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/********************* */
/*! \file idl_assertion.h
** \verbatim
** Original author: Dejan Jovanovic
** Major contributors: Morgan Deters
** Minor contributors (to current version): none
** This file is part of the CVC4 project.
** Copyright (c) 2009-2014 New York University and The University of Iowa
** See the file COPYING in the top-level source directory for licensing
** information.\endverbatim
**
** \brief [[ Add one-line brief description here ]]
**
** [[ Add lengthier description here ]]
** \todo document this file
**/
#pragma once
#include "theory/idl/idl_model.h"
namespace CVC4 {
namespace theory {
namespace idl {
/**
* An internal representation of the IDL assertions. Each IDL assertions is
* of the form (x - y op c) where op is one of (<=, =, !=). IDL assertion
* can be constructed from an expression.
*/
class IDLAssertion {
/** The positive variable */
TNode d_x;
/** The negative variable */
TNode d_y;
/** The relation */
Kind d_op;
/** The RHS constant */
Integer d_c;
/** Original assertion we got this one from */
TNode d_original;
/** Parses the given node into an assertion, and return true if OK. */
bool parse(TNode node, int c = 1, bool negated = false);
public:
/** Null assertion */
IDLAssertion();
/** Create the assertion from given node */
IDLAssertion(TNode node);
/** Copy constructor */
IDLAssertion(const IDLAssertion& other);
TNode getX() const { return d_x; }
TNode getY() const { return d_y; }
Kind getOp() const { return d_op;}
Integer getC() const { return d_c; }
/**
* Propagate the constraint using the model. For example, if the constraint
* is of the form x - y <= -1, and the value of x in the model is 0, then
*
* (x - y <= -1) and (x = 0) implies y >= x + 1 = 1
*
* If the value of y is less then 1, is is set to 1 and true is returned. If
* the value of y is 1 or more, than false is return.
*
* @return true if value of y was updated
*/
bool propagate(IDLModel& model) const;
/** Is this constraint proper */
bool ok() const {
return !d_x.isNull() || !d_y.isNull();
}
/** Output to the stream */
void toStream(std::ostream& out) const;
};
inline std::ostream& operator << (std::ostream& out, const IDLAssertion& assertion) {
assertion.toStream(out);
return out;
}
}
}
}
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