Re: [Haskell-cafe] Comments from OCaml Hacker Brian Hurt

On Thu, 2009-01-15 at 18:10 -0500, Cale Gibbard wrote: > My personal preference would be: > > class Monoid m where >zero :: m >(++) :: m -> m -> m > > (in the Prelude of course) > > - Cale I've tried doing this (and making more widespread use of typeclassed operations) by writing my ow

Re: [Haskell-cafe] Re: Haskell and C++ program

On Mon, 2009-01-19 at 22:12 -0500, S. Doaitse Swierstra wrote: > On 17 jan 2009, at 22:22, Derek Elkins wrote: > > > On Thu, 2009-01-15 at 13:40 +0100, Apfelmus, Heinrich wrote: > >> Eugene Kirpichov wrote: > >>> Well, your program is not equivalent to the C++ version, since it > >>> doesn't bail

Re: [Haskell-cafe] Re: Haskell and C++ program

On 17 jan 2009, at 22:22, Derek Elkins wrote: On Thu, 2009-01-15 at 13:40 +0100, Apfelmus, Heinrich wrote: Eugene Kirpichov wrote: Well, your program is not equivalent to the C++ version, since it doesn't bail on incorrect input. Oops. That's because my assertion show . read = id is wro

Re: [Haskell-cafe] Re: Improved documentation for Bool

G'day all. I wrote: - Intuitionistic logic systems. - The "truth values" of an arbitrary topos (i.e. the points of the subobject classifier). Sorry, I misread the question. These are _not_ instances of Boolean (or at least the latter isn't an instance in general). Cheers, Andrew Bromage __

Re: [Haskell-cafe] Re: Improved documentation for Bool

G'day all. Quoting David Menendez : Are there any instances of Boolean that aren't isomorphic to Bool? Sure. Two obvious examples: - The lattice of subsets of a "universe" set, where "or" is union "and" is intersection and "not" is complement with respect to the universe. - Many-valued log

Re: [Haskell-cafe] Re: Improved documentation for Bool

On Mon, Jan 19, 2009 at 6:25 PM, David Menendez wrote: > Are there any instances of Boolean that aren't isomorphic to Bool? a->Bool for any a. I think. Though I think it should be called GeorgeBoolean otherwise we might confuse it for something his father might have invented. -- Dan ___

Re: [Haskell-cafe] Employment

> Such a database would help me counter by boss's > argument that "it's impossible to find and hire Haskell programmers." > Err, people actually say such things? And they say _we're_ out of touch with the real world? ___ Haskell-Cafe mailing list Haskell

Re: [Haskell-cafe] Re: Improved documentation for Bool

On Mon, Jan 19, 2009 at 7:22 PM, wrote: > > And perhaps more to the point, "Boolean" is an adjective, not a noun. > Therefore, it would be better reserved for a typeclass. There's also John Meacham's Boolean package. > class (Heyting a) => Boolean a

Re: [Haskell-cafe] Employment

On Mon, Jan 19, 2009 at 3:04 PM, Andrew Coppin wrote: > > Like many people I'm sure, I'd like to get paid to code stuff in Haskell. > But I can't begin to imagine how you go about doing that... At Eaton, we're using Haskell to design automotive control systems (see http://cufp.galois.com/). In a

[Haskell-cafe] GHCi Memory Leak in Windows Vista

Hi all! Environment: Windows Vista + SP1, GHC 6.10.1. Description: If use ghci.exe and run separate ghc.exe compiler process, memory leak in ghci occurred. After exhausting available memory Vista has no responding. Steps for reproduce: 1) After run GHCi, process list has 2 processes: ghci.

Re: [Haskell-cafe] know a workaround for greedy context reduction?

I revisited the Strongly typed Heterogeneous Lists paper and read about the import hierarchy technique. The basic idea is to delay importing the instances until as late as possible, which prevents the context simplification. The instances are effectively imported in the top, Main module. I'm think

Re: [Haskell-cafe] LinuxFest Northwest 2009

I might go - I'll certainly keep an eye on the page. It would be more likely if I could find a group driving from Portland. Tom On Mon, Jan 19, 2009 at 9:25 PM, Shachaf Ben-Kiki wrote: > LFNW 2009 () is going to be at the end of > April, and I was wondering if an

