Re: [Haskell-cafe] symbol type?

On Tue, Oct 09, 2007 at 11:28:08PM -0700, Michael Vanier wrote: > Is there an implementation of a symbol type in Haskell i.e. a string which > has a constant-time comparison operation? Yes, I beleive GHC uses one (utils/FastString.lhs iirs) Stefan signature.asc Description: Digital signature _

[Haskell-cafe] symbol type?

Is there an implementation of a symbol type in Haskell i.e. a string which has a constant-time comparison operation? Mike ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] help!!!! install HaskellDirect

Hello :) Someone knows like installing HDirect 1,2 in Windows XP with cygwin? , and that version of GHC is the one that uses???.Thank you for its collaboration Sule ;) _ News, entertainment and everything you care a

[Haskell-cafe] help!!!! install HakellDirect

Hello :) Someone knows like installing HDirect 1,2 in Windows XP with cygwin? , and that version of GHC is the one that uses???.Thank you for its collaboration Sule ;) _ Invite your mail contacts to join your friend

Re: [Haskell-cafe] Manual constructor specialization

Johan Tibell wrote: I have a rope data type [...] Perhaps you should talk to Derek Elkins about his. It would be nice if we had fewer, more canonical implementations of popular data structures, instead of a proliferation of half bakery. http://www.haskell.org/mailman/listinfo/haske

Re: [Haskell-cafe] pi

On 10/9/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > Yes, sorry, I slipped... I was so against the acos(-1) /or atan(...)/ > solution, that I wrote anything... +1, Honest -- Dan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.hask

Re: [Haskell-cafe] pi

Dan Piponi writes: jerzy.karczmarczuk wrote: So, you assume that acos should have a *default* implementation in the Floating class? Propose it, please. I don't think the proposal makes any such assumption. It implies only that *if* you provide acos, pi will be provided for you automatically i

[Haskell-cafe] Re: New slogan... (A long speculation)

ok writes: On 9 Oct 2007, at 9:10 am, [EMAIL PROTECTED] wrote: / I cited some arguments of our neighbours promoting imperative languages / the FLs condition the young minds in a way we do not appreciate. The only empirical evidence I'm aware of about this comes from Monash University ...

[Haskell-cafe] Re: New slogan for haskell.org

Andrew Coppin wrote: > Where do you guys find so many strange cat pictures?! You don't know any cats or cat owners, do you? ;) -- Alex Tarkovsky ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-caf

Re: [Haskell-cafe] Re: New slogan... (A long speculation)

On 9 Oct 2007, at 9:10 am, [EMAIL PROTECTED] wrote: * Scheme is very different from what we practice (C++, Fortran, etc., you know the song...) It may slow down the *adaptation* of students. They *will need* all that imperative stuff you hate. But, as a first language, the FLs condition the

Re: [Haskell-cafe] pi

On 10/9/07, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > So, you assume that acos should have a *default* implementation in the > Floating class? Propose it, please. I don't think the proposal makes any such assumption. It implies only that *if* you provide acos, pi will be provided for you auto

Re: [Haskell-cafe] pi

Or 4*atan 1. But yes, I agree that there could have been a default definition. But omitting it seems reasonable too. On 10/9/07, Jonathan Cast <[EMAIL PROTECTED]> wrote: > > On Tue, 2007-10-09 at 13:07 -0700, Don Stewart wrote: > > jonathanccast: > > > I just noticed that pi doesn't have a defaul

Re: [Haskell-cafe] pi

Jonathan Cast reacts to Don Stewart statement about PI: It's in the Floating class. Yes. But it doesn't have a default implementation. That strikes me as odd, considering the mathematical and actual correctness of class Floating sigma where pi = acos (-1) ... So, you assume that a

Re: [Haskell-cafe] pi

On Tue, 2007-10-09 at 13:07 -0700, Don Stewart wrote: > jonathanccast: > > I just noticed that pi doesn't have a default definition in the standard > > prelude, according to the Haddock docs. Why is this? > > $ ghci > Prelude> :t pi > pi :: (Floating a) => a > > Prelude> pi >

Re: [Haskell-cafe] Re: New slogan for haskell.org

On 10/9/07, Andrew Coppin <[EMAIL PROTECTED]> wrote: > > Brent Yorgey wrote: > > On 10/9/07, *Henning Thielemann* <[EMAIL PROTECTED] > > > wrote: > > > > > > I wish concat or concatMap :-) > > > > > > ask and ye shall receive! =) > > > > http://wso.williams.edu/~byorge

Re: [Haskell-cafe] Re: New slogan for haskell.org

Brent Yorgey wrote: On 10/9/07, *Henning Thielemann* <[EMAIL PROTECTED] > wrote: I wish concat or concatMap :-) ask and ye shall receive! =) http://wso.williams.edu/~byorgey/concatMap.png Where do you guys f

