On Sun, 21 Oct 2007, Twan van Laarhoven wrote:
Ashley Yakeley wrote:
3. There might be another useful class that's a subclass of Category and a superclass of Arrow, that essentially includes first but not arr. If someone wants to name it and define it, we can put it in the class hierarchy.
My proposal would be the following. The important things are that: 1. It incorporates Conal's deep arrow, 2. as well as everything that is needed for functional references/lenses and bijective/invertible functions. I have chosen to reuse prelude names where possible.
Looks good to me. CategoryPair is what I had in mind. -- flippa@flippac.org "I think you mean Philippa. I believe Phillipa is the one from an alternate universe, who has a beard and programs in BASIC, using only gotos for control flow." -- Anton van Straaten on Lambda the Ultimate