Hi,
Please use GHC 7.6 for experimenting with PolyKinds/DataKinds; the
implementation in 7.4 was not fully complete. Your code compiles fine in
7.6.
Cheers,
Pedro
On Fri, Oct 26, 2012 at 3:10 AM, Ahn, Ki Yung wrote:
> Promotion works for user defined lists such as
>
> data List a = Nil | Cons
On Thu, Oct 25, 2012 at 06:34:53PM -0400, Jake McArthur wrote:
> I golfed a bit. :)
>
> sequence <=< filterM (const [False ..])
I was thinking of golfing this myself tonight, but probably
wouldn't have come up with this. Thanks for sparing me the effort.
Bravo!
Alex
___
Promotion works for user defined lists such as
data List a = Nil | Cons a (List a)
And, if I use (List Bool) instead of [Bool] everything works out.
It's only the Haskell list type constructor [] is being a problem.
In the "Giving Haskell a promotion" paper, it says that Haskell lists
are "nat
I would love to see an awesome online learning experience for
Haskell too.
We really need to make it easier for people to learn Haskell.
Thank you for pointing this out to the community.
On 10/18/2012 2:19 PM, niket wrote:
I am a novice in Haskell
Most part of Conor's talk at ICFP, until just before the last stage
where he heavily uses true value dependency for compiler correctness all
the code seemed to be able to translate into Haskell with the new hot
DataKinds and PolyKinds extension.
I tried it in GHC 7.4.1 and it was possible to d
I golfed a bit. :)
sequence <=< filterM (const [False ..])
On Thu, Oct 25, 2012 at 6:11 PM, dokondr wrote:
>
> On Fri, Oct 26, 2012 Alex Stangl wrote:
>
>>
>> combos [] = [[]]
>> combos ([]:ls) = combos ls
>> combos ((h:t):ls) = map (h:) (combos ls) ++ combos (t:ls)
>>
>
> Excellent, thanks!
On Fri, Oct 26, 2012 Alex Stangl wrote:
>* *
> combos [] = [[]]
> combos ([]:ls) = combos ls
> combos ((h:t):ls) = map (h:) (combos ls) ++ combos (t:ls)
>
Excellent, thanks!
___
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Haskell-Cafe@haskell.org
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On Fri, Oct 26, 2012 at 12:44:31AM +0400, dokondr wrote:
> I am looking for the algorithm and code better then the one I wrote (please
> Build all possible element combinations from N lists.
> Valid combination consists of k <= N elements.
> Where each element of a single combination is taken from
On Thu, Oct 25, 2012 at 4:57 PM, Gregg Lebovitz wrote:
> I am trying to get a learning center started in the Haskell community. As
> pointed out below, MOOCs are hard to put together, however training and
> videos straight forward. There is a lot of teaching material available in
> the community.
I am trying to get a learning center started in the Haskell
community. As pointed out below, MOOCs are hard to put together,
however training and videos straight forward. There is a lot of
teaching material available in the community. It is a matter of
finding, organizing
Hi all,
I am looking for the algorithm and code better then the one I wrote (please
see below) to solve the problem given in the subject.
Unfortunately I finally need to implement this algorithm in Java. That's
why I am not only interested in beautiful Haskell algorithms, but also in
the one that I
Hi,
Haskell compilers optimize tail recursive functions as cycles, which
improves both memory and CPU complexity. However, it's easy to make a
mistake and break the conditions under which a function can be tail
recursive and thus optimized. Is there a way to tell a Haskell
compiler that a functi
Hi Paul,
On Thu, Oct 25, 2012 at 4:22 PM, Paul Visschers wrote:
> Hello everyone,
>
> I've been playing around with the data kinds extension to implement
> vectors that have a known length at compile time. Some simple code to
> illustrate:
> > {-# LANGUAGE DataKinds, GADTs, KindSignatures #-}
> >
Hello,
Sorry, I made a mistake, the version of 'repeat :: Proxy n -> a -> Vector n
a' won't work either, as Andres noticed, because `Proxy` still won't give
you information about how many times to repeat.
You'd have to use a structured singleton family, where the values are
linked to the types:
d
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 t
Hello Paul,
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`).
You can't really do it with a function of type `a -> Vector n a` because
there is no way for
Hello everyone,
I've been playing around with the data kinds extension to implement vectors
that have a known length at compile time. Some simple code to illustrate:
> {-# LANGUAGE DataKinds, GADTs, KindSignatures #-}
>
> import Prelude hiding (repeat)
>
> data Nat = Zero | Succ Nat
> data Vector
The closest available is:
http://www.youtube.com/playlist?list=PL386777DEA831CB75&feature=playlist-comment
http://www.inf.ed.ac.uk/teaching/courses/inf1/fp/
Thanks,
Niket
On Thu, Oct 25, 2012 at 2:07 AM, David McBride wrote:
> I'm taking it primarily because it is taught by the guy who made t
There is also the Haskell course (21 videos) given by Philip Wadler (one or
the creators of Haskell) at University of Edinburgh in 2011. The first
video is available at
http://www.youtube.com/watch?v=AOl2y5uW0mA&feature=relmfu .
Course materials (lecture notes, exercises, solutions, references, et
On Thu, Oct 25, 2012 at 12:10 PM, Jesse Schalken wrote:
> What if you ran the program from within the directory that contains
> git.exe?
That seems to work.
> Can you check that the PATH environment variable is set correctly from
> within the program?
>
If I run `system "echo %PATH%"` it sho
What if you ran the program from within the directory that contains
git.exe? Can you check that the PATH environment variable is set correctly
from within the program?
On Thu, Oct 25, 2012 at 10:05 PM, José Pedro Magalhães wrote:
> Hi all,
>
> Consider the following program:
>
> module Test wher
Hi all,
Consider the following program:
module Test where
>
> import System.Process (readProcess)
>
> main :: IO ()
> main = readProcess "git" ["describe", "--tags"] "" >>= putStr
>
In Windows I get the following behaviour:
> git --version
> git version 1.7.10.msysgit.1
>
> > ghc --version
> Th
Hi,
I designed my event engine like this:
-- | events types
data Player = Arrive | Leave deriving (Typeable, Show, Eq)
data RuleEvent = Proposed | Activated | Rejected | Added | Modified |
Deleted deriving (Typeable, Show, Eq)
data Time deriving Typeable
data InputChoice c deriving Type
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