- Haskell-Cafe - Haskell.org

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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pipe through external process?
by John Meacham 17 Jul '01

17 Jul '01

I am trying to implement a function which takes a string, pipes it through an external command and returns the stdout of teh command utilizing the Posix library and ghc. first of all, if someone has this handy code tidbit already written then feel free to send it to me. the other thing is that I cannot figure out how to get data into and out of the process. I can create a pipe which returns a pair of Fd's but then i cannot pass these into runProcess since it expects handles. also I have no ability to wait for the termination of the command that runProcess starts... it is always possible i am just overlooking a few key functions in Posix... John -- --------------------------------------------------------------------------- John Meacham - California Institute of Technology, Alum. - john(a)repetae.net ---------------------------------------------------------------------------

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blindness people
by jiro hiraike 14 Jul '01

14 Jul '01

Dear Sirs, I am in Japanese university's(Rikkyo University in Tokyo) master course of mathmatics. And I am helping one blindness undergraduate student as part-time job. This is in the class of aplied mathmatics, and we use haskell to learn algorizm and so on. The problem is he (the blindness student) cannot use haskell in his home, becouse of his "reading-out-software" for blindness people. The school's reading-out-software "outSpoken" is available for haskell, but his one is not. So, I want to know the available reading out software. If you know, PLEASE tell me. Or some other information that you know, PLEASE tell me. Sincerly yours, jiro hiraike.

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Good for a laugh!
by Kirk 04 Jul '01

04 Jul '01

Thought you'd like to take a break and laugh a little. The following site is updated daily and has funny news articles, quotes, and sections like Dog Thoughts and Headlines. It even has a Webcam! I'm sure you'll find something to enjoy. http://www.laundryday.com Spread the smiles. P.S. Please do not respond to this email. It's a one time mailing. :-)

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Another space leak question
by Srineet 03 Jul '01

03 Jul '01

Hi, I have been having a problem for some time, maybe this is a simple obvious question, but I would like your help on this. I give only what I think is the crux of the problem, just to keep this mail short and avoid unnecessary details. Consider, step (n, x:xs) = step (n+x, xs) main' = step (1, repeat 1) I think, if you evaluate main', you'd run out of heap space (couldn't totally verify because my hugs crashed on my windows machine!). Now have another step' step' n (x:xs) | n == 0 = 0 | otherwise = step' (n+x) xs main'' = step' 1 (repeat 1) Now main'' continues forever, but doesn't cause hugs to run out of heap.What' the reason that, while both main' and main'' run forever, the first causes hugs to run out of heap while second doesn't. Thanks, bye. - Srineet.

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Re: Another space leak question
by Juan Carlos Arevalo Baeza 02 Jul '01

02 Jul '01

At 10:14 AM 7/2/2001 +0000, kahl(a)heraklit.informatik.unibw-muenchen.de wrote: >The reason is that the addition in step1 is deferred lazily, >since its result is never needed. >Therefore, unreduced additions accumulate. I just thought of a question for compiler/interpreter makers out there... Couldn't the garbage collector start doing reductions as soon as it can't free up enough heap? Like a second step in garbage collection. It'd need some simple heuristic to decide what to reduce, but in the end, Haskell being pure, the order of evaluations won't affect the result. Call it an emergency garbage collection step. Is there anything I'm missing that would make this not possible? Salutaciones, JCAB --------------------------------------------------------------------- Juan Carlos "JCAB" Arevalo Baeza | http://www.roningames.com Senior Technology Engineer | mailto:jcab@roningames.com Ronin Entertainment | ICQ: 101728263 (my opinions are only mine) JCAB's Rumblings is so off-line O:-(

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Another space leak questionth
by Srineet 01 Jul '01

01 Jul '01

Hi, I have been having a problem for some time, maybe this is a simple obvious question, but I would like your help on this. I give only what I think is the crux of the problem, just to keep this mail short and avoid unnecessary details. Consider, step (n, x:xs) = step (n+x, xs) main' = step (1, repeat 1) I think, if you evaluate main', you'd run out of heap space (couldn't totally verify because my hugs crashed on my windows machine!). Now have another step' step' n (x:xs) | n == 0 = 0 | otherwise = step' (n+x) xs main'' = step' 1 (repeat 1) Now main'' continues forever, but doesn't cause hugs to run out of heap.What' the reason that, while both main' and main'' run forever, the first causes hugs to run out of heap while second doesn't. Thanks, bye. - Srineet.

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Re: toEnum problem
by Michael Ackerman 29 Jun '01

29 Jun '01

Oops. Sorry for stupid question. Michael Ackerman Levent Erkok wrote: > > On Friday 29 June 2001 07:42 am, you wrote: > > Hello, > > > > I tried this: > > > > data Nat = Zero | Succ Nat > > > > instance Enum Nat where > > fromEnum Zero = 0 > > fromEnum (Succ n) = 1 + fromEnum n > > toEnum 0 = Zero > > toEnum n = if n > 0 then 1 + toEnum n > > else error "bah" > > Don't you actually mean: > > if n > 0 then Succ (toEnum n) else error "bah" > > in the last line? > > -Levent.

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Re: toEnum problem
by Ashley Yakeley 29 Jun '01

29 Jun '01

The error is here: At 2001-06-29 00:42, Michael Ackerman wrote: > toEnum n = if n > 0 then 1 + toEnum n ^^^^^^^^^^^^ (toEnum n) :: Nat, so you can't do (+) on it unless (Num Nat), because (+) is a member of the Num class. Obviously you want -- toEnum n = if n > 0 then Succ (toEnum n) else error "bah" -- -- Ashley Yakeley

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