[Haskell-cafe] proper way to generate a random data in criterion

Gregory Collins greg at gregorycollins.net
Wed Oct 19 21:21:48 CEST 2011

On Wed, Oct 19, 2011 at 5:03 PM, Johan Tibell <johan.tibell at gmail.com> wrote:
> It does. You need to use evaluate to have ensure actually be evaluated.

I'm almost certain you're wrong about this. The bang pattern on the
return from ensure (!r1 <- ensure $ ...) forces r1 to WHNF, which goes
through deepseq, and thus the whole list is forced. See
https://gist.github.com/1299380 for a short counterexample.

Gregory Collins <greg at gregorycollins.net>

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