. We are more than happy to answer informal enquiries. Contact
Duncan Coutts, Ian Lynagh or Andres Löh
(http://www.well-typed.com/who_we_are/) for further information,
either by email or IRC.
The deadline for applications is Friday 27th January 2012.
== About Well-Typed
Well-Typed LLP is a Haskell
programing is required.
Speakers
Ralf Hinze (Oxford University)
Andres Löh (Well-Typed)
Simon Marlow (Microsoft Research)
Talks (to be confirmed)
Joe Armstrong, Mark Shinwell, Anil Madhavapeddy.
Registration and contact:
The deadline for registration is May 30, 2012. Please contact:
Régis Vizet
I'm pleased to announce the long-awaited new release of
cabal-install-0.14.0
If you are already using cabal-install then you can upgrade both using:
$ cabal update
$ cabal install Cabal cabal-install
New users you can get it from:
http://haskell.org/cabal/download.html
For users on
Hi Johan.
I think this is (indirectly) Duncan's fault. He convinced me it'd be a
good idea to add a global Hackage preference cabal-install 0.14
for now, so that not everybody gets an upgrade warning immediately.
But this also means that you have to explicitly select
cabal-install-0.14.0 in
Hi Ryan.
It built fine for me.
Glad to hear that.
I notice that it doesn't have the parallel build patches from the GSOC.
That's right.
I've been using cabal with those patches for a while and was wondering what
this signifies for the future inclusion of them in a release?
They will be
Krishnaswami, Max Planck Institute for Software Systems
Andres Löh (co-chair), Well-Typed LLP
Zoltan Porkolab, Eötvös Loránd University
Chung-chieh Shan, University of Tsukuba
Proceedings and Copyright
-
We plan to have formal proceedings, published by the ACM. Authors
On Sat, May 12, 2012 at 12:45 AM, Janis Voigtländer
j...@informatik.uni-bonn.de wrote:
On behalf of all the contributors, I am pleased to announce that the
Haskell Communities and Activities Report
(22nd edition, May 2012)
Thank you very much, Janis. Great work
Kennedy, Microsoft Research Cambridge
Neelakantan Krishnaswami, Max Planck Institute for Software Systems
Andres Löh (co-chair), Well-Typed LLP
Zoltan Porkolab, Eötvös Loránd University
Chung-chieh Shan, University of Tsukuba
Proceedings and Copyright
-
We plan to have formal
Hi Chris.
The key feature is the way it integrates the multiple tool chains into a
single virtual tool chain with
a sandboxing mechanism provided by the hub hackage.
I think the Nix distribution might be a natural fit for 'hub' integration --
I would be happy
to work with the Nix people on
--
CALL FOR LIGHTNING TALKS / CHALLENGES
--
At the Workshop on Generic Programming 2012 on Sunday, September 9, 2012,
we will have a discussion about
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell mailing list
Haskell@haskell.org
http://www.haskell.org/mailman/listinfo/haskell
data access and manipulation
Neil Mitchell (Standard Chartered)
Everyone should use a Generics library - writing HLint with Uniplate
Adam Bergmark (Silk)
Compiling Haskell to Javascript with Fay
Andres Löh (Well-Typed LLP)
Monads for free!
Gracjan Polak (Scrive)
Embedded domain specific languages
Hi.
There's a new monthly Haskell meeting in Regensburg, Bavaria, Germany.
Tomorrow will be our third meeting, and the first one with a Haskell
talk:
Tuesday, 12 November 2013
20:00
Plan 9, Werftstraße 15, 93059 Regensburg
There'll be a short presentation by Martin Ruderer on how to solve
Hi everyone.
The 5th edition of the Haskell eXchange is going to take place on
October 6 and 7 in London, and we are still looking for contributions
on all aspects of Haskell (and related programming languages).
It does not matter whether you are going to present your own project
or want to
, 1-day on types, 2-day on
performance) offered by Well-Typed on the surrounding days. More info
here: http://www.well-typed.com/blog/125/
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
Registered in England & Wales, OC335890
250 Ice Wharf, 17
Hi.
