public override void Visit(IdentifierExpression identifier)
{
if (Parameters.ContainsKey(identifier.Name))
{
// The parameter is defined in the dictionary
if (Parameters[identifier.Name] is Expression)
{
// The parameter is itself another Expression
var expression = (Expression)Parameters[identifier.Name];
// Overloads parameters
foreach (var p in Parameters)
{
expression.Parameters[p.Key] = p.Value;
}
expression.EvaluateFunction += EvaluateFunction;
expression.EvaluateParameter += EvaluateParameter;
Result = ((Expression)Parameters[identifier.Name]).Evaluate(flow);
}
else
{
Result = Parameters[identifier.Name];
}
}
else
{
// The parameter should be defined in a callback method
var args = new ParameterArgs();
// Calls external implementation
OnEvaluateParameter(identifier.Name, args);
if (!args.HasResult)
{
throw new ArgumentException("Parameter was not defined", identifier.Name);
}
Result = args.Result;
}
}
private void OnEvaluateParameter(string name, ParameterArgs args)
{
EvaluateParameter?.Invoke(flow, name, args);
}
