[Haskell-cafe] curious about sum

Conal Elliott conal at conal.net
Sat Jun 13 13:23:45 EDT 2009


You can make numeric class instances from arbitrary Applicatives [1].  I
imagine a lot of them (e.g. Stream) would want at least some
non-strictness.  We might provide strict alternatives for sum and product.
I wonder what else.

[1]
http://hackage.haskell.org/cgi-bin/hackage-scripts/package/applicative-numbers

- Conal

On Sat, Jun 13, 2009 at 7:03 AM, Keith Sheppard <keithshep at gmail.com> wrote:

> Is there any reason that sum isn't strict? I can't think of any case
> where that is a good thing.
>
> Prelude> sum [0 .. 1000000]
> *** Exception: stack overflow
>
> -Keith
> --
> keithsheppard.name
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