On 2006-08-18, John Hughes <[EMAIL PROTECTED]> wrote: > Jon Fairbairn <[EMAIL PROTECTED]> >> A reasonable choice (forestalling the objection that using >> List.map, listMap or mapList would be too distracting for >> students) would be >> >> lmap:: (t -> t') -> [t] -> [t'] >> map:: Functor f => (t -> t') -> f t -> f t' >> > > I'd prefer mapList to lmap, to be honest--at least the connection between > the name > and the type is clear. But remember, this would at a stroke make Haskell' > incompatible with all existing Haskell textbooks. Even if publishers brought > out new editions, even if we told students to buy them, there are many, many > second hand books in circulation, and it would be years before one could > rely > on students having Haskell' books. All that time, students would write map > instead of mapList because that's what the book says, and get stuck with > incomprehensible error messages. Is it really worth an incompatible change > in the library functions used by all beginners, just to rename fmap to map? > It seems to me that the gain from a change is very small, and the cost > considerable.
But list is a functor, so it should work. They just get harder error messages, when their programs are wrong. Let's work on the error messages, not keeping the language harder to understand for more general programs. -- Aaron Denney -><- _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime
