Hi,
thanks for your interesting ideas an inspiring answers.
However I meant something a bit different. My point wasn't how to
implement this problem with the current set of tools. Instead, I was
wondering if it'd be worth expanding the current Reader/Writer
library.
Best regards,
Petr
201
Daniel van den Eijkel gmx.net> writes:
> ... but I use HDBC and I'm happy with it.
including its handling of character encodings?
(That is, do you have, e.g., texts with umlauts in your data?)
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Le Wed, 24 Oct 2012 12:36:52 +0700,
Kim-Ee Yeoh a écrit :
> On Tue, Oct 16, 2012 at 9:37 PM, AUGER Cédric
> wrote:
>
> > As I said, from the mathematical point of view, join (often noted μ
> > in category theory) is the (natural) transformation which with
> > return (η that I may have erroneous
Is there a convenient way of handling a data structure with lots
of fields of different types that may or may not be filled in?
Something equivalent to
data D = D {a::Maybe A, b::Maybe B, c::Maybe C, …}
but with better space efficiency and a more convenient empty
object.
An easy alternative is
* Jon Fairbairn [2012-10-24 11:08:29+0100]
> Is there a convenient way of handling a data structure with lots
> of fields of different types that may or may not be filled in?
>
> Something equivalent to
>
> data D = D {a::Maybe A, b::Maybe B, c::Maybe C, …}
>
> but with better space efficiency
Hi Jon
On Wed, Oct 24, 2012 at 11:08:29AM +0100, Jon Fairbairn wrote:
> for each field, which is tedious (and O(n)). Obviously Templates
> would help, but is there an alternative I’ve missed?
perhaps something like:
data Type = Ta | Tb | Tc ...
data E= Ea A | Eb B | Ec C | ...
type D=
* Roman Cheplyaka [2012-10-24 13:55:17+0300]
> * Jon Fairbairn [2012-10-24 11:08:29+0100]
> > Is there a convenient way of handling a data structure with lots
> > of fields of different types that may or may not be filled in?
> >
> > Something equivalent to
> >
> > data D = D {a::Maybe A, b::Ma
What hiders according with my experience, the understanding of this
generalization are some mistakes. two typical mistakes from my side was to
consider an arrow as a function, and the consideration of m as a kind of
container, which it is not from the point of view of category theory.
a -> m b
On 2012-Oct-22 14:23 (-0700), Eugene Kirpichov wrote with possible deletions:
>
> fwd = foldr (\(x,y) -> M.insertWith (++) x [y]) M.empty $ S.toList g
>
> Use foldl' here, foldr is absolutely useless here and it only consumes
> the stack space as your operation is strict.
Thank you very much
The particular case from which the former is a generalization:
*instance Monad m => Monoid (a -> a) where*
*mappend = (.)*
*mempty = id*
*
*
Here the monoid is defined for the functions within the set of values of
type a. There are no null elements.
2012/10/24 Alberto G. Corona
> W
So far I used HDBC with mysql and sqlite3, in both cases with UTF8
encoded data (filenames including chinese characters, umlauts etc,
e.g.). (After connecting to mysql, I use the statement "set names utf8";
sqlite does not need this)
Am 10/24/12 11:10 AM, schrieb Johannes Waldmann:
Daniel va
On 24/10/12 12:08, Jon Fairbairn wrote:
Is there a convenient way of handling a data structure with lots
of fields of different types that may or may not be filled in?
Not sure about convenience, but here is a type safe solution with O(log n)
lookups and updates. The idea is to define a GADT
I'm trying to get around my problem (still stuck...).
I have really to call a function like this:
triggerEvent :: (Typeable e, Show e, Eq e) => Event e -> EventData e ->
State Game ()
This function simply execute an event given the corresponding data and
change the state of the game.
Now as explai
Hi,
On behalf of the cabal contributors, I'm proud to announce bugfix
releases of Cabal and cabal-install. Here's a complete list of changes
since the last release:
Since Cabal-1.16.0.1:
* Bump Cabal version number to 1.16.0.2
* Fixed warnings on the generated Paths module. The warnings are
gene
Thanks Johan and thanks to all the guys behind Cabal :)
Cheers,
A.
On Wed, Oct 24, 2012 at 09:42:48AM -0700, Johan Tibell wrote:
> Hi,
>
> On behalf of the cabal contributors, I'm proud to announce bugfix
> releases of Cabal and cabal-install. Here's a complete list of changes
> since the last
Hi Corentin
It looks like you are writing the event handler on the server side. If
so, the range of events you can handle is fixed to just those you
implement handlers for - having an openly extensible event type is
useless if this is the case.
Ignoring client/server for a moment, a function (Sta
Anyone know of a similar course to the coursera scala one for haskell ?
https://www.coursera.org/course/progfun
Quite interesting online course that has graded assignments.
Anything similar or anyone considering doing something similar for
haskell ?
Thanks
Graham
__
In case you haven't seen it, there is an intro to Haskell video series
by Erik Meijer on Channel9. There aren't any graded assignments or
anything like that, but I found it to be excellent without those.
[1]
http://channel9.msdn.com/Series/C9-Lectures-Erik-Meijer-Functional-Programming-Fundamenta
Dear all,
in an effort to Cabalize the Helium compiler and make it available on Hackage,
it would
be helpful to have an example of a Cabal file that shows how to deal with
compilation
of platform dependent C-code. Anybody out there who has a sample for me?
best,
Jurriaan Hage
I can see that the required effort would be prohibitive, but after thinking
about this some more I do think there are a couple of nice advantages:
1) Quizzes and graded assignments offer some structure to self study, and
having some form of feedback/validation when you first get started is
helpful
I'm taking it primarily because it is taught by the guy who made the
language. I mean how cool is that? He is very smart and certainly blows
any other lecturer I've ever had out of the water. If SPJ were doing a
haskell course I'd sign up for that too in a heart beat.
There's also a slim possib
Jon Fairbairn cl.cam.ac.uk> writes:
>
>
> Is there a convenient way of handling a data structure with lots
> of fields of different types that may or may not be filled in?
>
Hi Jon, if your question had appeared in a database forum, the answer would
be ...
Sounds like you need to do normal-
Hey!
I was doing similar things with my project "haskellion" ( which I know
you've seen because you're the only one that's commented on it -
http://www.youtube.com/watch?v=gn_ZZiXVlNY&feature=plcp ). I'm not
planning on getting back to work on it anytime soon (there's way too
much Haskell stuff I
You've got a bunch of great answers, if there's no rhyme or reason to
which fields are missing.
If, on the other hand, they will tend to be present or absent in
groups, you could decompose your data-structure a bit, for fast
lookups, good space efficiency, and maybe even slightly more
interesting
Hi,
Here are two examples:
a) unix-compat has one:
https://github.com/jystic/unix-compat/blob/master/unix-compat.cabal
and
b) Network library has a platform specific cabal:
https://github.com/haskell/network/blob/master/network.cabal
Kindly note that network also expects a configure script to run
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