Re: [Haskell-cafe] Re: Improved documentation for Bool

G'day all. On Mon, 2009-01-19 at 19:33 +, Andrew Coppin wrote: My only problem with it is that it's called Bool, while every other programming language on Earth calls it Boolean. (Or at least, the languages that *have* a name for it...) Jonathan Cast commented: Except C++? And perhaps

Re: [Haskell-cafe] Employment

> Hmm, interesting... So lots happening in Portland, Oregon. Lots in > Cambridge, MA. A few things in Europe. And nothing at all in the UK... Nothing in the UK? Lets not forget MSR and Well-Typed! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org h

Re: [Haskell-cafe] MonadTrans lift implementation

G'day all. Quoting Jonathan Cast : (By the way, you *do* have the equations lift (return x) = return x [...] Right. And you could, at least in principle, implement "return" this way in all monad transformers. Cheers, Andrew Bromage ___ Haskel

[Haskell-cafe] Current research on overlapping/closed type families?

What's the status of overlapping/closed type families? I'm interested in something like the following, which can currently be implemented in GHC with Oleg-magic using functional dependencies, but cannot, to my knowledge, be implemented with type families: data HTrue = HTrue data HFalse = HFalse

Re: [Haskell-cafe] Re: How to make code least strict?

Actually, I see a nice pattern here for unamb + pattern matching: > zip xs ys = foldr unamb undefined [p1 xs ys, p2 xs ys, p3 xs ys] where > p1 [] _ = [] > p2 _ [] = [] > p3 (x:xs) (y:ys) = (x,y) : zip xs ys Basically, split each pattern out into a separate function (which by definiti

Re: [Haskell-cafe] xhtml + bytestring

I think that your instance is too specific, although useful for the particular case of escaping. I've done my own implementation for fun: concatMap' :: (Word8 -> L.ByteString) -> L.ByteString -> L.ByteString concatMap' f s = L.unfoldr p x0 where x0 = (LI.Empty, s, 0, 0) p (LI.Empty,

Re: [Haskell-cafe] Re: Improved documentation for Bool

On Mon, 2009-01-19 at 20:55 +, Andrew Coppin wrote: > Dan Piponi wrote: > > On Mon, Jan 19, 2009 at 11:33 AM, Andrew Coppin > > wrote: > > > > > >> My only problem with it is that it's called Bool, while every other > >> programming language on Earth calls it Boolean. (Or at least, the lang

Re: [Haskell-cafe] Employment

On Mon, 2009-01-19 at 21:04 +, Andrew Coppin wrote: > Erik de Castro Lopo wrote: > > Its proabably a little harder to find a company that wants a > > Haskell hacker than it is to find a company where Haskell and > > other sane languages can be worked in over time. > > > > I think you're p

Re: [Haskell-cafe] Re: How to make code least strict?

I second Ryan's recommendation of using unamb [1,2,3] to give you unbiased (symmetric) laziness. The zip definition could also be written as zip xs@(x:xs') ys@(y:ys') = assuming (xs == []) [] `unamb` assuming (ys == []) [] `unamb` (x,y) : zip xs' ys' The 'assuming' function

RE: [Haskell-cafe] Employment

Andrew Coppin wrote: > Andrew Wagner wrote: >> http://www.haskell.org/haskellwiki/Haskell_in_industry could be of >> interest to you > > Hmm, interesting... So lots happening in Portland, Oregon. Lots in > Cambridge, MA. A few things in Europe. And nothing at all in the > UK... We (Credit Suiss

Re: [Haskell-cafe] GLUT (glutGet undefined reference)

2009/1/19 Paul Keir : > I was hoping to introduce my old pal OpenGL > with my new chum, Haskell. I used cabal to > install GLUT on my 64-bit Ubuntu machine with > GHC 6.8.2 (installed via apt-get/synaptic). I'm sorry, I can't help you with your problem. But I'd recommend you using GLFW, it's a lot

Re: [Haskell-cafe] Employment

Andrew Wagner wrote: http://www.haskell.org/haskellwiki/Haskell_in_industry could be of interest to you Hmm, interesting... So lots happening in Portland, Oregon. Lots in Cambridge, MA. A few things in Europe. And nothing at all in the UK... ___ Ha

Re: [Haskell-cafe] Employment

Erik de Castro Lopo wrote: Its proabably a little harder to find a company that wants a Haskell hacker than it is to find a company where Haskell and other sane languages can be worked in over time. I think you're probably right about that. ;-) I mean, heck, *I* use Haskell at work - and

