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/********************* */
/*! \file bound_var_manager.h
** \verbatim
** Top contributors (to current version):
** Andrew Reynolds
** This file is part of the CVC4 project.
** Copyright (c) 2009-2021 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 Bound variable manager utility
**/
#include "cvc4_private.h"
#ifndef CVC4__EXPR__BOUND_VAR_MANAGER_H
#define CVC4__EXPR__BOUND_VAR_MANAGER_H
#include <string>
#include <unordered_set>
#include "expr/node.h"
namespace CVC4 {
/**
* Bound variable manager.
*
* This class is responsible for constructing BOUND_VARIABLE that are
* canonical based on cache keys (Node). It does this using expression
* attributes on these nodes.
*/
class BoundVarManager
{
public:
BoundVarManager();
~BoundVarManager();
/**
* Enable or disable keeping cache values. If we keep cache values, then
* the bound variables returned by the methods below are deterministic in the
* lifetime of the NodeManager we are using.
*/
void enableKeepCacheValues(bool isEnabled = true);
/**
* Make a bound variable of type tn and name tn, cached based on (T, n),
* where T is an attribute class of the form:
* expr::Attribute<id, Node>
* This variable is unique for (T, n) during the lifetime of n. If
* this bound variable manager is configured to keep cache values, then
* n is added to the d_cacheVals set and survives in the lifetime of the
* current node manager.
*
* Returns the bound variable.
*/
template <class T>
Node mkBoundVar(Node n, TypeNode tn)
{
T attr;
if (n.hasAttribute(attr))
{
Assert(n.getAttribute(attr).getType() == tn);
return n.getAttribute(attr);
}
Node v = NodeManager::currentNM()->mkBoundVar(tn);
n.setAttribute(attr, v);
// if we are keeping cache values, insert it to the set
if (d_keepCacheVals)
{
d_cacheVals.insert(n);
}
return v;
}
/** Same as above, with a name for the bound variable. */
template <class T>
Node mkBoundVar(Node n, const std::string& name, TypeNode tn)
{
Node v = mkBoundVar<T>(n, tn);
setNameAttr(n, name);
return v;
}
//---------------------------------- utilities for computing Node hash
/** get cache value from two nodes, returns SEXPR */
static Node getCacheValue(TNode cv1, TNode cv2);
/** get cache value from two nodes and a size_t, returns SEXPR */
static Node getCacheValue(TNode cv1, TNode cv2, size_t i);
/** get cache value, returns a constant rational node */
static Node getCacheValue(size_t i);
/** get cache value, return SEXPR of cv and constant rational node */
static Node getCacheValue(TNode cv, size_t i);
//---------------------------------- end utilities for computing Node hash
private:
/** Set name of bound variable to name */
static void setNameAttr(Node v, const std::string& name);
/** Whether we keep cache values */
bool d_keepCacheVals;
/** The set of cache values we have used */
std::unordered_set<Node, NodeHashFunction> d_cacheVals;
};
} // namespace CVC4
#endif /* CVC4__EXPR__BOUND_VAR_MANAGER_H */
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