[Haskell-cafe] Side conditions on Data.Profunctor.Choice?

David Turner dct25-561bs at mythic-beasts.com
Sat Jan 31 08:31:20 UTC 2015


I was expecting to see coherence conditions for instances of
Data.Profunctor.Choice along the lines of:

dimap (either (Left . f) Right) id . right' === dimap id (either (Left
. f) Right) . right'

and similarly for left', but there's nothing like that in the docs.

Does anyone know whether (a) those conditions aren't true in general,
or (b) they are true but provable from other theorems so not worth

Many thanks,


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