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Split Update into individual UpdateElement objects and make it iterable over.
accumulation-v4.7
Split Update into individual UpdateElement objects and make it iterable over.
accumulation-v4.7
Joachim Klein
8 years ago
committed by
Dave Parker
Dave Parker
5 changed files with 326 additions and 113 deletions
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195prism/src/parser/ast/Update.java
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220prism/src/parser/ast/UpdateElement.java
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11prism/src/parser/visitor/ASTTraverse.java
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12prism/src/parser/visitor/ASTTraverseModify.java
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1prism/src/parser/visitor/ASTVisitor.java
@ -0,0 +1,220 @@ |
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//============================================================================== |
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// |
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// Copyright (c) 2018 |
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// Authors: |
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// * Dave Parker <d.a.parker@cs.bham.ac.uk> (University of Birmingham) |
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// |
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//------------------------------------------------------------------------------ |
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// |
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// This file is part of PRISM. |
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// |
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// PRISM is free software; you can redistribute it and/or modify |
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// it under the terms of the GNU General Public License as published by |
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// the Free Software Foundation; either version 2 of the License, or |
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// (at your option) any later version. |
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// |
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// PRISM is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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// |
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// You should have received a copy of the GNU General Public License |
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// along with PRISM; if not, write to the Free Software Foundation, |
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// Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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// |
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//============================================================================== |
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|
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package parser.ast; |
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|
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import param.BigRational; |
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import parser.State; |
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import parser.Values; |
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import parser.VarList; |
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import parser.type.Type; |
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import parser.visitor.ASTVisitor; |
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import prism.PrismLangException; |
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|
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/** |
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* Class to store a single element of an Update, i.e. a single assignment (e.g. s'=1) |
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*/ |
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public class UpdateElement extends ASTElement |
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{ |
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/** The variable that is assigned to */ |
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private String var; |
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/** The expression for the assignment value */ |
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private Expression expr; |
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/** The type of the assignment (initially empty / unknown) */ |
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private Type type; |
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/** The identifier expression for the variable (for position information, etc) */ |
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private ExpressionIdent ident; |
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/** The variable index (initially unknown, i.e., -1) */ |
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private int index; |
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|
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/** Constructor */ |
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public UpdateElement(ExpressionIdent v, Expression e) |
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{ |
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var = v.getName(); |
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expr = e; |
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type = null; // Type currently unknown |
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ident = v; |
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index = -1; // Index currently unknown |
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} |
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|
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/** Shallow copy constructor */ |
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public UpdateElement(UpdateElement other) |
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{ |
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var = other.var; |
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expr = other.expr; |
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type = other.type; |
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ident = other.ident; |
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index = other.index; |
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} |
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|
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// Getters |
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|
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/** Get the name of the variable that is the assignment target */ |
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public String getVar() |
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{ |
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return var; |
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} |
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|
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/** Get the update expression */ |
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public Expression getExpression() |
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{ |
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return expr; |
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} |
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|
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/** Get the type of the update */ |
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public Type getType() |
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{ |
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return type; |
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} |
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|
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/** Get the ExpressionIdent corresponding to the variable name (for position information) */ |
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public ExpressionIdent getVarIdent() |
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{ |
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return ident; |
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} |
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|
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/** Set the name of the variable that is the assignment target */ |
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public void setVar(String var) |
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{ |
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this.var = var; |
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} |
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|
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/** Get the variable index for the variable that is the assignment target */ |
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public int getVarIndex() |
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{ |
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return index; |
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} |
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|
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// Setters |
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|
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/** Set the update expression */ |
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public void setExpression(Expression expr) |
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{ |
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this.expr = expr; |
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} |
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|
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/** Set the type of the update */ |
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public void setType(Type type) |
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{ |
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this.type = type; |
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} |
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|
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/** Set the ExpressionIdent corresponding to the variable name (for position information) */ |
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public void setVarIdent(ExpressionIdent ident) |
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{ |
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this.ident = ident; |
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this.var = ident.getName(); |
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} |
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|
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/** Set the variable index for the variable that is the assignment target */ |
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public void setVarIndex(int index) |
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{ |
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this.index = index; |
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} |
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|
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/** |
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* Execute this update element, based on variable values specified as a Values object, |
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* applying changes in variables to a second Values object. |
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* Values of any constants should also be provided. |
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* @param constantValues Values for constants |
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* @param oldValues Variable values in current state |
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* @param newValues Values object to apply changes to |
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*/ |
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public void update(Values constantValues, Values oldValues, Values newValues) throws PrismLangException |
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{ |
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newValues.setValue(var, expr.evaluate(constantValues, oldValues)); |
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} |
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|
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/** |
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* Execute this update element, based on variable values specified as a State object. |
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* It is assumed that any constants have already been defined. |
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* @param oldState Variable values in current state |
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* @param newState State object to apply changes to |
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*/ |
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public void update(State oldState, State newState) throws PrismLangException |
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{ |
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update(oldState, newState, false); |
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} |
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|
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/** |
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* Execute this update element, based on variable values specified as a State object. |
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* It is assumed that any constants have already been defined. |
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* @param oldState Variable values in current state |
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* @param newState State object to apply changes to |
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* @param exact evaluate arithmetic expressions exactly? |
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*/ |
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public void update(State oldState, State newState, boolean exact) throws PrismLangException |
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{ |
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Object newValue; |
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if (exact) { |
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BigRational r = expr.evaluateExact(oldState); |
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// cast to Java data type |
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newValue = expr.getType().castFromBigRational(r); |
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} else { |
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newValue = expr.evaluate(oldState); |
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} |
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newState.setValue(index, newValue); |
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} |
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|
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/** |
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* Check whether this update (from a particular state) would cause any errors, mainly variable overflows. |
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* Variable ranges are specified in the passed in VarList. |
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* Throws an exception if such an error occurs. |
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*/ |
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public void checkUpdate(State oldState, VarList varList) throws PrismLangException |
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{ |
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int valNew; |
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valNew = varList.encodeToInt(index, expr.evaluate(oldState)); |
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if (valNew < varList.getLow(index) || valNew > varList.getHigh(index)) |
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throw new PrismLangException("Value of variable " + var + " overflows", expr); |
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} |
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// Methods required for ASTElement: |
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@Override |
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public Object accept(ASTVisitor v) throws PrismLangException |
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{ |
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return v.visit(this); |
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} |
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@Override |
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public UpdateElement deepCopy() |
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{ |
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UpdateElement result = new UpdateElement((ExpressionIdent)ident.deepCopy(), expr.deepCopy()); |
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result.type = type; |
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result.index = index; |
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return result; |
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} |
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|
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// Other methods: |
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@Override |
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public String toString() |
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{ |
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return "(" + getVar() + "'=" + getExpression() + ")"; |
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} |
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} |
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