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/********************* */
/*! \file proof_checker.cpp
** \verbatim
** Top contributors (to current version):
** Haniel Barbosa, Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2019 by the authors listed in the file AUTHORS
** in the top-level source directory) and their institutional affiliations.
** All rights reserved. See the file COPYING in the top-level source
** directory for licensing information.\endverbatim
**
** \brief Implementation of equality proof checker
**/
#include "theory/uf/proof_checker.h"
using namespace CVC4::kind;
namespace CVC4 {
namespace theory {
namespace uf {
void UfProofRuleChecker::registerTo(ProofChecker* pc)
{
// add checkers
pc->registerChecker(PfRule::REFL, this);
pc->registerChecker(PfRule::SYMM, this);
pc->registerChecker(PfRule::TRANS, this);
pc->registerChecker(PfRule::CONG, this);
pc->registerChecker(PfRule::TRUE_INTRO, this);
pc->registerChecker(PfRule::TRUE_ELIM, this);
pc->registerChecker(PfRule::FALSE_INTRO, this);
pc->registerChecker(PfRule::FALSE_ELIM, this);
}
Node UfProofRuleChecker::checkInternal(PfRule id,
const std::vector<Node>& children,
const std::vector<Node>& args)
{
// compute what was proven
if (id == PfRule::REFL)
{
Assert(children.empty());
Assert(args.size() == 1);
return args[0].eqNode(args[0]);
}
else if (id == PfRule::SYMM)
{
Assert(children.size() == 1);
Assert(args.empty());
bool polarity = children[0].getKind() != NOT;
Node eqp = polarity ? children[0] : children[0][0];
if (eqp.getKind() != EQUAL)
{
// not a (dis)equality
return Node::null();
}
Node conc = eqp[1].eqNode(eqp[0]);
return polarity ? conc : conc.notNode();
}
else if (id == PfRule::TRANS)
{
Assert(children.size() > 0);
Assert(args.empty());
Node first;
Node curr;
for (size_t i = 0, nchild = children.size(); i < nchild; i++)
{
Node eqp = children[i];
if (eqp.getKind() != EQUAL)
{
return Node::null();
}
if (first.isNull())
{
first = eqp[0];
}
else if (eqp[0] != curr)
{
return Node::null();
}
curr = eqp[1];
}
return first.eqNode(curr);
}
else if (id == PfRule::CONG)
{
Assert(children.size() > 0);
Assert(args.size() == 1);
// We do congruence over builtin kinds using operatorToKind
std::vector<Node> lchildren;
std::vector<Node> rchildren;
// get the expected kind for args[0]
Kind k = NodeManager::getKindForFunction(args[0]);
if (k == kind::UNDEFINED_KIND)
{
k = NodeManager::operatorToKind(args[0]);
}
if (k == kind::UNDEFINED_KIND)
{
return Node::null();
}
Trace("uf-pfcheck") << "congruence for " << args[0] << " uses kind " << k
<< ", metakind=" << kind::metaKindOf(k) << std::endl;
if (kind::metaKindOf(k) == kind::metakind::PARAMETERIZED)
{
// parameterized kinds require the operator
lchildren.push_back(args[0]);
rchildren.push_back(args[0]);
}
for (size_t i = 0, nchild = children.size(); i < nchild; i++)
{
Node eqp = children[i];
if (eqp.getKind() != EQUAL)
{
return Node::null();
}
lchildren.push_back(eqp[0]);
rchildren.push_back(eqp[1]);
}
NodeManager* nm = NodeManager::currentNM();
Node l = nm->mkNode(k, lchildren);
Node r = nm->mkNode(k, rchildren);
return l.eqNode(r);
}
else if (id == PfRule::TRUE_INTRO)
{
Assert(children.size() == 1);
Assert(args.empty());
Node trueNode = NodeManager::currentNM()->mkConst(true);
return children[0].eqNode(trueNode);
}
else if (id == PfRule::TRUE_ELIM)
{
Assert(children.size() == 1);
Assert(args.empty());
if (children[0].getKind() != EQUAL || !children[0][1].isConst()
|| !children[0][1].getConst<bool>())
{
return Node::null();
}
return children[0][0];
}
else if (id == PfRule::FALSE_INTRO)
{
Assert(children.size() == 1);
Assert(args.empty());
if (children[0].getKind() != kind::NOT)
{
return Node::null();
}
Node falseNode = NodeManager::currentNM()->mkConst(false);
return children[0][0].eqNode(falseNode);
}
else if (id == PfRule::FALSE_ELIM)
{
Assert(children.size() == 1);
Assert(args.empty());
if (children[0].getKind() != EQUAL || !children[0][1].isConst()
|| children[0][1].getConst<bool>())
{
return Node::null();
}
return children[0][0].notNode();
}
// no rule
return Node::null();
}
} // namespace uf
} // namespace theory
} // namespace CVC4
|
