Отправлено с iPhone
Oct 7, 2010, в 21:03, Peter Wortmann <sc...@leeds.ac.uk> написал(а): > > On Tue, 2010-10-05 at 17:10 -0700, Evan Laforge wrote: >> +1 for something to solve the "dummy <- m; case dummy of" problem. >> Here are the possibilities I can think of: > > Might be off-topic here, but I have wondered for a while why Haskell > doesn't support something like follows: > > do case (<- m) of ... I think it'd be better to write just 'case (<- m) of', without 'do'. > > With the more general rule being: > > do ... e (<- m) g > => > ... m >>= \tmp -> e tmp g > > Reasons: > * "<-" is already "sugary", and the transformation is similar. Just > removes the need for the user to define a throw-away name. > * Better than liftMX and the Applicative operators. As shown, this is > more flexible while requiring less magic operators as a bonus. Also > makes more clear where the sides effects actually are. > * Goes well with the spirit of getting the good parts of imperative > coding where it potentially makes the code more concise. Can be > abused, obviously, but I have also seen a lot of code that I feel > could be written better using this. > > Anything I am overlooking here? I tried to find a discussion about > something like this, but didn't really know what to look for... > > Greetings, > Peter Wortmann > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe@haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
