public Completion Assign(ExecutionEnvironment enviroment, object value)
{
if (value != null && !(value is LinkedListEx))
{
return(Completion.Exception("value is not a linked list type", this));
}
if (Node == null)
{
return(Completion.Exception("Null Exception", this));
}
if ((Node is Identifier))
{
string var = (Node as Identifier).Variable;
if (!enviroment.HasValue(var))
{
return(Completion.Exception("varaible was not defined", Node));
}
LinkedListEx tree = enviroment.GetValue(var) as LinkedListEx;
if (tree == null)
{
return(Completion.Exception("variable is not linked list", Node));
}
tree.Previous = value as LinkedListEx;
return(new Completion(value));
}
else
{
var c = Node.Execute(enviroment);
if (!c.IsValue)
{
return(c);
}
if (c.ReturnValue is LinkedListEx)
{
(c.ReturnValue as LinkedListEx).Previous = value as LinkedListEx;
return(new Completion(value));
}
else
{
return(Completion.Exception("value is not linked list", Node));
}
}
}
protected override Completion ExecuteImpl(ExecutionEnvironment enviroment)
{
if (Node == null)
{
return(Completion.Exception("Null Exception", this));
}
if (Node is Identifier)
{
string var = (Node as Identifier).Variable;
if (!enviroment.HasValue(var))
{
return(Completion.Exception("varaible was not defined", Node));
}
LinkedListEx tree = enviroment.GetValue(var) as LinkedListEx;
if (tree == null)
{
return(Completion.Exception("variable is not linked list", Node));
}
return(new Completion(tree.Previous));
}
else
{
var c = Node.Execute(enviroment);
if (!c.IsValue)
{
return(c);
}
if (c.ReturnValue is LinkedListEx)
{
return(new Completion((c.ReturnValue as LinkedListEx).Previous));
}
else
{
return(Completion.Exception("value is not linked list", Node));
}
}
}