Proposal: pare down traversable

David Feuer david.feuer at
Sat Sep 26 21:05:37 UTC 2015

Traversable currently has traverse, sequenceA, sequence, and mapM methods.
sequence and mapM seem to be dinosaurs now. I'd like to suggest that
sequenceA be turned into a deprecated function and mapM be moved from
Control.Monad to Data.Traversable and re-exported from Control.Monad.

I expect most instance declarations to survive unchanged. The only CPP pain
point will be that instances that define sequenceA will have to define
sequence instead.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the Libraries mailing list