The definitions are accepted by GHC:
class Functor f where
type FC f a :: Constraint
type FC f a = ()
fmap :: (FC f a, FC f b) = (a - b) - f a - f b
instance Functor [] where
fmap = map
Yes. This is what I would have expected to work.
But I don't like
Hi Burak.
You seem to assume that old strategies use a different GC policy than
new strategies. My understanding is that this is not true. The WEAK
policy is used in general now. So old strategies shouldn't be used
with more recent GHCs, or you'll lose parallelism.
Cheers,
Andres
Hi there.
First of all: I'm aware that the current situation with cabal-install
is suboptimal and a new release it desperately needed.
Still, some general advice and attempts at explaining strange behaviour:
On Wed, Feb 1, 2012 at 8:05 AM, Evan Laforge qdun...@gmail.com wrote:
So it
Hi Conal.
On Sun, Feb 5, 2012 at 12:36 AM, Conal Elliott co...@conal.net wrote:
Since upgrading to 7.4.1, if I 'cabal install' successfully and then 'cabal
install' a second time without first doing a 'ghc-pkg unregister
package-name', I get the following complaint:
[...]
The warning is
In addition, I'm planning to make the warning a little bit less
aggressive before the release.
Before the release of what? (seeing as GHC 7.4.1 has been released)
Sorry, I should have been clear. Before the release of cabal-install.
The described behaviour only occurs in the current
Hi Conal.
Thanks for the reply! Note that I get this message even running 'cabal
install' a second time after changing nothing. Is that scenario an example
of what you mean by a potentially dangerous cabal invocation?
The check currently is entirely ad-hoc. Any reinstallation of an
existing
I've been
unable to avoid this error message by any other means that (a) 'ghc-pkg
unregister package' or (b) '--force-reinstall'. So far, '--solver=modular'
hasn't helped. So I'm hoping for something less aggressive. In particular,
in case nothing has changed, I want 'cabal install' to
Hi Thijs.
Sorry if this has been discussed before.
In my opinion, the main advantage of Agda goals is not that the type
of the hole itself is shown, but that you get information about all
the locally defined identifiers and their types in the context of the
hole. Your page doesn't seem to
Hi Brent.
as others have indicated, it can relatively easily be simulated
already.
I don't think this is true. The wiki page includes a discussion of
the current methods for simulating holes and their (substantial)
disadvantages. In order to be useful it seems to me that it must be
Hi.
Here's a way that seems to work for me. I haven't tested in detail.
There may be problems, or also easier ways to achieve the same. The
DataKinds extension isn't essential. I've just used it for fun.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well
need the type family declarations.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Glasgow-haskell-users mailing list
Glasgow-haskell-users@haskell.org
http://www.haskell.org/mailman/listinfo/glasgow
Hi Bas.
I'm hitting on an issue when deriving Generic for an associated data type:
[...]
Your example compiles for me with HEAD (but fails with 7.4.1 and
7.4.2, yes). I've not tested if it also works.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well
Hi.
This one looks strange to me:
-- Stripping a type from all its arguments
type family Strip (t :: *) :: k
I'd be tempted to read this as saying that
Strip :: forall k. * - k
So the result of Strip would actually have to be kind-polymorphic. I'm
surprised that
type instance Strip
Hi.
I had said earlier that:
This one looks strange to me:
-- Stripping a type from all its arguments
type family Strip (t :: *) :: k
I'd be tempted to read this as saying that
Strip :: forall k. * - k
So the result of Strip would actually have to be kind-polymorphic. I'm
surprised
?
Thanks.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
Registered in England Wales, OC335890
250 Ice Wharf, 17 New Wharf Road, London N1 9RF, England
___
Glasgow-haskell-users mailing list
Glasgow
Hi.
I do not know why, my ghc 7.2.1 does not seem to support
DeriveRepresentable. I compiled the ghc 7.2.1 myself by ghc 7.0.4. All
options default.
$ ghc Types/TopTalkerRecord.hs
Types/TopTalkerRecord.hs:2:14:
Unsupported extension: DeriveRepresentable
There's no extension of that
Hi there.
