The following message was sent to me, but was apparently intended for
this thread, so I am forwarding it to the Haskell-Cafe Mailing List:
On Mon, Aug. 2, 2010 at 11:44 PM, Gordon Sommers
wrote:
> This looks pretty neat! The website would benefit from one or two
> "full-size" examples I think.
On Mon, Aug 2, 2010 at 4:12 PM, Phyx wrote:
>> I've tried to use leksah but some minor annoying things make it unusable for
>> me.
> I'm curious, what are those minor annoying things?
Trying code completion in comments on string constants, for example.
Code completion makes the text jump if you
At 8:29 PM -0400 8/2/10, Brandon S Allbery KF8NH wrote:
On 8/2/10 19:59 , aditya siram wrote:
Agreed. In fact I have the most trouble imagining what Haskell code looked
like before monads.
IIRC the type of main was something like [Request] -> [Response].
Actually, the Haskell 1.2 report (
=
Call for Participation
The 15th ACM SIGPLAN International Conference
on Functional Programming (ICFP 2010)
http://www.icfpconference.org/icfp2010/
Brandon,
>> Sorry, I was thinking out loud there. I meant the Eval constraint, not the
>> equality constraint. But, right now, I guess my comment only makes sense to
>> me, so let's pretend I kept quiet. ;-)
> The point of this discussion is that the Eval constraint needs to be on one
> of the
On 3 August 2010 15:02, rustom wrote:
> I tried to install pivotal
> According to the site I must do:
> ghc --make Main -fglasgow-exts -package plugins
>
> I get
> cant satisfy package plugins
Which version of GHC are you using? If you're using 6.12, then you're
out of luck: plugins won't work
I tried to install pivotal
According to the site I must do:
ghc --make Main -fglasgow-exts -package plugins
I get
cant satisfy package plugins
I believe the more general problem is that one has to choose between
'direct' cabal installs and using debian's packages. At least this is
the same situ
I am pleased to announce the release of the package "approximate-equality",
which provides newtype wrappers that allow one to effectively override the
equality operator of a value so that it is /approximate/ rather than /exact/.
The wrappers use type annotations to specify the tolerance; the
On Thu, Jul 29, 2010 at 8:47 PM, Ivan Miljenovic
wrote:
> On 30 July 2010 13:32, Peter Schmitz wrote:
> > I have a question about finding the Gtk2Hs demos (the demos written in
> > Haskell).
>
> They're not there:
> http://osdir.com/ml/haskell-cafe@haskell.org/2010-07/msg00724.html
>
Ivan:
Beca
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On 8/2/10 19:59 , aditya siram wrote:
> Agreed. In fact I have the most trouble imagining what Haskell code looked
> like before monads.
IIRC the type of main was something like [Request] -> [Response].
- --
brandon s. allbery [linux,solaris,fre
Agreed. In fact I have the most trouble imagining what Haskell code looked
like before monads.
-deech
On Mon, Aug 2, 2010 at 6:34 PM, Richard O'Keefe wrote:
> The thing that I found hardest to understand about monads is that
> they are used to obtain very special consequences (fitting things
>
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On 8/2/10 17:18 , Stefan Holdermans wrote:
> Brandon,
>>> h :: (x ~ y, Eval (y -> Int)) => (x -> Int) -> (y -> Int) -> Int
>
>> But actually if you push the constraint inward, into the type so to say,
>> you actually get quite close to Janis' and Da
The thing that I found hardest to understand about monads is that
they are used to obtain very special consequences (fitting things
like I/O and updatable arrays into a functional language) without
actually involving any special machinery. Whenever you look for
the magic, it's nowhere. But it's h
On Mon, Aug 2, 2010 at 7:37 PM, Ryan Ingram wrote:
> there's no y.z that fulfills that requirement. Lets rewrite in a
> System-F-style language with data types:
[...]
> So clearly x0 has type (C (A -> r) r)
> However, our input is parametric in r, which is mentioned in x0's
> type, so we need to
there's no y.z that fulfills that requirement. Lets rewrite in a
System-F-style language with data types:
Given
read (/\) as forall, \\ as "big lambda", and @ as "type-level
application" which eliminates big-lambda.
data Category (~>) = CategoryDict
{ id :: (/\a. a ~> a)
, (.) :: (/\a b
Brandon,
>> h :: (x ~ y, Eval (y -> Int)) => (x -> Int) -> (y -> Int) -> Int
> But actually if you push the constraint inward, into the type so to say, you
> actually get quite close to Janis' and David's solution.
Sorry, I was thinking out loud there. I meant the Eval constraint, not the
equ
Brandon,
> Hm. Seems to me that (with TypeFamilies and FlexibleContexts)
>
>> h :: (x ~ y, Eval (y -> Int)) => (x -> Int) -> (y -> Int) -> Int
>
> should do that, but ghci is telling me it isn't (substituting Eq for Eval
> for the nonce):
>
> Prelude> let h :: (x ~ y, Eq (y -> Int)) => (x ->
David Leimbach schrieb:
> Haskell's great and all but it does have a few warts when it comes to
> how much real trust one should put into the type system.
>
> Some compromises still exist like unsafePerformIO that you can't detect
> simply by looking at the types of functions.
>
> In order to li
Dear café,
Given:
instance Category C
y :: forall r. C r (A -> r)
I am looking for the types of x and z such that:
x . y :: forall r. C r r
y . z :: forall r. C r r
Can you help me find such types? I suspect only one of them exists.
Less importantly, at least to me at this moment: how do I
This is a forward of a message from March 4th.
