#haskell

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08:09:12 <rwbarton> haasn: for instance, just comparing "main = mapM_ print [1..10000000]" to a C program using printf, it is already only ~5 times slower
08:10:00 <albeit> Why "already only"? Is that faster than you would expect?
08:10:02 <vanila> Why is haskell so slow?
08:10:18 <rwbarton> I am just responding to <haasn> I guess for String, “only an order of magnitude” would count as “surprisingly efficient”
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08:10:34 <mmachenry1> vanila: Maybe Haskell just woke up.
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08:10:58 <Maior> vanila: do you just sit in channels to troll them? the Django stuff yesterday about the master/slave stuff was unsubtle
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08:11:16 <Maior> (for a flexible value of yesterday that means "some days in the recent past")
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08:11:41 <mmachenry> Maior: I guess I *was* born yesterday ;)
08:11:45 <napping> Is there an easy way to expand unicode ligature characters (I really just need "ff" and "ffi", guess I could hardcode them)
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08:12:09 <Maior> mmachenry: :P
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08:12:35 <napping> Data.Text.ICU.Normalize probably does it somehow
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08:14:20 <absence> has it been decided when the applicative monad proposal will hit ghc head? anytime soon, or closer to 7.10 release?
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08:15:40 <Maior> absence: ooh got a link handy?
08:15:51 <vanila> Maior: Since you're ignoring my PM I'll say it here: that was very rude and unfair of you
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08:16:31 <Maior> vanila: I have PMs from non-friends disabled
08:16:31 <ion> {-# LANGUAGE ffi #-}
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08:17:03 <Maior> vanila: meanwhile, I stand by it as a valid question from the data I have
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08:17:29 <vanila> Maior, move discussion to PM
08:17:40 <Maior> I'll pass
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08:19:20 <mmachenry> Maior: It's not really a valid question yet. I don't have your data and your question is underspecified. Unless I missed something which is possible, I lost network a moment ago.
08:19:27 <absence> Maior: http://www.haskell.org/haskellwiki/Functor-Applicative-Monad_Proposal
08:19:44 <ion> vanila: Pastebin your code and we can try to figure out why it’s too slow. Otherwise the question can only be answered with mu.
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08:19:59 <rwbarton> absence: there is no scheduling of when things hit GHC HEAD in my experience. either someone gets around to it, or not
08:20:10 <Maior> absence: cheers
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The whole “correctness proof” line is silly because *no one writes correctness proofs*. Real programs – programs that solve real problems – are generally large and complex enough that even if you’re using a language like Haskell, writing a correctness proof *still* isn’t practical. Sure, you can easily write a correctness proof for an implementation of a binary search tree in Haskell. You *can* write a correctness proof for that in, say, Java. But the Haskell proof will be easier and cleaner, and you’ll be able to trust the connection between the code and the proof much more than you could in Java. But really, a good set of tests – which you *should* be writing, whether you’re programming in Java, C, or Haskell – does as good a job of verifying the correctness of something simple like that. And for anything significantly more complicated than that, people just *don’t* write proofs. I’ve certainly *never* seen a correctness proof for a Haskell program, except in papers arguing about how provable correctness is in Haskell. (Does GHC have correctness proofs? I doubt it. It’s certainly had quite its share of bugs, which means that either it’s correctness isn’t proven, or the proof is wrong!)