Add Lens as a Category.

[gusty]

No description provided.

[mausch]

Actually, the latest Haskell lens package composes lens with the standard function composition operator from the Prelude (previous implementations had to use the generalized composition from Category). ( https://github.com/ekmett/lens/wiki/Overview ).
I need to look deeper into its implementation (which seems quite complex!). It may be possible to port this quite directly with the tools FsControl provides.

[gusty]

Profunctor, Arrow, MonadState, Comonad?
True, that's not straightforward.
A good exercise with no doubt.

[gusty]

Implemented !
Not as complete as the one in the link but it's just a matter of adding more functions and some more types.