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/********************* */
/*! \file rewriterules.h
** \verbatim
** Original author: bobot
** Major contributors: none
** 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 One utilitise for rewriterules definition
**
**/
#ifndef __CVC4__REWRITERULES_H
#define __CVC4__REWRITERULES_H
#include <vector>
#include <hash_set>
#include <hash_map>
#include "expr/expr.h"
#include "expr/node.h"
#include "theory/rewriterules/theory_rewriterules_params.h"
#include "theory/uf/theory_uf.h"
namespace CVC4 {
namespace theory {
namespace rewriterules {
namespace rewriter{
typedef Node TMPNode;
typedef std::vector<Node> Subst;
typedef std::vector<Expr> ESubst;
typedef std::vector<TMPNode> TSubst;
struct Step{
/** match the node and add in Vars the found variables */
virtual Node run(TMPNode node) = 0;
virtual bool add(TMPNode pattern, TMPNode body, Subst & pvars, Subst & vars) = 0;
};
struct FinalStep : Step {
Node body;
TSubst vars;
Node subst(Subst & subst){
return body.substitute(vars.begin(), vars.end(),
subst.begin(), subst.end());
}
};
typedef std::hash_map< Node, int, NodeHashFunction > PVars;
struct Pattern : FinalStep{
Node pattern;
PVars pattern_vars;
Node run(TMPNode node){
Subst vars = Subst(pattern_vars.size(),Node::null());
typedef std::vector<std::pair<TMPNode,TMPNode> > tstack;
tstack stack(1,std::make_pair(node,pattern)); // t * pat
while(!stack.empty()){
const std::pair<TMPNode,TMPNode> p = stack.back(); stack.pop_back();
const TMPNode & t = p.first;
const TMPNode & pat = p.second;
// pat is a variable
if( pat.getKind() == kind::INST_CONSTANT ||
pat.getKind() == kind::VARIABLE){
PVars::iterator i = pattern_vars.find(pat);
Assert(i != pattern_vars.end());
if(vars[i->second].isNull()) vars[i->second] = t;
if(vars[i->second] == t) continue;
return Node::null();
};
// t is not an UF application
if( t.getKind() != kind::APPLY_UF ){
if (t == pat) continue;
else return Node::null();
};
//different UF_application
if( t.getOperator() != pat.getOperator() ) return Node::null();
//put the children on the stack
for( size_t i=0; i < pat.getNumChildren(); i++ ){
stack.push_back(std::make_pair(t[i],pat[i]));
};
}
// Matching is done
return subst(vars);
}
bool add(TMPNode pattern, TMPNode body, Subst & pvars, Subst & vars){
return false;
}
};
struct Args : Step {
typedef std::vector<Pattern> Patterns;
Patterns d_matches;
Node run(TMPNode node){
Node n;
for (Patterns::iterator i = d_matches.begin();
i != d_matches.end() && n.isNull(); ++i){
Debug("rewriterules-rewrite") << "test?" << i->pattern << std::endl;
n = i->run(node);
}
return n;
}
bool add(TMPNode pattern, TMPNode body, Subst & pvars, Subst & vars){
Debug("rewriterules-rewrite") << "theoryrewrite::Args::add" << "("
<< d_matches.size() << ")"
<< pattern << "->" << body << std::endl;
d_matches.push_back(Pattern());
Pattern & p = d_matches.back();
p.body = body;
p.vars.reserve(vars.size());
for( size_t i=0; i < vars.size(); i++ ){
p.vars.push_back(vars[i]);
};
p.pattern = pattern;
for( size_t i=0; i < pvars.size(); i++ ){
p.pattern_vars[pvars[i]] = i;
};
return true;
};
void clear(){
d_matches.clear();
}
};
class RRPpRewrite : public uf::TheoryUF::PpRewrite {
Args d_pattern;
public:
Node ppRewrite(TNode node){
Debug("rewriterules-rewrite") << "rewrite?" << node << std::endl;
Node t = d_pattern.run(node);
Debug("rewriterules-rewrite") << "rewrite:" << node
<< (t.isNull()? " to": " to ")
<< t << std::endl;
if (t.isNull()) return node;
else return t;
}
bool addRewritePattern(TMPNode pattern, TMPNode body,
Subst & pvars, Subst & vars){
return d_pattern.add(pattern,body,pvars,vars);
}
};
}
}
}
}
#endif /* __CVC4__REWRITERULES_H */
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