Re: [Haskell-cafe] Re: New slogan for haskell.org

On 10/9/07, Henning Thielemann <[EMAIL PROTECTED]> wrote: > > > On Tue, 9 Oct 2007, Alex Tarkovsky wrote: > > > Brent Yorgey wrote: > >> Aren't you going to make one featuring a "catamorphism"? =) > > > > Done, thanks for the contribution! ;) > > I wish concat or concatMap :-) ask and ye shall re

Re: [Haskell-cafe] Re: New slogan for haskell.org

On 09/10/2007, Alex Tarkovsky <[EMAIL PROTECTED]> wrote: > Brent Yorgey wrote: > > Aren't you going to make one featuring a "catamorphism"? =) > > Done, thanks for the contribution! ;) Goes to look... ...oh, very impressive! ;-) Lolcats seem to have reached a terrifying new nadir. D. ___

Re: [Haskell-cafe] pi

jonathanccast: > I just noticed that pi doesn't have a default definition in the standard > prelude, according to the Haddock docs. Why is this? $ ghci Prelude> :t pi pi :: (Floating a) => a Prelude> pi 3.141592653589793 It's in the Floating class. -- Don _

[Haskell-cafe] pi

I just noticed that pi doesn't have a default definition in the standard prelude, according to the Haddock docs. Why is this? jcc ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Re: New slogan for haskell.org

On Tue, 9 Oct 2007, Alex Tarkovsky wrote: Brent Yorgey wrote: Aren't you going to make one featuring a "catamorphism"? =) Done, thanks for the contribution! ;) I wish concat or concatMap :-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org

Re: [Haskell-cafe] New slogan for haskell.org

Henning Thielemann wrote: In my experience only the other way round works: Let people use C, Perl and Python until they find their programs unmaintainable. Then they will become interested in style and discipline and programming languages which _support_ good style. Perhaps this could be the

Re: [Haskell-cafe] Manual constructor specialization

A GADT version seems to generate OK code: data Top data NTop data Rope t where Empty :: Rope Top Leaf :: Rope NTop Node :: !(Rope NTop) -> !(Rope NTop) -> Rope NTop index :: Rope t -> Int -> Word8 index Empty _ = error "empty" index Leaf _ = error "leaf" index (Node l r) n = index'

[Haskell-cafe] Re: New slogan for haskell.org

Brent Yorgey wrote: > Aren't you going to make one featuring a "catamorphism"? =) Done, thanks for the contribution! ;) -- Alex Tarkovsky ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] ANNOUNCE: binary 0.4: high performance, pure binary parsing and serialisation

duncan.coutts: > In message <[EMAIL PROTECTED]> Don Stewart > <[EMAIL PROTECTED]> writes: > > ketil: > > > Don Stewart <[EMAIL PROTECTED]> writes: > > > > > > > The main thing is porting to ghc 6.8 -- which means the new (*faster*) > > > > lazy bytestring representation, and the smp parallel quick

Re: [Haskell-cafe] ANNOUNCE: binary 0.4: high performance, pure binary parsing and serialisation

In message <[EMAIL PROTECTED]> Don Stewart <[EMAIL PROTECTED]> writes: > ketil: > > Don Stewart <[EMAIL PROTECTED]> writes: > > > > > The main thing is porting to ghc 6.8 -- which means the new (*faster*) > > > lazy bytestring representation, and the smp parallel quickcheck driver > > > for the te

[Haskell-cafe] Re: Manual constructor specialization

Johan Tibell wrote: > On 10/9/07, David Benbennick <[EMAIL PROTECTED]> wrote: >> On 10/9/07, Johan Tibell <[EMAIL PROTECTED]> wrote: >>> data Rope = Empty >>> | Leaf >>> | Node !Rope !Rope >>> The point is that Empty >>> can only appear at the top by construction >> How about in

Re: [Haskell-cafe] Manual constructor specialization

On Tue, 2007-10-09 at 17:40 +0200, Johan Tibell wrote: > On 10/9/07, David Benbennick <[EMAIL PROTECTED]> wrote: > > On 10/9/07, Johan Tibell <[EMAIL PROTECTED]> wrote: > > > data Rope = Empty > > > | Leaf > > > | Node !Rope !Rope > > > > > The point is that Empty > > > can only

RE: [Haskell-cafe] New slogan for haskell.org

Yep, I totally agree. At our school, we're teaching the students assembly language, starting with 8-bit 6502 assembly :-) -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Henning Thielemann Sent: Tuesday, October 09, 2007 10:06 AM To: Derek Elkins Cc: has

Re: [Haskell-cafe] Manual constructor specialization

On 10/9/07, David Benbennick <[EMAIL PROTECTED]> wrote: > On 10/9/07, Johan Tibell <[EMAIL PROTECTED]> wrote: > > data Rope = Empty > > | Leaf > > | Node !Rope !Rope > > > The point is that Empty > > can only appear at the top by construction > > How about indicating this in you