Re: [Haskell-cafe] Re: Improved documentation for Bool

Dan Piponi wrote: On Mon, Jan 19, 2009 at 11:33 AM, Andrew Coppin wrote: My only problem with it is that it's called Bool, while every other programming language on Earth calls it Boolean. (Or at least, the languages that *have* a name for it...) Python: bool ocaml: bool C++: bool C9

[Haskell-cafe] xhtml + bytestring

Hi Bjorn, hi list, the darcswatch instance I’m running is getting quite big, and it periodically slows down my server. I managed to get quite an improvement with this simple patch to my parsing: http://darcs.nomeata.de/cgi-bin/darcsweb.cgi?r=darcswatch;a=commitdiff;h=20090119181919-23c07-140f8deb9

Re: [Haskell-cafe] Factoring into type classes

On Mon, 2009-01-19 at 12:10 -0800, Iavor Diatchki wrote: > Hi, > > On Mon, Jan 19, 2009 at 11:06 AM, Jonathan Cast > wrote: > > On Mon, 2009-01-19 at 10:59 -0800, Iavor Diatchki wrote: > >> Hello, > >> The multitude of newtypes in the Monoid module are a good indication > >> that the Monoid class

Re: [Haskell-cafe] MonadTrans lift implementation

On Mon, 2009-01-19 at 21:31 +, Ross Paterson wrote: > On Mon, Jan 19, 2009 at 01:13:37PM -0800, Jonathan Cast wrote: > > (On the other hand, your hunch that lift = return is correct --- so you > > get a cookie for that; it's just that return here is neither the return > > of the monad for m nor

Re: [Haskell-cafe] GLUT (glutGet undefined reference)

Ouch. Sorry, I misread your post: I thought you were having troubles on Windows. 2009/1/20 Eugene Kirpichov : > Have you tried > http://netsuperbrain.com/blog/posts/freeglut-windows-hopengl-hglut/ > ? > > 2009/1/20 Paul Keir : >> Hi all, >> >> I was hoping to introduce my old pal OpenGL >> with m

Re: [Haskell-cafe] GLUT (glutGet undefined reference)

Have you tried http://netsuperbrain.com/blog/posts/freeglut-windows-hopengl-hglut/ ? 2009/1/20 Paul Keir : > Hi all, > > I was hoping to introduce my old pal OpenGL > with my new chum, Haskell. I used cabal to > install GLUT on my 64-bit Ubuntu machine with > GHC 6.8.2 (installed via apt-get/syna

[Haskell-cafe] GLUT (glutGet undefined reference)

Hi all, I was hoping to introduce my old pal OpenGL with my new chum, Haskell. I used cabal to install GLUT on my 64-bit Ubuntu machine with GHC 6.8.2 (installed via apt-get/synaptic). I followed the wiki OpenGLTutorial1 until: ghc -package GLUT HelloWorld.hs -o HelloWorld at which point my scree

Re: [Haskell-cafe] MonadTrans lift implementation

On Mon, Jan 19, 2009 at 01:13:37PM -0800, Jonathan Cast wrote: > (On the other hand, your hunch that lift = return is correct --- so you > get a cookie for that; it's just that return here is neither the return > of the monad for m nor the return of the monad for ReaderT m. It is, > instead, the r

[Haskell-cafe] LinuxFest Northwest 2009

LFNW 2009 () is going to be at the end of April, and I was wondering if anyone here is going to be there, or possibly a Haskell-related presentation. Last year I met ac from #haskell there, but it would be nice if more people came, especially with the (relatively) b

Re: [Haskell-cafe] MonadTrans lift implementation

On Mon, 2009-01-19 at 13:03 -0800, Daryoush Mehrtash wrote: > Is there a reason why the lift function in ReaderT's MonadTrans instance is > implemented as: > > instance MonadTrans (ReaderT r) where > > lift m = ReaderT $ \_ -> m > > > > Instead of just using the monad's return function?

