/// <summary>
/// Resolves a provided reference of forms "X" or "X.Y" and passes back the first given or
/// derivation which matches.
/// </summary>
/// <param name="reference">The string reference for the given or derivative</param>
/// <returns>An IValue representing either the given or derivation the reference points to.</returns>
internal IValue ResolveReference(string reference, string ElementScope)
{
//Find near givens with a full reference first.
IValue val = Givens.Find(t => t.Key == ElementScope + "." + reference);
if (val == null)
{
//Ok, try near givens with a partial reference
val = Givens.Find(t => t.Key == reference);
}
//Ok, givens exhausted; find me a derivation with that reference.
if (val == null)
{
string[] references = reference.Split('.');
Element el = Elements.Find(t => t.ElementName == references[0]);
if (el == null)
{
throw new ArgumentException("Unable to reference expression element");
}
val = el.Derivations.Find(t => t.Name == references[1]);
}
return(val);
}