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/********************* */
/** theory_engine.cpp
** Original author: mdeters
** Major contributors: none
** Minor contributors (to current version): none
** This file is part of the CVC4 prototype.
** Copyright (c) 2009, 2010 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.
**
** The theory engine.
**/
#include "theory/theory_engine.h"
#include "expr/node.h"
#include "expr/attribute.h"
#include <list>
using namespace std;
namespace CVC4 {
namespace theory {
struct PreRegisteredTag {};
typedef expr::Attribute<PreRegisteredTag, bool> PreRegistered;
}/* CVC4::theory namespace */
Node TheoryEngine::preprocess(TNode t) {
Node top = rewrite(t);
Debug("rewrite") << "rewrote: " << t << "\nto : " << top << "\n";
return top;
list<TNode> toReg;
toReg.push_back(top);
/* Essentially this is doing a breadth-first numbering of
* non-registered subterms with children. Any non-registered
* leaves are immediately registered. */
for(list<TNode>::iterator workp = toReg.begin();
workp != toReg.end();
++workp) {
TNode n = *workp;
for(TNode::iterator i = n.begin(); i != n.end(); ++i) {
TNode c = *i;
if(!c.getAttribute(theory::PreRegistered())) {// c not yet registered
if(c.getNumChildren() == 0) {
c.setAttribute(theory::PreRegistered(), true);
theoryOf(c)->preRegisterTerm(c);
} else {
toReg.push_back(c);
}
}
}
}
/* Now register the list of terms in reverse order. Between this
* and the above registration of leaves, this should ensure that
* all subterms in the entire tree were registered in
* reverse-topological order. */
for(std::list<TNode>::reverse_iterator i = toReg.rbegin();
i != toReg.rend();
++i) {
TNode n = *i;
/* Note that a shared TNode in the DAG rooted at "fact" could
* appear twice on the list, so we have to avoid hitting it
* twice. */
// FIXME when ExprSets are online, use one of those to avoid
// duplicates in the above?
if(!n.getAttribute(theory::PreRegistered())) {
n.setAttribute(theory::PreRegistered(), true);
theoryOf(n)->preRegisterTerm(n);
}
}
return top;
}
Node TheoryEngine::rewrite(TNode in) {
if(inRewriteCache(in)) {
return getRewriteCache(in);
}
if(in.getMetaKind() == kind::metakind::VARIABLE) {
return in;
}
/*
theory::Theory* thy = theoryOf(in);
if(thy == NULL) {
Node out = rewriteBuiltins(in);
setRewriteCache(in, out);
return in;
} else {
Node out = thy->rewrite(in);
setRewriteCache(in, out);
return out;
}
*/
// these special cases should go away when theory rewriting comes online
if(in.getKind() == kind::EQUAL) {
Assert(in.getNumChildren() == 2);
if(in[0] == in[1]) {
Node out = NodeManager::currentNM()->mkConst(true);
//setRewriteCache(in, out);
return out;
}
} else if(in.getKind() == kind::DISTINCT) {
vector<Node> diseqs;
for(TNode::iterator i = in.begin(); i != in.end(); ++i) {
TNode::iterator j = i;
while(++j != in.end()) {
Node eq = NodeManager::currentNM()->mkNode(CVC4::kind::EQUAL, *i, *j);
Node neq = NodeManager::currentNM()->mkNode(CVC4::kind::NOT, eq);
diseqs.push_back(neq);
}
}
Node out =
diseqs.size() == 1
? diseqs[0]
: NodeManager::currentNM()->mkNode(CVC4::kind::AND, diseqs);
//setRewriteCache(in, out);
return out;
} else {
Node out = rewriteChildren(in);
//setRewriteCache(in, out);
return out;
}
//setRewriteCache(in, in);
return in;
}
}/* CVC4 namespace */
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