Use the New operator with a class by reference?

General
1

Is there a way to use the New operator with a variable class name?

Consider the following class hierarchy:

  • Fruit
  • ---- Orange
  • ---- Apple
  • ---- Grape
  • ---- etc…

Now, a random subclass of Fruit is created and stored in a Fruit variable.

In a method in the Fruit class, we need to make more of the same class. Something like this:

[code]function MakeAnotherFruitJustLikeThisOne(myFruit as Fruit)

dim newFruit as Fruit
newFruit = New [i]<SubclassOf_myFruit>[/i]

...

endfunc[/code]

And here is my problem. In the Fruit class, when I’m given a random Fruit object that will actually be some subclass of Fruit, I need to make more of the same object. Yes, I could have a switch statement that does a bunch of IsA and figures out which Fruit subclass I’ve actually been given, but I’m looking for a method that is more introspection based. I’d prefer the language to be able to figure this out without having to maintain a manual list of the possible subclasses in a big switch/IsA statement.

Any ideas?

2

Create a NewInstance method and override it in each subclass. Better, have it raise a GetNewInstance event in each subclass. In the event, you return a new instance of that subclass. Your code would only have to do

dim newFruit as Fruit = oldFruit.NewInstance()
3

use instropection to get type of the object you have, look for it’s constructor and call it to make new one?

4

And if there are several constructors then which one do you invoke ?

Introspection gets used for all kinds of things where its really not the right answer