Re: [Haskell-cafe] List concat

G'day all. Quoting Andrew Coppin <[EMAIL PROTECTED]>: The function (++) :: [x] -> [x] -> [x] has O(n) complexity. That's not entirely true. When you call (++), it does O(1) work. If you evaluate k cons cells. it takes O(min(k,n)) work. Cheers, Andrew Bromage ___

Re: [Haskell-cafe] GHC predictability

As a beginner, I had found the behaviour quite unpredictable. But with time I found that I could reason out the behaviour with my slowly growing knowledge of laziness. I don't spot all the places in my program that will suck while writing a program, but post facto many things become clear. (And the

Re: [Haskell-cafe] Maybe a, The Rationale

On 2008 May 11, at 22:42, Don Stewart wrote: ok: Maybe types force you to deal with it, while simultaneously providing convenience functions to help you deal with it. I readily grant that Maybe is a wonderful wonderful thing and I use it freely and voluntarily. BUT it should not dominate

Re: [Haskell-cafe] Maybe a, The Rationale

ok: > > Maybe types force you to deal with it, while simultaneously > >providing convenience functions to help you deal with it. > > I readily grant that Maybe is a wonderful wonderful thing and I use it > freely and > voluntarily. BUT it should not dominate the code. > > Consider Haskell's

Re: [Haskell-cafe] Maybe a, The Rationale

On 12 May 2008, at 1:52 am, Brandon S. Allbery KF8NH wrote: My real point was that in the C programming culture it was/is far too common to use an in-band value; that is, one that could be confused with or treated as a valid response: null pointers, stdio's EOF (= -1). Here I must disagre

Re: [Haskell-cafe] Re: Interesting critique of OCaml

On 9 May 2008, at 6:59 am, Donnie Jones wrote: I pasted a copy of the article below for those that cannot access the site.Why Ocaml Sucks Published by Brian at 6:49 pm under Functional Languages: Ocaml, Haskell . An even better idea [for 'printf'] might be some variant of functional un

Re: [Haskell-cafe] haskell compiler on NetBSD amd64

donn: > On Sat, 10 May 2008 23:59:18 +0200 > Matthias Kilian <[EMAIL PROTECTED]> wrote: > > > > Here you go: > > > > http://openbsd.dead-parrot.de/distfiles/ghc-6.6.1-amd64-unknown-openbsd-hc.tar.bz2 > > Thanks, I have managed to build a stage1/ghc-6.6.1 with those, > which is a start even if it

Re: [Haskell-cafe] saner shootout programs

jhc0033: > On Sun, May 11, 2008 at 1:40 PM, Don Stewart <[EMAIL PROTECTED]> wrote: > > > n-body requires updating a global array of double values to be > > I think the array and any side-effects on it can and should be local > to the simulation procedure. > > > competitive performance-wise, thou

Re: [Haskell-cafe] saner shootout programs

On Sun, May 11, 2008 at 1:40 PM, Don Stewart <[EMAIL PROTECTED]> wrote: > n-body requires updating a global array of double values to be I think the array and any side-effects on it can and should be local to the simulation procedure. > competitive performance-wise, though we haven't really nail

Re: [Haskell-cafe] saner shootout programs

I don't know Haskell very well, but Paul: "I'm not racist but . . ." :-) even I can tell, looking at, for example, the N-body benchmark, that the Haskell code is probably not type-safe, and the tricks used in it would not be usable in a larger program (see below). The task is esse

Re: [Haskell-cafe] saner shootout programs

dons: > jhc0033: > > I don't know Haskell very well, but even I can tell, looking at, for > > example, the N-body benchmark, that the Haskell code is probably not > > type-safe, and the tricks used in it would not be usable in a larger > > program (see below). > > > > The task is essentially a pur

Re: [Haskell-cafe] saner shootout programs

jhc0033: > I don't know Haskell very well, but even I can tell, looking at, for > example, the N-body benchmark, that the Haskell code is probably not > type-safe, and the tricks used in it would not be usable in a larger > program (see below). > > The task is essentially a pure computation: take

[Haskell-cafe] saner shootout programs

I don't know Haskell very well, but even I can tell, looking at, for example, the N-body benchmark, that the Haskell code is probably not type-safe, and the tricks used in it would not be usable in a larger program (see below). The task is essentially a pure computation: take a list of bodies havi

