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// variable reference class -*- c++ -*-
#ifndef VARIABLE_H_
# define VARIABLE_H_
# ifdef __GNUC__
# pragma interface
# endif // __GNUC__
# include "Expression.h"
/** @file Variable.h
* Variable reference
*/
/* Copyright 1998-2001 Marko Mkel (msmakela@tcs.hut.fi).
This file is part of MARIA, a reachability analyzer and model checker
for high-level Petri nets.
MARIA is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
MARIA is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
The GNU General Public License is often shipped with GNU software, and
is generally kept in a file called COPYING or LICENSE. If you do not
have a copy of the license, write to the Free Software Foundation,
59 Temple Place, Suite 330, Boston, MA 02111 USA. */
/** Variable reference */
class Variable : public Expression
{
public:
/** Constructor
* @param variable Identifies the variable
* @param pred (for quantified variables)
* flag: use a predecessor value of the quantifier
*/
Variable (const class VariableDefinition& variable,
bool pred = false);
private:
/** Copy constructor */
Variable (const class Variable& old);
/** Assignment operator */
class Variable& operator= (const class Variable& old);
protected:
/** Destructor */
~Variable ();
public:
/** Determine the type of the expression */
enum Expression::Kind getKind () const { return eVariable; }
/** Determine whether this is a basic expression */
bool isBasic () const { return true; }
/** Determine whether this is a temporal logic expression */
bool isTemporal () const { return false; }
/** Determine the variable */
const class VariableDefinition& getVariable () const { return *myVariable; }
/** Set the type of the expression and the variable */
void setType (const class Type& type);
/** Equality comparison operator */
bool operator== (const class Variable& other) const {
return myVariable == other.myVariable && myPred == other.myPred;
}
/** Ordering comparison operator */
bool operator< (const class Variable& other) const {
if (myVariable < other.myVariable) return true;
if (other.myVariable < myVariable) return false;
return myPred < other.myPred;
}
/** Evaluate the expression
* @param valuation Variable substitutions
* @return Value of the expression, or NULL in case of error
*/
class Value* do_eval (const class Valuation& valuation) const;
/** Partially evaluate the expression using a valuation
* @param valuation Variable substitutions
* @param transition Transition for registering quantified variables
* @param declare flag: declare new variables if required
* @return grounded expression, or NULL in case of error
*/
class Expression* ground (const class Valuation& valuation,
class Transition* transition,
bool declare);
/** Substitute the variable with an expression, if possible
* @param substitution Variable substitutions
* @return substituted expression
*/
class Expression* substitute (class Substitution& substitution);
/** Determine whether the expression depends on a set of variables
* @param vars the set of variables
* @param complement flag: treat the set as its complement
*/
bool depends (const class VariableSet& vars,
bool complement) const;
/** Perform an operation on all subexpressions of the expression
* @param operation operation to be performed (return false on failure)
* @param data parameters to be passed to the operation
* @return true if all operations succeeded
*/
bool forExpressions (bool (*operation)
(const class Expression&,void*),
void* data) const;
/** Determine whether the expression is compatible with the specified value,
* neglecting subexpressions that cannot be evaluated
* @param value value the expression will be compared to
* @param valuation variable substitutions
* @return true if the expression is compatible with the value
*/
bool isCompatible (const class Value& value,
const class Valuation& valuation) const;
/** Unify variables from this expression
* @param value the value the expression should evaluate to
* @param valuation variable substitutions
* @param vars the variables to unify
*/
void getLvalues (const class Value& value,
class Valuation& valuation,
const class VariableSet& vars) const;
/** Determine which variables could be unified from this expression
* @param rvalues variables unified so far
* @param lvalues (output) variables that could be unified
* @return variables that could be unified
*/
void getLvalues (const class VariableSet& rvalues,
class VariableSet*& lvalues) const;
# ifdef EXPR_COMPILE
/** Generate lvalue gathering code
* @param cexpr the compilation
* @param indent level of indentation
* @param vars the variables
* @param lvalue C expression referring to the value
*/
void compileLvalue (class CExpression& cexpr,
unsigned indent,
const class VariableSet& vars,
const char* lvalue) const;
/** Generate compatibility check code
* @param cexpr the compilation
* @param indent level of indentation
* @param vars the variables that have been unified
* @param value C expression referring to the desired value
*/
void compileCompatible (class CExpression& cexpr,
unsigned indent,
const class VariableSet& vars,
const char* value) const;
/** Generate C code for evaluating the expression
* @param cexpr the compilation
* @param indent indentation level
* @param lvalue C expression referring to the lvalue
* @param vars the variables that have been assigned a value
*/
void compile (class CExpression& cexpr,
unsigned indent,
const char* lvalue,
const class VariableSet* vars) const;
# endif // EXPR_COMPILE
/** Display the expression
* @param printer the printer object
*/
void display (const class Printer& printer) const;
private:
/** Name of the variable */
const class VariableDefinition* myVariable;
/** Flag: use a predecessor value of the quantifier */
bool myPred;
};
#endif // VARIABLE_H_
|
