My message was written too hastily, sorry about that.
The example Alexey asked is exactly what the ApplicativeDo proposal[1] uses
as motivation. The point of it is that you shouldn't need to care about
writing applicative or do-style, when the behavior differs the most
efficient one can be used.
Though as it stands the proposal seems to run into the problem of being
unintuitive like others mentioned since you need to enable an extension. A
type implementing this functionality would need to be documented as
"Enable ApplicativeDo when using this, or be very confused"
[1] https://ghc.haskell.org/trac/ghc/wiki/ApplicativeDo
- Adam
On Fri, May 1, 2015 at 2:00 PM, Ross Paterson
I agree that, now that we have AMP, applicative and monadic interfaces absolutely *should* match, and that it should be considered an error for
On Thu, Apr 30, 2015 at 10:11:49PM -0700, Andrew Gibiansky wrote: them
not to; semantically different interfaces can be provided with newtypes.
This requirement is in the documentation for both Applicative and Monad classes. (It's been in Applicative since 2010, and was added to Monad in the AMP release.) _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe