[Haskell-cafe] A functional programming solution for Mr and Mrs Hollingberry

[Richard O'Keefe]

On 26/05/2012, at 4:16 AM, David Turner wrote:
> 
> I don't. I think the trouble is that classes don't add value in exercises of this size.

This was the key point, I think.
In this example, there wasn't any significant behaviour that could be moved
to superclasses.  For that matter, whether a supplier is plain, preferred,
or problematic is, one hopes, not a *permanent* property of a supplier.

Sometimes higher-order functions can substitute for classes.