Brandon S. Allbery KF8NH wrote:
On Jul 8, 2007, at 8:12 , Andrew Coppin wrote:
Aye, you drive a car without knowing how it works - but it was put together by some people who *do* know these things. Would you drive a car you built yourself? ;-)
No :) --- but depending on what you're doing, you can use rank-2 types without knowing what's under the hood. In fact, I'd say the fact that you're using them is evidence of that.
(Aside --- looking at your problem description, I wonder if GADTs would be a better fit.)
Oh, I don't mind not knowing how rank-2 types are *implemented*. ;-) But it would be nice to know what they *are*... :-S (Thus far, they just seem to be some incomprehensible syntax that makes the compiler stop complaining. In particular, I have no idea what the difference between rank-2, rank-N and existentially quantified is...)