[Haskell-cafe] Collection of objects?

[Donn Cave]

On Fri, 17 Nov 2006, Valentin Gjorgjioski wrote:
...
> But I need something which is heterogeneous and non-fixed length. I'm 
> used do Java, and this switch to functional languages is very strange to 
> me. So, to be clear, I need something like LinkedList<Object> in java.

I looked in a couple of on-line tutorials, thinking I would quickly
find something about this, but -- maybe in my haste I missed something.
Objective CAML documentation gets right to it, I wonder if we're assuming
prior exposure to strongly typed functional languages?

Anyway, you need to define a type that accounts for the types you
want to support -

  data Object = IntObject Int | StringObject String

  objectString :: Object -> String
  objectString (IntObject v) = show v
  objectString (StringObject v) = v

  main = mapM (putStrLn . objectString) [(IntObject 7), (StringObject "eight")]

	Donn Cave, donn at drizzle.com