On Fri, Nov 30, 2012 at 6:48 PM, Henning Thielemann <lemming@henning-thielemann.de> wrote:

On Fri, 30 Nov 2012, Edward Kmett wrote:

You can add lens to the list of packages that had to define their own (for doctest purposes). ;)

I grepped for isLeft and isRight in lens-3.6 but did not find them.

It is used in Projection tests in the as yet unreleased 3.7 on github.

src/Control/Lens/Projection.hs:-- >>> let isLeft  (Left  _) = True; isLeft  _ = False

-Edward