Adding support for lens type classes

[tmcgilchrist]

Would you consider adding or accepting a PR to add lens type class support?
eg Prism, Iso

[chessai]

Yes, I would.

[andrewthad]

Laws for all lawful typeclasses are welcome so long as they come with a manual flag that can be used to disable their them (the flags are needed because primitive's test suite uses quickcheck-classes, and the extra deps would make travis take a long time).

[chessai]

Yes, thanks for mentioning that @andrewthad. However I think you thought that this was quickcheck-classes when you made that comment.

The same does apply here though: All laws from typeclasses external to base need: a flag that toggled their status as a build dependency, a cpp-option "HAVE_${PACKAGENAME}", and for the library/test suite only to build the Laws/tests for the associated typeclass (using the CPP).

[andrewthad]

Yep, my bad. I was thinking of the wrong repo.

[kozross]

It's be nice to have this for the optics versions too.

[jkachmar]

It looks like there's a project that implements some hedeghog checkers for the optics library: https://github.com/typeclasses/hedgehog-optics/blob/master/hedgehog-optics/src/Hedgehog/Optics.hs