Re: [Haskell-cafe] MonadTrans lift implementation

On Mon, Jan 19, 2009 at 01:03:55PM -0800, Daryoush Mehrtash wrote: > lift m = ReaderT $ \_ -> m > return a = ReaderT $ \_ -> return a If you look carefully you will see that these are not the same. -Brent ___ Haskell-Cafe mailing list Haskell

[Haskell-cafe] MonadTrans lift implementation

Is there a reason why the lift function in ReaderT's MonadTrans instance is implemented as: instance MonadTrans (ReaderT r) where lift m = ReaderT $ \_ -> m Instead of just using the monad's return function? Could "lift m" be implemented as "return m"? instance (Monad m) => Monad (Rea

Re: [Haskell-cafe] Employment

Andrew Coppin wrote: > Is it possible to earn money using Haskell? Does anybody here actually > do this? > > Inquiring minds want to know... ;-) I work for a company that designs, builds, and sells lawn mowers (hustlerturf.com). We use quite a bit of Haskell, especially as a "glue language" for

Re: [Haskell-cafe] Factoring into type classes

I'd prefer something like Sum :: Monoid Integer Sum = Monoid {mappend = (+), mempty = 0} Prod :: Monoid Integer Prod = Monoid {mappend = (*), mempty = 1} instance Sum in [some code using mempty and mappend] On 19 Jan 2009, at 23:18, Alberto G. Corona wrote: This is one of the shortcomings of

Re: [Haskell-cafe] Employment

Haskell's all I use at work, although no-one requires it. I know that Ravi Nanavati's company uses Haskell pretty exclusively, and there's also Galois and a couple of financial houses. I was pretty impressed with the professional turnout for ICFP 2008. -- Jeff On Mon, Jan 19, 2009 at 2:34 PM, A

[Haskell-cafe] Haskell Weekly News: Issue 101 - January 19, 2009

--- Haskell Weekly News http://sequence.complete.org/hwn/20090119 Issue 101 - January 19, 2009 --- Welcome to issue 101 of HWN, a newsletter covering

Re: [Haskell-cafe] Factoring into type classes

On Mon, 2009-01-19 at 21:18 +0100, Alberto G. Corona wrote: > This is one of the shortcomings of haskell not to mention other > programming languages. Mathemathicist would find it very annoying. > > > Instead of > > > instance Monoid Integer where > mappend = (+) > mempty = 0 > > inst

Re: [Haskell-cafe] Factoring into type classes

On Mon, 2009-01-19 at 12:10 -0800, Iavor Diatchki wrote: > >> I usually > >> avoid using the "newtype" trick as I find it inconvenient: usually > >> the newtype does not have the same operations as the underlying type > >> and so it cannot be used directly, and if you are going to wrap thing > >>

Re: [Haskell-cafe] Re: Improved documentation for Bool

On Mon, Jan 19, 2009 at 11:33 AM, Andrew Coppin wrote: > My only problem with it is that it's called Bool, while every other > programming language on Earth calls it Boolean. (Or at least, the languages > that *have* a name for it...) Python: bool ocaml: bool C++: bool C99: bool C#: bool > But

Re: [Haskell-cafe] Re: How to make code least strict?

On Mon, Jan 19, 2009 at 9:10 AM, ChrisK wrote: > Consider that the order of pattern matching can matter as well, the simplest > common case being zip: > > zip xs [] = [] > zip [] ys = [] > zip (x:xs) (y:ys) = (x,y) : zip xs ys If you are obsessive about least-strictness and performance isn't a gi

Re: [Haskell-cafe] Factoring into type classes

This is one of the shortcomings of haskell not to mention other programming languages. Mathemathicist would find it very annoying. Instead of instance Monoid Integer where mappend = (+) mempty = 0 instance Monoid Integer where mappend = (*) mempty = 1 which is not legal and the

Re: [Haskell-cafe] Factoring into type classes

Hi, On Mon, Jan 19, 2009 at 11:06 AM, Jonathan Cast wrote: > On Mon, 2009-01-19 at 10:59 -0800, Iavor Diatchki wrote: >> Hello, >> The multitude of newtypes in the Monoid module are a good indication >> that the Monoid class is not a good fit for the class system > > I would say rather that the c

Re: [Haskell-cafe] Employment

And of course, there's at least half a dozen people on this list at working at Galois. And all documented on the wiki, http://haskell.org/haskellwiki/Haskell_in_industry See you guys at CUFP 09! http://cufp.galois.com/ -- Don pbeadling: > Barclays Capital use it for Equity Derivat

