[Haskell-cafe] Language extensions

[Andrew Coppin]

David House wrote:
> I've read through pretty much all your arguments, and I think they
> boil down to this:
>
> "I don't understand why X is useful, and therefore it can't be useful."

I meant to imply more that "it's very difficult to understand why it's 
useful". If an extension were truely *useless*, I doubt those guys at 
GHC would have bothered spending years implementing them.

Most of the documents that describe these things begin with "suppose we 
have this extremely complicated and difficult to understand situation... 
now, we want to do X, but the type system won't let us." Which makes it 
seem like these extensions are only useful in extremely complicated and 
rare situations. The fact that my own programs hardly ever result in 
situations where I want to do X but the type system won't let me only 
reinforces this idea. Maybe it's just the kind of code I write...

> Moreover, if you've ever written a full-sized Haskell program you'd
> probably find a use case for at least one of these extensions.

...or the fact that I only write trivial applications...

(Well, they're not trivial to me. But I imagine everybody else would 
think them trivial.)