Proposal: unify constant functors

wren ng thornton wren at
Sun May 6 02:36:27 CEST 2012

On 5/4/12 10:44 AM, Andreas Abel wrote:
> open import Data.Functor.Constant renaming (Constant to K)
> Maybe that could be a feature of future Haskell as well?

I would love such a feature. Not just for bikeshedding disputes, but as 
an alternative to qualified imports for when you're intentionally using 
different things with conflicting names.

Seems like it should be easy enough to implement too (sayeth he who 
hasn't hacked on GHC). The real difficulty methinks would be in 
specifying the module import syntax, since there's a conflict between 
(1) creating a coherent integrated system for qualified, unqualified, 
renamed, explicit, and hidden imports (plus any other features we want 
to add at the same time); and (2) backwards compatibility.

Live well,

More information about the Libraries mailing list