/// <summary>
/// Provides the surface of this function if it has been statically defined
/// </summary>
/// <param name="context">the context used to create the surface</param>
/// <param name="xParam">The X axis of this surface</param>
/// <param name="yParam">The Y axis of this surface</param>
/// <returns>The surface which corresponds to this expression</returns>
public override Functions.Surface createSurface(Interpreter.InterpretationContext context, Parameter xParam, Parameter yParam)
{
Functions.Surface retVal = base.createSurface(context, xParam, yParam);
Functions.Surface surface = InitialValue.createSurface(context, xParam, yParam);
if (surface != null)
{
Values.ListValue value = ListExpression.GetValue(context) as Values.ListValue;
if (value != null)
{
int token = PrepareIteration(context);
AccumulatorVariable.Value = surface.Function;
foreach (Values.IValue v in value.Val)
{
if (v != EFSSystem.EmptyValue)
{
IteratorVariable.Value = v;
if (conditionSatisfied(context))
{
AccumulatorVariable.Value = IteratorExpression.GetValue(context);
}
}
NextIteration();
}
Functions.Function function = AccumulatorVariable.Value as Functions.Function;
if (function != null)
{
retVal = function.Surface;
}
else
{
throw new Exception("Expression does not reduces to a function");
}
EndIteration(context, token);
}
}
else
{
throw new Exception("Cannot create surface for initial value " + InitialValue.ToString());
}
retVal.XParameter = xParam;
retVal.YParameter = yParam;
return(retVal);
}