[Haskell-beginners] Foldable for (,)

[amindfv at gmail.com]

> El 24 abr 2017, a las 03:20, David Thomas <davidleothomas at gmail.com> escribió:
> 
> One thing that's been missed in this discussion is that constraints
> can propagate.
> 
> Of course no one is wanting to pass something they know is a tuple
> into a function they know is length.  But a function that expects
> something Foldable might want to know length or sum, and it might be
> reasonable to call that function on a tuple.
> 

Do you have a real-world example of a case where that's useful, and difficult to achieve in another (non-Foldable) way?

Genuinely asking, so that when we talk about what's gained/lost we have something concrete to talk about.

Tom



> On Sun, Apr 23, 2017 at 11:52 PM, Jonathon Delgado
> <voldermort at hotmail.com> wrote:
>> 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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