Hi, 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. Greetings, Joachim
-- Joachim “nomeata” Breitner mail@joachim-breitner.de • http://www.joachim-breitner.de/ Jabber: nomeata@joachim-breitner.de • GPG-Key: 0xF0FBF51F Debian Developer: nomeata@debian.org