/// <summary>
/// Resolves the given element in this scope.
/// </summary>
/// <param name="elem">The element.</param>
/// <param name="isFirst">Is the element the first one in the list.</param>
/// <returns>Resolved value or null</returns>
public object ResolveInScopes(object elem, bool isFirst)
{
object result;
// try to access the cached function value (speed optimization)
LispVariant elemAsVariant = elem as LispVariant;
if (elemAsVariant != null && elemAsVariant.CachedFunction != null)
{
return(elemAsVariant.CachedFunction);
}
var name = elem.ToString();
LispScope foundClosureScope;
// first try to resolve in this scope
if (TryGetValue(name, out result))
{
UpdateFunctionCache(elemAsVariant, result, isFirst);
}
// then try to resolve in global scope
else if (GlobalScope != null &&
GlobalScope.TryGetValue(name, out result))
{
UpdateFunctionCache(elemAsVariant, result, isFirst);
}
// then try to resolve in closure chain scope(s)
else if (IsInClosureChain(name, out foundClosureScope, out result))
{
UpdateFunctionCache(elemAsVariant, result, isFirst);
}
// then try to resolve in scope of loaded modules
else if (LispEnvironment.IsInModules(name, GlobalScope))
{
result = LispEnvironment.GetFunctionInModules(name, GlobalScope);
}
else
{
// activate this code if symbols must be resolved in parameter evaluation --> (println blub)
//if (elemAsVariant != null && elemAsVariant.IsSymbol && name != "fuellib")
//{
// throw new LispException($"Could not resolve symbol {name}");
//}
result = elem;
}
return(result);
}