I tried to follow the program of the paper Scrap your boilerpolate
Revolutions. Unfortunately,
I found the program in the section lifted spine view does not compile in my
GHC, could anybody
point out where I am wrong? Many Thanks
My code is posted here http://hpaste.org/54357
. We are more than happy to answer informal enquiries. Contact
Duncan Coutts, Ian Lynagh or Andres Löh
(http://www.well-typed.com/who_we_are/) for further information,
either by email or IRC.
The deadline for applications is Friday 27th January 2012.
== About Well-Typed
Well-Typed LLP is a Haskell
Hi.
On Fri, Feb 3, 2012 at 7:44 AM, Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com wrote:
On 3 February 2012 17:29, Magicloud Magiclouds
magicloud.magiclo...@gmail.com wrote:
Thank you. The document does say it more clearly than me.
But still, currently, ghc only gives me one option: cannot
I am just wanting an option (ignore versions) to take that risk in
develop environment.
A controlled way of ignoring version constraints (mainly upper bounds,
actually) is certainly on my TODO list for the new solver. The main
issue to work out is a good way how to control the disabled bounds
Hi.
--force-allow=foo-1.3
with the semantics that all dependencies on foo will be changed to
allow foo-1.3 to be chosen. Would that be ok? Other suggestions?
Can't this be integrated with the current --constraint flag?
It could be, but ...
If the
constraint is able to be satisfied
I don't understand what's going on here. Instances for V1 should of
course be defined if they can be! And in this case, a V1 instance
makes sense and should be defined. The definition itself doesn't
matter, as it'll never be executed.
Cheers,
Andres
Hi.
I don't understand what's going on here. Instances for V1 should of
course be defined if they can be! And in this case, a V1 instance
makes sense and should be defined. The definition itself doesn't
matter, as it'll never be executed.
The definition certainly matters:
[...]
You're
Would you have an example of a type for which it would be useful to have
a DeepSeq instance, and that would require a V1 instance? I cannot think
of one now; I originaly thought it would be necessary to permit deriving
DeepSeq instances for types tagged with void types, but as José
explained,
Hi.
$ cabal install persistent
Resolving dependencies...
In order, the following would be installed:
aeson-0.6.0.2 (reinstall) changes: mtl-2.1.1 - 2.0.1.0
persistent-0.9.0.3 (new package)
cabal: The following packages are likely to be broken by the reinstalls:
buildwrapper-0.5.2
Use
to generate
accessor functions. These aren't covered by your tests. Therefore the
datatype shows as not completely covered.
HTH,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe
c1 c2 a
typeOfInnerProxy :: ProxyWrapper (Ext Typeable constraint) - TypeRep
typeOfInnerProxy (ProxyWrapper p) = typeOfArg p
This will certainly require all sorts of undecidable instances :) But
does it work for you?
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http
)' and it would
work.
then the following would give a type error:
oops :: TypeRep
oops = typeOfInnerProxy p
Yes, and correctly so. Because Typeable isn't even a superclass of
Num. So there's no way to know that p actually contains a Typeable
proxy.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Hi Chris.
[Sorry if I'm slow responding, but I'm at a summer school right now
and have relatively little time to follow my email.]
At issue is whether the JustHub Haskell distribution for Enterprise Linux
and
the hub hackage for sandboxing development projects and integrating multiple
GHC
Hi.
Hackage A depends on magicloud (any) and container (0.4.0.0), and
hackage magicloud depends on container (any).
Now I've installed magicloud, using container 0.5.0.0. Then I failed
to install A, with any solver.
So the solvers are using the status that is installed, not the
definitions
,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
that it lists only some of the
dependencies. It's a general phenomenon. I don't understand the way
Hackage lists package dependencies. I'd appreciate if it'd actually
show the whole conditional tree of dependencies.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well
type signature.)
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
idea in general. There are simply too many
cases where installing older versions of packages (which is often the
only thing that helps) is not really the solution you want. That's
also the reason why it's not enabled by default.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP
better than using --avoid-reinstalls by default. However, it
may still send the misleading message that a package builds just
fine when it practice it doesn't.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
, but this will kill any
performance, if needed.
There's
http://hackage.haskell.org/package/safeint/
It's not implemented quite as efficiently as it theoretically could
be, but it might do more or less what you want.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well
,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
, but it's currently
listed as not active on
http://www.haskell.org/haskellwiki/User_groups. Perhaps there's a
chance to bring it back to life?