Re: [Haskell-cafe] Employment

Erik de Castro Lopo wrote: > Monad Reader 7 article helped). Fortunately my manager is a really > bright byg, was open to new ideas and already trusted my judgement. Ooops, typo. He's a "really bright guy". Erik -- - Erik de Castr

Re: [Haskell-cafe] Employment

Andrew Coppin wrote: > Is it possible to earn money using Haskell? Does anybody here actually > do this? Its proabably a little harder to find a company that wants a Haskell hacker than it is to find a company where Haskell and other sane languages can be worked in over time. I work for a sma

Re: [Haskell-cafe] Employment

Barclays Capital use it for Equity Derivative modeling and pricing - it's a small team at the moment, but the whole project is in Haskell. I don't work on it myself so I couldn't give you any details (plus I would get fired for blabbing!), I work in an adjacent group. Haskell certainly lends itse

Re: [Haskell-cafe] Haskell WikiProject

-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 On Mon, Jan 19, 2009 at 1:46 PM, Robin Green wrote: > Is anyone else interested in forming a Haskell WikiProject on Wikipedia, > to collaborate on improving and maintaining the coverage and quality of > articles on Haskell-related software and topic

Re: [Haskell-cafe] Employment

On Mon, Jan 19, 2009 at 11:34 AM, Andrew Coppin wrote: > Is it possible to earn money using Haskell? Does anybody here actually do > this? > > Inquiring minds want to know... ;-) > I'm using it at work in simulations... not shipping anything with it yet, but we do ship Erlang :-) Haskell may wo

Re: [Haskell-cafe] Re: Improved documentation for Bool

On Mon, 2009-01-19 at 19:33 +, Andrew Coppin wrote: > rocon...@theorem.ca wrote: > > I noticed the Bool datatype isn't well documented. Since Bool is not > > a common English word, I figured it could use some haddock to help > > clarify it for newcomers. > > My only problem with it is that

Re: [Haskell-cafe] Employment

http://www.haskell.org/haskellwiki/Haskell_in_industry could be of interest to you On Mon, Jan 19, 2009 at 2:34 PM, Andrew Coppin wrote: > Is it possible to earn money using Haskell? Does anybody here actually do > this? > > Inquiring minds want to know... ;-) > >

[Haskell-cafe] Employment

Is it possible to earn money using Haskell? Does anybody here actually do this? Inquiring minds want to know... ;-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] Re: Improved documentation for Bool

rocon...@theorem.ca wrote: I noticed the Bool datatype isn't well documented. Since Bool is not a common English word, I figured it could use some haddock to help clarify it for newcomers. My only problem with it is that it's called Bool, while every other programming language on Earth calls

Re: [Haskell-cafe] Expect module?

Donn Cave wrote: > Quoth Neil Mitchell : > > >> Is there a Haskell-Expect module? Something that would allow me to > >> control an external Unix program via its stdin/stdout/stderr? > > > > System.Process does what you want, I think: > > It might not. Expect uses pseudottys (cf. openpty()), and

Re: [Haskell-cafe] Open unqualified imports

On Fri, Jan 16, 2009 at 06:42:46AM -0800, eyal.lo...@gmail.com wrote: > > Closed-unqualified import: > import Data.Map(Map, lookup) One problem with this style is that you can get lots of conflicts from your VCS if you have multiple people working on the same module. Thanks Ian ___

Re: [Haskell-cafe] Factoring into type classes

On Mon, 2009-01-19 at 10:59 -0800, Iavor Diatchki wrote: > Hello, > The multitude of newtypes in the Monoid module are a good indication > that the Monoid class is not a good fit for the class system I would say rather that the class system is not a good fit for Monoid. Proposals for local instanc

Re: [Haskell-cafe] Haskell WikiProject

* Robin Green [2009-01-19 18:46:43+] > Here's a good example to start with. The article on Eager evaluation > could do with some improvement - and possibly should be merged into the > Lazy evaluation article, I'm not sure: > > http://en.wikipedia.org/wiki/Eager_evaluation I was also disappoi

[Haskell-cafe] Re: some ideas for Haskell', from Python

Manlio Perillo wrote: Brandon S. Allbery KF8NH ha scritto: > ...in theory. In practice GHC needs help with circular imports, and some cycles might be impossible to resolve. This is interesting. Where can I find some examples? Is this explained in the Real World Haskell book? I have no i

Re: [Haskell-cafe] Factoring into type classes

Hello, The multitude of newtypes in the Monoid module are a good indication that the Monoid class is not a good fit for the class system (it is ironic that discussing it resulted in such a huge thread recently :-). How I'd approach the situation that you describe would depend on the context (did

Re: [Haskell-cafe] Haskell WikiProject

greenrd: > Is anyone else interested in forming a Haskell WikiProject on Wikipedia, > to collaborate on improving and maintaining the coverage and quality of > articles on Haskell-related software and topics (broadly defined)? Not > just programming topics specific to Haskell, but also ones of inte

Re: [Haskell-cafe] How to make code least strict?

