[Haskell-cafe] Is there a library that has a strict version of `sum`?

Tom Ellis tom-lists-haskell-cafe-2017 at jaguarpaw.co.uk
Wed Aug 15 05:40:33 UTC 2018


On Tue, Aug 14, 2018 at 08:50:01PM +0200, Damian Nadales wrote:
> On Tue, Aug 14, 2018 at 8:08 PM Bryan Richter <b at chreekat.net> wrote:
> > On 08/14/2018 11:22 AM, Damian Nadales wrote:
> > is there something wrong with sum in particular?
>
> From the point of view of somebody that is not that bright, like myself,
> it seems. Why would you need to build a huge thunk containing the
> representation of a sum of values. It is not that you can pattern match on
> integers or consume the sum incrementally.
> 
> I apologize if I infuriate people, but I really don't get the usefulness of
> a lazy sum function.
>
> > More generally, why isn't sum working for you?
>
> Because if I want to test my function with 100000000 values it consumes a
> lot of memory.

Your rationale seems utterly reasonable and I'm surprised that you've even
been asked to provide it.  Everyone knows the problems with lazy sum.  I'm
actually astonished (and sorry) about the pushback you've received here. 
Having easy access to a sum function that doesn't blow up and *not* having
easy access to one that does seem self evidently worthwhile.

Tom


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