Re: [Haskell-cafe] Manual constructor specialization

On 10/9/07, Johan Tibell <[EMAIL PROTECTED]> wrote: > data Rope = Empty > | Leaf > | Node !Rope !Rope > The point is that Empty > can only appear at the top by construction How about indicating this in your data type? I.e., data Rope = Empty | NonEmptyRope data NonEmptyRope

[Haskell-cafe] Manual constructor specialization

I have a rope data type with the invariant that one of its data constructors can never appear as a leaf. module Data.Rope where import Data.Word (Word8) data Rope = Empty | Leaf | Node !Rope !Rope index :: Rope -> Int -> Word8 index Empty _ = error "empty" index Leaf _

[Haskell-cafe] Re: Haskell FFI and finalizers

Simon Marlow wrote: > Maxime Henrion wrote: > >Stefan O'Rear wrote: > >>On Thu, Oct 04, 2007 at 12:55:41AM +0200, Maxime Henrion wrote: > >>>When writing the binding for foo_new(), I need to open a file with > >>>fopen() to pass it the FILE *. Then I get a struct foo * that I can > >>>easily assoc

Re: [Haskell-cafe] ANNOUNCE: binary 0.4: high performance, pure binary parsing and serialisation

ketil: > Don Stewart <[EMAIL PROTECTED]> writes: > > > The main thing is porting to ghc 6.8 -- which means the new (*faster*) > > lazy bytestring representation, and the smp parallel quickcheck driver > > for the testsuite (it'll use N cores, watch the jobs migrate around). > > Binary 0.4 seems t

[Haskell-cafe] Re: Haskell FFI and finalizers

Maxime Henrion wrote: Stefan O'Rear wrote: On Thu, Oct 04, 2007 at 12:55:41AM +0200, Maxime Henrion wrote: When writing the binding for foo_new(), I need to open a file with fopen() to pass it the FILE *. Then I get a struct foo * that I can easily associate the the foo_destroy() finalizer. H

Re: [Haskell-cafe] Re: New slogan for haskell.org

On 10/8/07, Alex Tarkovsky <[EMAIL PROTECTED]> wrote: > > Alex Tarkovsky wrote: > > Brandon S. Allbery KF8NH wrote: > >> I can has English? :) > > > > This comment inspired what could be either the beginning of an > > infectious Haskell recruitment campaign, or just a sign that some of us > > are

[Haskell-cafe] Re: Some lambda identities

I wrote: > And flip is (essentially) the B combinator. Oops, the C combinator. -Yitz ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Re: Some lambda identities

I wrote: > While playing with @pl on #haskell, I noticed some > weird and surprising lambda identities. For example: > let {c = (.); c4 = c c c c} > Then we have: > c c4 == c c4 c c c c > You get a lot more interesting stuff when you > throw flip into the mix. > Anyone know more about these things?

Re: [Haskell-cafe] EnableGUI hack changes working directory

apfelmus wrote: > Is there a way to automate ghci ... EnableGUI -framework Carbon and > typing enableGUI at the first prompt? I have the following in my .ghci file: -- Read GHCI commands from the file whose name is -- in the GHCIRC environment variable :def _load const(System.Environment.get

[Haskell-cafe] Re: unsafePerformIO: are we safe?

Jorge Marques Pelizzoni wrote: Hi, all! This is a newbie question: I sort of understand what unsafePerformIO does but I don't quite get its consequences. In short: how safe can one be in face of it? I mean, conceptually, it allows any Haskell function to have side effects just as in any imperati

[Haskell-cafe] Some lambda identities

While playing with @pl on #haskell, I noticed some weird and surprising lambda identities. For example: let {c = (.); c4 = c c c c} Then we have: c c4 == c c4 c c c c Proof: Repeatedly apply the identity: (*) x (y z) == c x y z More stuff: c c2 == c4, c c3 == c7, but c cn does not appear to be

[Haskell-cafe] EnableGUI hack changes working directory

Hello, the EnableGUI hack for getting a window in GHCi on Mac OS X (10.3.9 for me) unexpectedly changes the working directory for the running ghci [...] apfelmus$ ghci -i../../Hackage/SOE/src [...] GHC Interactive, version 6.6.1, for Haskell 98. *Main> :! pwd /Users/apfelmus/Documents/Programm

Re: [Haskell-cafe] New slogan for haskell.org

On Mon, 8 Oct 2007, Derek Elkins wrote: On Mon, 2007-10-08 at 20:54 +1000, Thomas Conway wrote: I must say, I get that! but at the same time, of course, the high level abstraction is exactly what *we* love about Haskell. Then they should teach assembly not Python. In fact, I'd recommend as