On Mon, 19 Jan 2009 17:36:30 + "Thomas DuBuisson" wrote: > On Mon, Jan 19, 2009 at 4:48 PM, Robin Green > wrote: > > What guidelines should one follow to make Haskell code least-strict? > > There was a great Cafe discussion started by Henning on just this. He > provided this link: > > htt

[Haskell-cafe] Haskell WikiProject

Is anyone else interested in forming a Haskell WikiProject on Wikipedia, to collaborate on improving and maintaining the coverage and quality of articles on Haskell-related software and topics (broadly defined)? Not just programming topics specific to Haskell, but also ones of interest to the Haske

Re: [Haskell-cafe] Expect module?

On 2009 Jan 19, at 3:47, Neil Mitchell wrote: Is there a Haskell-Expect module? Something that would allow me to control an external Unix program via its stdin/stdout/stderr? System.Process does what you want, I think: http://hackage.haskell.org/packages/archive/process/1.0.1.1/doc/html/System

Re: [Haskell-cafe] plugins can not be installed in ghc 6.10.1

agocorona: >Do really pluigins needs Cabal (>=1.4 && <1.5) ??? >C:\Documents and Settings\Administrator>cabal install plugins >Resolving dependencies... >cabal: dependencies conflict: ghc-6.10.1 requires Cabal ==1.6.0.1 however >Cabal-1.6.0.1 was excluded because plugins-1.3.1 r

[Haskell-cafe] Re: ANN: hledger 0.3 released

The cabal file still includes the vty dependency, but simply removing it made it compile. -- From: "Simon Michael" Sent: Sunday, January 18, 2009 7:04 PM To: "Sebastian Sylvan" Cc: ; Subject: Re: ANN: hledger 0.3 released I've pushed a patch wh

Re: [Haskell-cafe] Expect module?

Quoth Neil Mitchell : >> Is there a Haskell-Expect module? Something that would allow me to >> control an external Unix program via its stdin/stdout/stderr? > > System.Process does what you want, I think: It might not. Expect uses pseudottys (cf. openpty()), and select(). System.Process support

Re: [Haskell-cafe] Factoring into type classes

> As a side curiosity, I would love to see an example of any data structure > which has more than one Functor instance. Especially those which have > more than one useful functor instance. data Record a b = R { field1 :: a, field2 :: b } If I want to use fmap to transform either field, I have to

Re: [Haskell-cafe] How to make code least strict?

On Mon, Jan 19, 2009 at 4:48 PM, Robin Green wrote: > What guidelines should one follow to make Haskell code least-strict? There was a great Cafe discussion started by Henning on just this. He provided this link: http://www.haskell.org/haskellwiki/Maintaining_laziness __

Re: [Haskell-cafe] plugins can not be installed in ghc 6.10.1

-BEGIN PGP SIGNED MESSAGE- Hash: SHA512 2009/1/19 Alberto G. Corona : -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.9 (GNU/Linux) iEYEAREKAAYFAkl0uKYACgkQvpDo5Pfl1oJ30wCfQzX80TulZxyyLLyaAcU/LPVc PPMAoJl8tjhfrlWwoQ9yVGXlXStMDs+O =lf6T -END PGP SIGNATURE- > > Do really pluigins

[Haskell-cafe] plugins can not be installed in ghc 6.10.1

Do really pluigins needs Cabal (>=1.4 && <1.5) ??? C:\Documents and Settings\Administrator>cabal install plugins Resolving dependencies... cabal: dependencies conflict: ghc-6.10.1 requires Cabal ==1.6.0.1 however Cabal-1.6.0.1 was excluded because plugins-1.3.1 requires Cabal ==1.4.* _

Re: [Haskell-cafe] runghc Setup.hs doitall

C:\Documents and Settings\Administrator>cabal install plugins Resolving dependencies... cabal: dependencies conflict: ghc-6.10.1 requires Cabal ==1.6.0.1 however Cabal-1.6.0.1 was excluded because plugins-1.3.1 requires Cabal ==1.4.* 2009/1/19 Alberto G. Corona > > > I finally installed cabal-in

[Haskell-cafe] Re: How to make code least strict?