[Haskell-cafe] Re: dropping hyphens and \n in words

"Chaddaï Fouché" <[EMAIL PROTECTED]> wrote: > 2008/5/11 Achim Schneider <[EMAIL PROTECTED]>: > > Excuse my bluntness, but I utterly fail to make sense of this. > > Reformulating your understanding of it would surely be beneficial. > > He has a routine that gives him a list of words classified b

Re: [Haskell-cafe] Re: dropping hyphens and \n in words

2008/5/11 Achim Schneider <[EMAIL PROTECTED]>: > Excuse my bluntness, but I utterly fail to make sense of this. > Reformulating your understanding of it would surely be beneficial. He has a routine that gives him a list of words classified by line, and he want the hyphens to be accounted for. So

Re: [Haskell-cafe] haskell compiler on NetBSD amd64

On Sat, 10 May 2008 23:59:18 +0200 Matthias Kilian <[EMAIL PROTECTED]> wrote: > > Here you go: > > http://openbsd.dead-parrot.de/distfiles/ghc-6.6.1-amd64-unknown-openbsd-hc.tar.bz2 Thanks, I have managed to build a stage1/ghc-6.6.1 with those, which is a start even if it does immediately core d

Re: [Haskell-cafe] haskell compiler on NetBSD amd64

kili: > On Sat, May 10, 2008 at 03:03:39PM -0700, Don Stewart wrote: > > > I've to admit that the ghc port for OpenBSD is a little bit weird ;-) > > > > > > (but not as weird as my current work on ghc-6.8 for OpenBSD) > > > > What's your plan for the OpenBSD port, Kili? > > * Proper bootstrappin

[Haskell-cafe] Re: dropping hyphens and \n in words

Ivan Amarquaye <[EMAIL PROTECTED]> wrote: > > Generally a hyphen is written at the end of the sentance when moving > on to the next line and i managed to achieve this in haskell by using > the "\n"- newline which places an index word in the next line i.e. if > the words appear indexed like this..

[Haskell-cafe] ANN: xmonad-utils 0.1

Just dropping in a quick note: I've uploaded to Hackage the 0.1 release of xmonad-utils here: . There is of course a Darcs repo available as well: . What is xmonad-utils? It's a

Re: [Haskell-cafe] dropping hyphens and \n in words

On 2008 May 11, at 11:47, Ivan Amarquaye wrote: Now my problem is this...I'm assuming that the hyphen normally comes at the end of a sentence like this: "there are so many guys ravis- hing our women" and this can be demonstrated in haskell by "\n" which places the words or characters follow

[Haskell-cafe] dropping hyphens and \n in words

Generally a hyphen is written at the end of the sentance when moving on to the next line and i managed to achieve this in haskell by using the "\n"- newline which places an index word in the next line i.e. if the words appear indexed like this...([1]),[mangoes] and a hyphen is applied, it becom

Re: [Haskell-cafe] Re: Couple of formal questions

On Mon, May 5, 2008 at 9:53 AM, Wouter Swierstra <[EMAIL PROTECTED]> wrote: > > On 1 May 2008, at 16:58, Michael Karcher wrote: > > Wouter Swierstra <[EMAIL PROTECTED]> wrote: > > > > > Hi Creighton, > > > > > > > Where could I find a proof that the initial algebras & final > > > > coalgebras of

Re: [Haskell-cafe] Copy on read

> Uniqueness typing does not lead to in-place update. If a value is > only used once, then there is no need to update it at all! my understanding is that if a value is uniquely-typed then it is statically known never to have more than one reference, thus it can be modified in-place. Some poten

Re: [Haskell-cafe] Maybe a, The Rationale

On 2008 May 11, at 5:09, PR Stanley wrote: Um, I was encountering and recognizing times when I really needed an out-of-band "null", and the pain of representing such in C, shortly after I started serious programming in C (call it 1984-5). Is this really difficult? Paul: Hm

Re: Cryptographic hash uniquness (was [Haskell-cafe] Simple network client)

