/// <summary>
/// Turn expression symbols into lookups of elements on the current item. Attribute must use a function (GetAttribute) due to the need to specify a name.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void ProcessSymbol(object sender, SymbolEventArgs e)
{
if (currentItem == null)
{
// cant process any symbols if there's nothing to process them on!
e.Status = SymbolStatus.UndefinedSymbol;
return;
}
if (Enum.GetNames(typeof(ItemsChoiceType)).Contains(e.Name) && currentItem.ItemsElementName.Contains((ItemsChoiceType)Enum.Parse(typeof(ItemsChoiceType), e.Name)))
{
e.Result = Convert.ToDouble(currentItem.GetSingleItemByEnum((ItemsChoiceType)Enum.Parse(typeof(ItemsChoiceType), e.Name)));
}
else if (currentItem.ItemsElementName.Contains(ItemsChoiceType.Attribute) && e.Name.StartsWith("Attribute_", StringComparison.CurrentCulture))
{
var attribute = e.Name.Substring(10);
e.Result = currentItem.GetAttribute(attribute) == null ? 0 : evaluator.Execute(currentItem.GetAttribute(attribute).value);
}
// Unknown symbol name
else
{
e.Status = SymbolStatus.UndefinedSymbol;
}
}
/// <summary>
/// This method evaluates a symbol name and returns its value.
/// </summary>
/// <param name="name">Name of symbol</param>
/// <param name="pos">Position at start of symbol</param>
/// <returns></returns>
protected double EvaluateSymbol(string name, int pos)
{
double result = default(double);
// We found a symbol reference
SymbolStatus status = SymbolStatus.UndefinedSymbol;
if (ProcessSymbol != null)
{
SymbolEventArgs args = new SymbolEventArgs();
args.Name = name;
args.Result = result;
args.Status = SymbolStatus.OK;
ProcessSymbol(this, args);
result = args.Result;
status = args.Status;
}
if (status == SymbolStatus.UndefinedSymbol)
{
throw new EvalException(String.Format(ErrUndefinedSymbol, name), pos);
}
return(result);
}
/// <summary>
/// This method evaluates a symbol name and returns its value.
/// </summary>
/// <param name="name">Name of symbol</param>
/// <param name="pos">Position at start of symbol</param>
/// <returns></returns>
protected double EvaluateSymbol(string name, int pos) {
double result = default(double);
// We found a symbol reference
SymbolStatus status = SymbolStatus.UndefinedSymbol;
if(ProcessSymbol != null) {
SymbolEventArgs args = new SymbolEventArgs();
args.Name = name;
args.Result = result;
args.Status = SymbolStatus.OK;
ProcessSymbol(this, args);
result = args.Result;
status = args.Status;
}
if(status == SymbolStatus.UndefinedSymbol)
throw new EvalException(String.Format(ErrUndefinedSymbol, name), pos);
return result;
}