Robin Green wrote: What guidelines should one follow to make Haskell code least-strict? Obviously the use of "seq" and bang-patterns make code more strict. Code is strict when it evaluates values to determine a pattern match. So avoiding that makes code lazier. Values are evaluated when dec

[Haskell-cafe] How to make code least strict?

What guidelines should one follow to make Haskell code least-strict? -- Robin ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Factoring into type classes

The desugaring of (, a) would involve some type level lambda, and that's not something that is available (yet). -- Lennart On Mon, Jan 19, 2009 at 1:49 PM, Holger Siegel wrote: > Am Montag, den 19.01.2009, 14:47 +0100 schrieb Daniel Fischer: >> Am Montag, 19. Januar 2009 14:31 schrieb Antoine

[Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool

Nicolas Pouillard wrote: Excerpts from Matti Niemenmaa's message of Sun Jan 18 19:47:46 +0100 2009: 3. Coadjute keeps track of command line arguments (see docs for details): for me this is really a killer feature, I don't know of anything else which does this. ocamlbuild does th

Fwd: [Haskell-cafe] runghc Setup.hs doitall

I finally installed cabal-install in windows.. I had a copy of sh.exe for windows time ago so I could use bootstrap. The only additional thing needed is wget(http://users.ugent.be/~bpuype/wget/). finally I moved the resulting cabal.exe to ghc/bin 2009/1/19 Duncan Coutts On Mon, 2009-01-19 at 01:

Re: [Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool

Excerpts from Matti Niemenmaa's message of Sun Jan 18 19:47:46 +0100 2009: > Henning Thielemann wrote: > > Matti Niemenmaa schrieb: > >> Announcing the release of Coadjute, version 0.0.1! > >> > >> Web site: http://iki.fi/matti.niemenmaa/coadjute/ > >> Hackage: > >> http://hackage.haskell.org/cgi-b

Re: [Haskell-cafe] Factoring into type classes

Am Montag, den 19.01.2009, 14:47 +0100 schrieb Daniel Fischer: > Am Montag, 19. Januar 2009 14:31 schrieb Antoine Latter: > > 2009/1/19 Luke Palmer : > > > As a side curiosity, I would love to see an example of any data structure > > > which has more than one Functor instance. Especially those whi

Re: [Haskell-cafe] Factoring into type classes

Am Montag, 19. Januar 2009 14:31 schrieb Antoine Latter: > 2009/1/19 Luke Palmer : > > As a side curiosity, I would love to see an example of any data structure > > which has more than one Functor instance. Especially those which have > > more than one useful functor instance. > > (,) ? > > -Anto

Re: [Haskell-cafe] Factoring into type classes

2009/1/19 Luke Palmer : > On Mon, Jan 19, 2009 at 3:58 AM, Patai Gergely > wrote: >> >> However, there are other type classes that are too general to assign >> such concrete uses to. For instance, if a data structure can have more >> than one meaningful (and useful) Functor or Monoid instance, > >

Re: [Haskell-cafe] Factoring into type classes

2009/1/19 Luke Palmer : > As a side curiosity, I would love to see an example of any data structure > which has more than one Functor instance. Especially those which have more > than one useful functor instance. (,) ? -Antoine ___ Haskell-Cafe mailin

[Haskell-cafe] Re: Bug in Text.Regex.PCRE - do not accept national symbol in pattern

Alexandr, Thanks for sending me this question about unicode and regex-pcre. I will share with the mailing list. This is an encoding issue. From the haddock documentation for regex-pcre: http://hackage.haskell.org/packages/archive/regex-pcre/0.94.1/doc/html/Text-Regex-PCRE.html "Using the

[Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool

Paul Moore wrote: 2009/1/18 Matti Niemenmaa : Announcing the release of Coadjute, version 0.0.1! [...] Portability is striven towards in two ways: Is it intended to work on Windows? (I don't want to spend time downloading and trying to set it up if it was never intended to be Windows-compat

[Haskell-cafe] Re: Different return type?