Graham Klyne wrote: This is a very late response ... but I did some calculations as part of some work I did a while ago: http://www.ietf.org/rfc/rfc2938.txt (See appendix A "The birthday paradox") #g A memorable summary of the birthday paradox being : There is a 50% chance of a collision w

Re: Cryptographic hash uniquness (was [Haskell-cafe] Simple network client)

This is a very late response ... but I did some calculations as part of some work I did a while ago: http://www.ietf.org/rfc/rfc2938.txt (See appendix A "The birthday paradox") #g -- Peter Verswyvelen wrote: winds up having a write cache, which is mutable in practice. The interesting thing

Re: [Haskell-cafe] Error: Improperly terminated character constant

Single quotes are for characters, double quotes are for strings. So change 'es' to "es". -- Johannes Laire 2008/5/11 Ivan Amarquaye <[EMAIL PROTECTED]>: > > > I'm writing a function dRop to accept words ending in 'es' and drop the last > two characters i.e. 'es'.eg. mangoes -> mongo but i keep o

[Haskell-cafe] Error: Improperly terminated character constant

I'm writing a function dRop to accept words ending in 'es' and drop the last two characters i.e. 'es'.eg. mangoes -> mongo but i keep on getting this error: "Improperly terminated character constant" after running this code which i have left below. Can i get any form of help from anyone in here

Re: [Haskell-cafe] Newbie Question: Using Haskell Functions in a C Program

On Thu, May 8, 2008 at 5:09 PM, Philip Müller <[EMAIL PROTECTED]> wrote: > Thanks for all the answers. I'm testing this right now and simples cases > work as expected. However from what I've read it seems it'll get ugly once I > try to pass a C array to a Haskell function. > > Well, maybe arrays i

Re[2]: [Haskell-cafe] Re: Order of Evaluation

Hello Luke, Sunday, May 11, 2008, 1:24:04 PM, you wrote: > So.. what do you use unsafePerformIO together with? when i call function that in general case depends on the execution order (so it's type is ...->IO x), but in my specific case it doesn't matter. typical example is hGetContents on confi

Re: [Haskell-cafe] haskell compiler on NetBSD amd64

On Sat, May 10, 2008 at 03:03:39PM -0700, Don Stewart wrote: > > I've to admit that the ghc port for OpenBSD is a little bit weird ;-) > > > > (but not as weird as my current work on ghc-6.8 for OpenBSD) > > What's your plan for the OpenBSD port, Kili? * Proper bootstrapping from .hc files. * T

Re: [Haskell-cafe] Order of Evaluation

Miguel Mitrofanov wrote: As I understand it Haskell does not specify an order of evaluation and it would therefore be a mistake to write a program which relies on a particular evaluation order. This is the 'unsafe' aspect of unsafePerformIO. Hmm... IMHO unsafePerformIO is 'unsafe' because it ca

Re: [Haskell-cafe] Re: Order of Evaluation

On Fri, May 9, 2008 at 3:46 PM, Achim Schneider <[EMAIL PROTECTED]> wrote: > Miguel Mitrofanov <[EMAIL PROTECTED]> wrote: > > > Oh, you sure? > > > I was, until you wrote that. But then, I am, as I wouldn't use > unsafePerformIO together with IORef's, it's giving me the creeps. So.. what do yo

Re: [Haskell-cafe] Stack vs Heap allocation

2008/5/10 Edsko de Vries <[EMAIL PROTECTED]>: >> The key reason why nested additions take stack space, is because (+) on >> Integers is *strict* in both arguments. If it were somehow non-strict >> instead, then the unevaluated parts of the number would be heap-allocated >> rather than stack-alloca

Re: [Haskell-cafe] Maybe a, The Rationale

Um, I was encountering and recognizing times when I really needed an out-of-band "null", and the pain of representing such in C, shortly after I started serious programming in C (call it 1984-5). Is this really difficult? Paul: Hmm, I'm not quite sure what you're driving at.

Re: [Haskell-cafe] Maybe a, The Rationale

PR Stanley <[EMAIL PROTECTED]> writes: > What is the underlying rationale for the Maybe data type? It is the equivalent of a database field that can be NULL. > is it the safe style of programming it encourages/ Yes. Consider C, where this is typically done with a NULL pointer, or Lisp,