[Haskell-beginners] Foldable for (,)

Tony Morris tmorris at tmorris.net
Mon Apr 24 10:30:54 UTC 2017

I only know that the length of any forall a. ((,) a) is going to be one.
When it is polymorphic, I don't know that it is ((,) a) although it might
be at the call site, and so I don't know the length.

On Mon, Apr 24, 2017 at 4:52 PM, Jonathon Delgado <voldermort at hotmail.com>

> Tony Morris - please could you give a (practical) example of code where
> the a tuple could realistically be passed to length, but you don't know
> what the answer will be at compile time?
> Michael Orlitzky - everything in .NET has to descend from Object because
> of it's OO design. Why does tuple have to implement Foldable if it doesn't
> provide any useful functions?
> Thank you very much everyone in this thread for helping me understand!
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