John Ky wrote in article in gmane.comp.lang.haskell.cafe: > data Person = Person { name :: String, ... } > data Business = Business { business_number :: Int, ...} > > key person = name person > key business = business_number business Let's make this concrete: data Person = Person { name ::

Re: [Haskell-cafe] Factoring into type classes

On Mon, Jan 19, 2009 at 3:58 AM, Patai Gergely wrote: > However, there are other type classes that are too general to assign > such concrete uses to. For instance, if a data structure can have more > than one meaningful (and useful) Functor or Monoid instance, As a side curiosity, I would love t

Re: [Haskell-cafe] ANNOUNCE: Coadjute 0.0.1, generic build tool

2009/1/18 Matti Niemenmaa : > Announcing the release of Coadjute, version 0.0.1! [...] > Portability is striven towards in two ways: Is it intended to work on Windows? (I don't want to spend time downloading and trying to set it up if it was never intended to be Windows-compatible.) Paul. __

[Haskell-cafe] Re: ANNOUNCE: Coadjute 0.0.1, generic build tool

Brandon S. Allbery KF8NH wrote: On 2009 Jan 18, at 13:47, Matti Niemenmaa wrote: 3. Coadjute keeps track of command line arguments (see docs for details): for me this is really a killer feature, I don't know of anything else which does this. It's been done many times before; it never

Re: [Haskell-cafe] Factoring into type classes

As for multiple Monoid or Functor instances, simply define a newtype, as it is done in Data.Monoid. What part of your question does that answer and what part doesn't it? 2009/1/19 Patai Gergely : > Hi everyone, > > I have a general program design question, but I can't really think of > good exampl

[Haskell-cafe] Factoring into type classes

Hi everyone, I have a general program design question, but I can't really think of good examples so it will be a bit vague. There was a discussion on Show not long ago which brought up the problem that there are several ways to "show" a data structure, and it depends on the context (or should I ca

[Haskell-cafe] Re: Different return type?

"John Ky" writes: > Hi, > > Possibly a silly question but is it possible to have a function that has a > different return type based on it's first argument? Are you sure that's what you really want? > For instance > > data Person = Person { name :: String, ... } > data Business = Business { bus

Re: [Haskell-cafe] Different return type?

Hello! I wouldn't use either. It seems like it complicates things quite a lot and it looks like this could be solved more simply by setting up the data types or organizing functions differently. Is there a specific problem that you're solving or are you just curious about different return types

Re: [Haskell-cafe] Graham-Scan Algorithm exercise from Chapter 3 Real World Haskell

Am Montag, 19. Januar 2009 10:17 schrieb Daniel Fischer: > Am Montag, 19. Januar 2009 09:32 schrieb Michael Litchard: > > I have started the Graham Scan Algorithm exercise. I'm getting tripped > > up by the sortByCotangent* function. > > Here's what I have so far > > > > data Direction = DStraight

[Haskell-cafe] Re: Comments from OCaml Hacker Brian Hurt

david48 wrote: > Apfelmus, Heinrich wrote: > >> Hm, what about the option of opening Bird's "Introduction on Functional >> Programming using Haskell" in the section about fold? Monoid is on page >> 62 in the translated copy I've got here. > >> I don't think that I would try to learn a programming l

Re: [Haskell-cafe] Graham-Scan Algorithm exercise from Chapter 3 Real World Haskell

Am Montag, 19. Januar 2009 09:32 schrieb Michael Litchard: > I have started the Graham Scan Algorithm exercise. I'm getting tripped > up by the sortByCotangent* function. > Here's what I have so far > > data Direction = DStraight > >| DLeft >| DRight > >

[Haskell-cafe] Re: walking a directory tree efficiently

Massimiliano Gubinelli wrote: Hi, what about avoid the use of the unfold over the tree and construct it directly (e.g. see http://hpaste.org/13919#a3)? Nice solution! I wonder if there is (an easy) possibility to construct the tree lazily so that output start immediately for large trees.

Re: [Haskell-cafe] Expect module?

Hi Erik, > Is there a Haskell-Expect module? Something that would allow me to > control an external Unix program via its stdin/stdout/stderr? System.Process does what you want, I think: http://hackage.haskell.org/packages/archive/process/1.0.1.1/doc/html/System-Process.html Thanks Neil ___

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