public bool TryGetFunction(string functionName, out bool isUserFunction, out FunctionHandler retHandler)
{
//First, check user functions to see if function with name exists
if(userFunctions.Contains(functionName))
{
retHandler = new UserFunctionHandler();
isUserFunction = true;
return true;
}
//Then, check system functions to see if function exists
if (this.systemFunctions.TryGetValue(functionName, out FunctionHandler systemFunction))
{
retHandler = systemFunction;
isUserFunction = false;
return true;
}
//Finally, check if function has been overridden, if it has a '_' at the front ('_' prefixed function
if(functionName.StartsWith("_") &&
this.systemFunctions.TryGetValue(functionName.Substring(1), out FunctionHandler overridenFunction))
{
retHandler = overridenFunction;
isUserFunction = false;
return true;
}
retHandler = null;
isUserFunction = false;
return false;
}
private void RegisterFunctionWithCheck(IgnoreCaseDictionary<FunctionHandler> dict, FunctionHandler userFunctionHandler)
{
foreach (string function_name in userFunctionHandler.FunctionNames())
{
if (dict.Contains(function_name))
{
throw new Exception($"User function {function_name} was defined twice");
}
else
{
dict.Set(function_name, userFunctionHandler);
}
}
}
