maintaining pre-AMP+FTP-Prelude in external package

Felipe Lessa felipe.lessa at
Thu May 14 02:20:25 UTC 2015

On 13-05-2015 19:12, Herbert Valerio Riedel wrote:
> On 2015-05-13 at 16:38:14 +0200, Henning Thielemann wrote:
>> I am only concerned with exported identifiers. Monad class would
>> remain a sub-class of Applicative, but Applicative is not exported by
>> PreludePreAMP.
> But then you won't be able to define Monad instances... :-/

Just import Applicative from its own module, like we did before GHC 7.10.

AFAIU, the point of having PreludePreAMP would be facilitating
maintenance of code that works both on 7.10 and <= 7.8 without warnings.
 One would still need to know that for defining a Monad they need
Applicative.  That was the best practice for a long time, anyway.



-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 819 bytes
Desc: OpenPGP digital signature
URL: <>

More information about the Libraries mailing list