On 2006-08-18 at 17:30+0200 "John Hughes" wrote: > > From: 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.
so publishers should love it! ;-) > 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. It depends over how long a time you amortise the cost. I've heard that when people complained about the problems of having tab significant in makefiles, no correction was made because there were about a dozen users. We're farther on than that, but still at a stage where the population of users is not that large, and the users are flexible. So I think we should be reasonably bold about these things. To reinforce what Aaron said, if a programme works now, it'll still work if map suddenly means fmap. Jón -- Jón Fairbairn Jon.Fairbairn at cl.cam.ac.uk _______________________________________________ Haskell-prime mailing list Haskell-prime@haskell.org http://www.haskell.org/mailman/listinfo/haskell-prime