- Haskell-Cafe - Haskell.org

RE: computer language shootout
by Dejan Jelovic 30 Jul '01

30 Jul '01

Josef Svenningsson wrote: > Having said that I must also say that I think that ghc's I/O is fast > *enough*. It's just that it doesn't compare very well with other > languages. I've never had problems caused by slow I/O in Haskell. This is the favorite argument of proponents of slow languages ;). But as long as people wait for their computers (to boot up, to run a program, to compile a program, to do a computation, to...) speed is going to be a virtue. Dejan http://www.jelovic.com

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RE: computer language shootout
by Simon Marlow 30 Jul '01

30 Jul '01

> So am I. Have any haskell-performance gurus looked at any of > the code? Many of > the slowest entries are written in a very elegant, high-level > style that is > probably also relatively slow. I've looked at a few. The most common factor in the worst performers seems to be the performance of String-related operations. I tried converting a few to use PackedStrings but that didn't help much. I suspect our PackedString implementation could do with some tuning, and we could gain considerable benefit from having an hGetLinePS function (like hGetLine but gets a PackedString). Cheers, Simon

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RE: computer language shootout
by Simon Marlow 30 Jul '01

30 Jul '01

> On Mon, 30 Jul 2001, Simon Marlow wrote: > > > I've looked at a few. The most common factor in the worst > performers > > seems to be the performance of String-related operations. I tried > > converting a few to use PackedStrings but that didn't help much. I > > suspect our PackedString implementation could do with some > tuning, and > > we could gain considerable benefit from having an > hGetLinePS function > > (like hGetLine but gets a PackedString). > > > Well, I think the common factor is I/O. The lazy I/O seems to > be a real > bottleneck here. Trying to improve that would gain even more, I think. > I'm saying this because I did quite a bit of fiddling with some of the > examples (including trying PackedStrings). The conclusion I drew from > doing this was that the I/O performance was the problem. Agreed - I/O is indeed a bottleneck, but I believe it's the strings-as-lists-of-characters aspect of I/O rather than the lazy aspect that's the killer. Enclosed is a version of the spell-checker program that is about a factor of 3 faster than the one that Doug currently has; it uses PackedStrings and a home-grown hash table. The only down side is that it reads the entire input into a big PackedString before producing anything, and profiling suggests that it spends about half its time splitting the big string into lines. I think if I hack up an hGetLinePS I might be able to get another factor of 2 out of it. Cheers, Simon

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ST Questions
by Ashley Yakeley 28 Jul '01

28 Jul '01

Two questions on module ST: <http://www.haskell.org/ghc/docs/latest/set/sec-st.html> 1. What's the 's' parameter for? 2. Do STRefs get garbage-collected once they're forgotten? For instance, if I have an action that calls newSTRef, uses the ref, and then forgets it, and I run the action repeatedly, am I at risk of running out of memory? -- Ashley Yakeley, Seattle WA

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getCh
by Michael Ackerman 28 Jul '01

28 Jul '01

Hello, In Bird's book, p 332, he writes of a "Haskell primitive function, getCh, which is similar to getChar except that the character is not echoed". I can find no reference to getCh in the Report or the docs for the libraries. How can this be defined? Thanks. - Michael Ackerman

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Re: Simple compiler question
by Wolfgang Lux 26 Jul '01

26 Jul '01

Mark Carroll wrote > Do any of the decent Haskell compilers allow you to just type function > definitions at an interpreter prompt and use them in subsequent > interactions, as you'd expect from a Lisp environment? I don't know whether you consider hbi (the interactive version of hbc) a decent compiler, but it supports entering definitions as well: > let { f x = x + x }; f :: (Prelude.Num a) => a -> a > f 3; 6 Wolfgang -- Wolfgang Lux Phone: +49-251-83-38263 Institut fuer Wirtschaftinformatik FAX: +49-251-83-38259 Universitaet Muenster Email: wlux(a)uni-muenster.de

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Simple compiler question
by Mark Carroll 25 Jul '01

25 Jul '01

Do any of the decent Haskell compilers allow you to just type function definitions at an interpreter prompt and use them in subsequent interactions, as you'd expect from a Lisp environment? I'm fed up of editing a tiny file separately and typing :reload each time, etc. Surely I'm missing something obvious? -- Mark

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embeddable haskell?
by matt hellige 25 Jul '01

25 Jul '01

is there any haskell interpreter that allows haskell to be used as an embedded scripting language in a larger application, similar to the way python or tcl, but more especially guile (the gnu scheme implementation) are often used as extension languages? i thought i remembered hearing about some way in which hugs supported this, but i'm not sure and searches turn up nothing... in any event, this would be a useful thing to be able to do, and if it isn't currently possible, i'm wondering if there is a good reason for that, or if it's just that no one's ever undertaken to do it... matt -- matt hellige matt(a)immute.net http://matt.immute.net

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transfer
by Jan Skibinski 20 Jul '01

20 Jul '01

I'll be closing the www services of Numeric Quest soon for some time. I do not know yet when the pages will reappear again. If you need them they are all best indexed and backed-up by Google. Please do not download anything en-masse now - the server is just too slow for this. But you are still welcome to peruse. Hoping to "talk to you" again, Jan Skibinski Numeric Quest Inc. Huntsville, Ontario, Canada

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Fwd: STRAW POLL: comp.lang.haskell (fwd)
by Ashley Yakeley 19 Jul '01

19 Jul '01

If it were to be gatewayed to a list, Haskell Cafe seems the obvious choice. ---------------- Begin Forwarded Message ---------------- Date: 2001-07-19 09:24 Received: 2001-07-19 15:40 From: Mark Carroll, markc(a)chiark.greenend.org.uk To: Haskell List, haskell(a)haskell.org People should be aware of this article that was recently posted to the newsgroup comp.lang.functional. ------- start of forwarded message ------- From: jeff-haskell(a)litech.org (Jeffrey M. Vinocur) Newsgroups: comp.lang.functional,news.groups Subject: STRAW POLL: comp.lang.haskell Date: Thu, 19 Jul 2001 15:31:05 +0000 (UTC) Message-ID: <9j6ufp$fil$3(a)marduk.litech.org> I'm volunteering to take a straw poll to see whether we should try proposing comp.lang.haskell as a new newsgroup, possibly gatewayed to a mailing list. Currently Haskell-related traffic is in comp.lang.functional, and some people feel that it is a sufficiently-large portion of the traffic there to warrant a separate group. Opinions should be sent to <jeff-haskell(a)litech.org>. What we're really trying to determine is how many people would respond to an eventual Call For Votes in news.groups. There would first be a discussion period to hash out the details of things like mailing list gatewaying. (There is some discussion going on in comp.lang.haskell at the moment, feel free to join in there.) Reasonable choices for opinions are "Yes", "No", "Yes, provided it's gatewayed to a mailing list", "Yes, provided it's not gatewayed to a mailing list", "Will abstain from voting but don't want it gatewayed to the mailing list", etc. Note that a perfectly rational justification for wanting a separate group is because you read comp.lang.functional and want the Haskell traffic elsewhere; you need not be interested in reading a Haskell-only group. I'll post a summary of results, mmm, early next week, perhaps. So please reply promptly. -- Jeffrey M. Vinocur jeff(a)litech.org ------- end of forwarded message ------- _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell ----------------- End Forwarded Message ----------------- -- Ashley Yakeley, Seattle WA

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