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe
Do you have any suggestions to install xmobar in this particular case?
In case of executables I usually rm -rf ~/.ghc, cabal install,
and rm -rf ~/.ghc again. Executables are still here (in ~/.cabal/bin),
but all libraries are lost. Warning: it may break your development
environment, so make
Hi Iavor.
If you don't want to use the class system, you could write `repeat` with a
type like this:
repeat :: Proxy n - a - Vector n a
(`Proxy` is the singleton family 'data Proxy n = Proxy`).
How is the polymorphism becoming any less parametric by using this
particular Proxy type?
Hi Kazu.
I'm now studying Trie in Okasaki's Purely Functional Data Structure.
Attached is the program in its appendix. I cannot understand how to
use empty, look and bind. For instance, if I type 'look empty',
I got an error:
look empty
interactive:2:1:
No instance for (FiniteMap m0
Hi Johan.
I haven't looked in detail at the overall problem, but:
Flags chosen: base3=True, base4=True
Why is Cabal setting both base3 and base4 to True?
This looks completely fine to me.
The Cabal .cabal file is stating:
if flag(base4) { build-depends: base = 4 } else { build-depends:
x = K1 val
rewrite _ _ = K1 NIL
Does this help you?
(I'm attaching the full code.)
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
GRewrite.hs
Description: Binary data
___
Haskell-Cafe mailing list
to use.
(It's entirely possible that my code can be simplified further. I
haven't thought about this for very long ...)
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe
Hi Kazu.
I'd be surprised if zipWith' yields significant improvements. In the
case of foldl', the strictness affects an internal value (the
accumulator). However, in the case of zipWith', you're just forcing
the result a bit more, but I guess the normal use pattern of fibs is
that you want to see
Well, it took a little bit of persuasion to let GHC not cache the list(s), but
with
fibs :: Int - Integer
fibs k = igo i !! k
where
i | k 100 = 1
| otherwise = 2
igo :: Integer - [Integer]
igo i = let go = 0 : i : zipWith (+) go (tail go) in go
etc.,
Hi John.
What are the prospects for Haskell supporting Structured Graphs as defined
here?
http://www.cs.utexas.edu/~wcook/Drafts/2012/graphs.pdf
Is there an interest by developers of GHC in doing this?
Could you be more specific about the kind of support you'd expect
from GHC? Basically all
Hi.
while playing with folds and trying to implement `!!` by folding, I came to
the conclusion that:
- `foldr` is unsuitable because it counts the elements from the end, while
`!!` needs counting from the start (and it's not tail recursive).
What is the problem with the following definition
indeed does not enable rank-n types, but only allows you to use
the forall syntax.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org
that implement such functionality, though.
By using deepseq-generics, you can import Control.DeepSeq.Generics and
then define
instance NFData Simple where rnf = genericRnf
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
ghc is installed globally, and local packages should not break it.
still cabal-install says so (and I don't dare to test ...)
If you're installing locally or (even better) in a sandbox, then you
cannot completely (i.e., irrevocably) break your compiler. You can
always remove the package db.
in the current Haskell Platform.
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://www.haskell.org/mailman/listinfo/haskell-cafe
easier
to understand.
(And yes, I would be willing to be mentor for this project.)
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
___
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http
rmWatch nd1 wd3
-- These lines cause type errors:
-- rmWatch nd1 wd0
-- rmWatch nd0 wd3
printInotifyDesc nd0
printInotifyDesc nd1
Cheers,
Andres
--
Andres Löh, Haskell Consultant
Well-Typed LLP, http://www.well-typed.com
Hi.
I'd like to nominate myself for membership in the new Haskell Prime committee.
About me:
* I've been a Haskell user since 1997.
* Back then, to learn Haskell, I read the entire Haskell 1.4 language report.
* I have experience in programming languages theory and language
design, with most of
Hi.
It was my understanding that Herbert would be the chair when I asked
to be on the committee, and the fact that this question was already
answer was a factor in my decision to try to help. Being the committee
chair is less a position of power, and more a position of
responsibility. I think we
71 matches
Mail list logo