-- Forwarded message --
From: Derek Elkins
Date: Thu, Mar 4, 2010 at 9:43 PM
Subject: Re: Bug in Parsec.Token
To: Don Stewart
Cc: Greg Fitzgerald , Antoine Latter
, "Sittampalam, Ganesh"
, Ian Lynagh ,
librar...@haskell.org
I'm no
On Mon, Aug 2, 2010 at 4:32 AM, Antoine Latter wrote:
> On Mon, Aug 2, 2010 at 1:55 AM, Ivan Miljenovic
> wrote:
> > On 2 August 2010 16:24, Jean-Philippe Bernardy
> wrote:
> >> Can you explain why you could not use the parsec name,
> >> with revision number (say) 2.2?
> >>
> >> This would help
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On 8/2/10 11:41 , Janis Voigtländer wrote:
> alright that we don't know more about where (==) is used. But for a
> function of type f :: Eval (a -> Int) => (a -> Int) -> (a -> Int) ->
> Int, in connection with trying to find out whether uses of seq are
On Mon, Aug 2, 2010 at 5:48 AM, Yitzchak Gale wrote:
> Jason Dagit wrote:
> > There you go for a starter tutorial.
>
> Thanks Jason, that's a great start. It already goes a long way
> towards making Takusen more accessible.
>
> I noticed that QuickCheck is still a dependency. That's
> not a good
Hi,
I am late to reply in this thread, but as I see Stefan has already made
what (also from my view) are the main points:
- Putting seq in a type class makes type signatures more verbose, which
one may consider okay or not. In the past (and, as it seems, again in
every iteration of the language
On Jul 31, 2010, at 6:07 AM, Rustom Mody wrote:
> Do most people who work with haskell use emacs/vi/eclipse or something
> else??
I work on Mac OS X.
On one machine I have Haskell Platform installed. On the other I have ghc,
cabal-install, and various packages installed by hand.
To edit, I us
I use kate as well, mostly out of habit. The autoindenter drives me
crazy though.
On Mon, Aug 2, 2010 at 1:10 PM, David Virebayre
wrote:
> On Sat, Jul 31, 2010 at 12:07 PM, Rustom Mody wrote:
>> Do most people who work with haskell use emacs/vi/eclipse or something
>> else??
>
> I mostly use kat
It's available in MissingH:
http://hackage.haskell.org/packages/archive/MissingH/latest/doc/html/Data-Either-Utils.html#v:maybeToEither
You can find this using Hayoo, which indexes Hackage.
MissingH is pretty huge, though, just for one function. It's kind of
annoying. I'm using this function in
Hi,
Am Montag, den 02.08.2010, 06:34 -0500 schrieb Antoine Latter:
> On Mon, Aug 2, 2010 at 6:32 AM, Antoine Latter wrote:
> > On Mon, Aug 2, 2010 at 1:55 AM, Ivan Miljenovic
> > wrote:
> >>
> >> That said, if parsec2 is only a bug-fix branch of parsec-2.x, is there
> >> any particular reason wo
I find it convenient sometimes to convert a Maybe value to an Either thus
(excuse the syntax, it's CAL, not Haskell):
maybeToEither :: a -> Maybe b -> Either a b;
maybeToEither errorValue = maybe (Left errorValue) (\x -> Right x);
but that seemingly obvious function isn't in Hoogle, AFAICT, so p
I'm curious, what are those minor annoying things?
-Original Message-
From: haskell-cafe-boun...@haskell.org
[mailto:haskell-cafe-boun...@haskell.org] On Behalf Of David Virebayre
Sent: Monday, August 02, 2010 13:11
To: Rustom Mody
Cc: haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe]
Hi all,
I've put together a quick, 9-question State of Haskell, 2010 survey:
http://blog.johantibell.com/2010/08/state-of-haskell-2010-survey.html
The survey will hopefully give us some insight into how people use Haskell
and perhaps also some ideas on how Haskell tools and libraries could b
Jason Dagit wrote:
> There you go for a starter tutorial.
Thanks Jason, that's a great start. It already goes a long way
towards making Takusen more accessible.
I noticed that QuickCheck is still a dependency. That's
not a good idea. It creates a lot of dependency problems,
and most of the time t
Alistair Bayley wrote:
>> We've put some effort into supporting older versions of ghc...
>> Are there any distros still shipping with ghc-6.6?
There are so many distros out there that it is hard to say no. But
Debian, which tends to be very conservative, has not had
a supported version with GHC 6.
On Mon, Aug 2, 2010 at 6:32 AM, Antoine Latter wrote:
> On Mon, Aug 2, 2010 at 1:55 AM, Ivan Miljenovic
> wrote:
>>
>> That said, if parsec2 is only a bug-fix branch of parsec-2.x, is there
>> any particular reason work couldn't be done to improve the performance
>> of parsec-3 when using the co
On Mon, Aug 2, 2010 at 1:55 AM, Ivan Miljenovic
wrote:
> On 2 August 2010 16:24, Jean-Philippe Bernardy wrote:
>> Can you explain why you could not use the parsec name,
>> with revision number (say) 2.2?
>>
>> This would help improve hackage/cabal/... versioning mechanism.
>
> I think the idea is
On Sat, Jul 31, 2010 at 12:07 PM, Rustom Mody wrote:
> Do most people who work with haskell use emacs/vi/eclipse or something
> else??
I mostly use kate, with a separate terminal window running ghci.
I've tried to use leksah but some minor annoying things make it
unusable for me.
David.
___
Nicolas, Luke,
SH> More importantly, the type-class approach is flawed [...]. It assumes
SH> that all seq-related constraints can be "read off from type variables",
SH> which is in fact not the case.
LP> Could you provide an example (or a specific example or explanation in
LP> the paper) of what
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