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/********************* */
/*! \file theory_bool.cpp
** \verbatim
** Original author: mdeters
** Major contributors: dejan
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010, 2011 The Analysis of Computer Systems Group (ACSys)
** Courant Institute of Mathematical Sciences
** New York University
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief The theory of booleans.
**
** The theory of booleans.
**/
#include "theory/theory.h"
#include "theory/booleans/theory_bool.h"
#include "theory/booleans/circuit_propagator.h"
#include "theory/valuation.h"
#include "util/boolean_simplification.h"
#include <vector>
#include <stack>
#include "util/hash.h"
using namespace std;
namespace CVC4 {
namespace theory {
namespace booleans {
Node TheoryBool::getValue(TNode n) {
NodeManager* nodeManager = NodeManager::currentNM();
switch(n.getKind()) {
case kind::VARIABLE:
// case for Boolean vars is implemented in TheoryEngine (since it
// appeals to the PropEngine to get the value)
Unreachable();
case kind::EQUAL: // 2 args
// should be handled by IFF
Unreachable();
case kind::NOT: { // 1 arg
Node v = d_valuation.getValue(n[0]);
return v.isNull() ? Node::null() : nodeManager->mkConst(! v.getConst<bool>());
}
case kind::AND: { // 2+ args
bool foundNull = false;
for(TNode::iterator i = n.begin(),
iend = n.end();
i != iend;
++i) {
Node v = d_valuation.getValue(*i);
if(v.isNull()) {
foundNull = true;
} else if(! v.getConst<bool>()) {
return nodeManager->mkConst(false);
}
}
return foundNull ? Node::null() : nodeManager->mkConst(true);
}
case kind::IFF: { // 2 args
Node v0 = d_valuation.getValue(n[0]);
Node v1 = d_valuation.getValue(n[1]);
if(v0.isNull() || v1.isNull()) {
return Node::null();
}
return nodeManager->mkConst( v0.getConst<bool>() == v1.getConst<bool>() );
}
case kind::IMPLIES: { // 2 args
Node v0 = d_valuation.getValue(n[0]);
Node v1 = d_valuation.getValue(n[1]);
if(v0.isNull() && v1.isNull()) {
return Node::null();
}
bool value = false;
if(! v0.isNull()) {
value = value || (! v0.getConst<bool>());
}
if(! v1.isNull()) {
value = value || v1.getConst<bool>();
}
return nodeManager->mkConst(value);
}
case kind::OR: { // 2+ args
bool foundNull = false;
for(TNode::iterator i = n.begin(),
iend = n.end();
i != iend;
++i) {
Node v = d_valuation.getValue(*i);
if(v.isNull()) {
foundNull = true;
} else if(v.getConst<bool>()) {
return nodeManager->mkConst(true);
}
}
return foundNull ? Node::null() : nodeManager->mkConst(false);
}
case kind::XOR: { // 2 args
Node v0 = d_valuation.getValue(n[0]);
Node v1 = d_valuation.getValue(n[1]);
if(v0.isNull() || v1.isNull()) {
return Node::null();
}
return nodeManager->mkConst( v0.getConst<bool>() != v1.getConst<bool>() );
}
case kind::ITE: { // 3 args
// all ITEs should be gone except (bool,bool,bool) ones
Assert( n[1].getType() == nodeManager->booleanType() &&
n[2].getType() == nodeManager->booleanType() );
Node v0 = d_valuation.getValue(n[0]);
Node v1 = d_valuation.getValue(n[1]);
Node v2 = d_valuation.getValue(n[2]);
if(v0.isNull()) {
return v1 == v2 ? v1 : Node::null();
}
return nodeManager->mkConst( v0.getConst<bool>() ? v1.getConst<bool>() : v2.getConst<bool>() );
}
default:
Unhandled(n.getKind());
}
}
Theory::PPAssertStatus TheoryBool::ppAsert(TNode in, SubstitutionMap& outSubstitutions) {
if (in.getKind() == kind::CONST_BOOLEAN && !in.getConst<bool>()) {
// If we get a false literal, we're in conflict
return PP_ASSERT_STATUS_CONFLICT;
}
// Add the substitution from the variable to it's value
if (in.getKind() == kind::NOT) {
if (in[0].getKind() == kind::VARIABLE) {
outSubstitutions.addSubstitution(in[0], NodeManager::currentNM()->mkConst<bool>(false));
} else {
return PP_ASSERT_STATUS_UNSOLVED;
}
} else {
if (in.getKind() == kind::VARIABLE) {
outSubstitutions.addSubstitution(in, NodeManager::currentNM()->mkConst<bool>(true));
} else {
return PP_ASSERT_STATUS_UNSOLVED;
}
}
return PP_ASSERT_STATUS_SOLVED;
}
}/* CVC4::theory::booleans namespace */
}/* CVC4::theory namespace */
}/* CVC4 namespace */
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