.left()&&right==formula.right() ? formula : left.compose(op, right);
		formulas.add(new PartialCannonicalizer.Holder<Formula>(ret, hash));
	}
	
	return cache(formula,ret);
}
 

public Formula visit(BinaryFormula expr) { 
	Formula ret = lookup(expr);
	if (ret!=null) return ret;
	final FormulaOperator op = expr.op();
	final Formula left = expr.left().accept(this);
	final Formula right = expr.right().accept(this);
	
	ret = simplify(op, left, right);
	
	if (ret==null) {
		ret = left==expr.left()&&right==expr.right() ? expr : left.compose(op, right);
	}
	
	return cache(expr,ret);
}
 

/**
 * Returns an unmodifiable set consisting of the children of the given formula,
 * if the formula is a binary or an nary conjunction. Otherwise returns a
 * singleton set containing the formula itself.
 *
 * @return an unmodifiable set consisting of children of the given formula, if
 *         the formula is a binary or an nary conjunction. Otherwise returns a
 *         singleton set containing the formula itself.
 */
public static Set<Formula> conjuncts(Formula formula) {
    if (formula instanceof BinaryFormula) {
        final BinaryFormula bin = (BinaryFormula) formula;
        if (bin.op() == FormulaOperator.AND) {
            final Formula left = bin.left(), right = bin.right();
            if (left == right)
                return Collections.singleton(left);
            else
                return new AbstractSet<Formula>() {

                    @Override
                    public boolean contains(Object o) {
                        return left == o || right == o;
                    }

                    @Override
                    public Iterator<Formula> iterator() {
                        return Containers.iterate(left, right);
                    }

                    @Override
                    public int size() {
                        return 2;
                    }

                };
        }
    } else if (formula instanceof NaryFormula) {
        final NaryFormula nf = (NaryFormula) formula;
        if (nf.op() == FormulaOperator.AND) {
            final LinkedHashSet<Formula> children = new LinkedHashSet<Formula>(1 + (nf.size() * 4) / 3);
            for (Formula child : nf) {
                children.add(child);
            }
            return Collections.unmodifiableSet(children);
        }
    }

    return Collections.singleton(formula);

}