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//==============================================================================
//
// Copyright (c) 2002-
// Authors:
// * Dave Parker <david.parker@comlab.ox.ac.uk> (University of Oxford, formerly University of Birmingham)
//
//------------------------------------------------------------------------------
//
// This file is part of PRISM.
//
// PRISM 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 of the License, or
// (at your option) any later version.
//
// PRISM 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.
//
// You should have received a copy of the GNU General Public License
// along with PRISM; if not, write to the Free Software Foundation,
// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
//==============================================================================
package parser.ast;
import parser.*;
import parser.visitor.*;
import prism.PrismLangException;
import parser.type.*;
public class ExpressionVar extends Expression
{
// Variable name
private String name;
// The index of the variable in the model to which it belongs
private int index;
// Constructors
public ExpressionVar(String n, Type t)
{
setType(t);
name = n;
index = -1;
}
// Set method
public void setName(String n)
{
name = n;
}
public void setIndex(int i)
{
index = i;
}
// Get method
public String getName()
{
return name;
}
public int getIndex()
{
return index;
}
// Methods required for Expression:
/**
* Is this expression constant?
*/
public boolean isConstant()
{
return false;
}
/**
* Evaluate this expression, return result.
* Note: assumes that type checking has been done already.
*/
public Object evaluate(EvaluateContext ec) throws PrismLangException
{
Object res = ec.getVarValue(name, index);
if (res == null)
throw new PrismLangException("Could not evaluate variable", this);
return res;
}
@Override
public boolean returnsSingleValue()
{
return false;
}
// Methods required for ASTElement:
/**
* Visitor method.
*/
public Object accept(ASTVisitor v) throws PrismLangException
{
return v.visit(this);
}
/**
* Convert to string.
*/
public String toString()
{
return name;
}
/**
* Perform a deep copy.
*/
public Expression deepCopy()
{
ExpressionVar expr = new ExpressionVar(name, type);
expr.setIndex(index);
expr.setPosition(this);
return expr;
}
}
//------------------------------------------------------------------------------