Functor, Applicative, Monad, Foldable, Traversable instances for (, , ) a b

[Jon Fairbairn]

Tony Morris <tonymorris at gmail.com> writes:

> I don't think it is the "appropriate" set. It's an example. 0 is in the
> set of integers. The value 0 is in many sets.

OK, so I clearly do not understand your argument. The
implication I took from “and 0 is not an integer” is that the
foldable instance for ((,) a) should be present because it is
the zero case of something that has integers as its domain, and
I wanted to know what that something is.  If this was not the
intention of your argument, what was?

-- 
Jón Fairbairn                                 Jon.Fairbairn at cl.cam.ac.uk
http://www.chaos.org.uk/~jf/Stuff-I-dont-want.html  (updated 2014-04-05)