Formal proposal: replace Data.List.inits

Joachim Breitner mail at
Sat Sep 6 17:28:35 UTC 2014


Am Freitag, den 05.09.2014, 18:07 -0400 schrieb David Feuer:
> The problem I was seeing with initsQ2 was caused by a bad interaction
> of different things fusing badly. It seems relatively unlikely that
> the underlying issues with list fusion will be resolved by the next
> GHC release, so we need to decide what to do about that. Some options,
> from my favorite to my least favorite:
> 1. Use the fusing scanl', but mark inits NOINLINE. The proposed
> implementation wouldn't really wouldn't be such a hot fusion prospect
> in any case. The only interesting sort of fusion I see is (concat .
> inits), which we *could* implement with a special rule, but no one
> else seems to think it's worth the trouble.
This seems to be a good way forward. This way, we get a faster inits in,
and can then consider the issue of fusing separately.


Joachim “nomeata” Breitner
  mail at joachim-breitner.de
  Jabber: nomeata at  • GPG-Key: 0xF0FBF51F
  Debian Developer: nomeata at

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