Interesting idea. It seems like building this on top of REPA would save a
lot of work, since it has a native notion of "rank" encoded in the type
system. I'd then see the APL-like combinators as a "niche" API for REPA,
rather than as a library of their own. And of course, you'd get
parallelization
The higher universe levels are mostly "used" to stave off logical paradoxes
in languages where you care about that kind of stuff. In a fundamentally
impredicative language like Haskell I don't see much point, but I'd be
happy to find there is one :)
On Thu, Aug 1, 2013 at 4:55 PM, Wvv wrote:
>
It seems very similar to Ryan Ingram's post a few years back
(pre-TypeNats):
http://www.haskell.org/pipermail/haskell-cafe/2009-June/062690.html
The main difference is that he introduces the "knowledge" about zero vs.
suc as a constraint, and you introduce it as a parameter. In fact, his
induction
Considering that the GHC FFI is already built on libffi (I'm reasonably
sure) it seems unnecessary for the Hackage library to depend on an external
version. Is it not already getting linked in?
On Sun, Feb 17, 2013 at 6:53 PM, Ryan Newton wrote:
> > The scenario is pretty simple. I generate C
Although I agree that Functor should be a superclass of Monad, the two
methods of the Monad typeclass _are_ sufficient to make any instance into a
Functor in a mechanical/automatic way. The language may not know it, but
return/bind is equivalent in power to fmap/return/join. Apart from bind
being e
Shouldn't you have
IxZero :: Ix (CtxCons ty ctx) ty
instead of
IxZero :: Ix ctx ty
On Fri, Sep 21, 2012 at 8:34 AM, Florian Lorenzen <
florian.loren...@tu-berlin.de> wrote:
> -BEGIN PGP SIGNED MESSAGE-
> Hash: SHA1
>
> Hello cafe,
>
> I have the following GADT definitions capturing th
That doesn't require existential quantification, but it'll need Rank-2
types if you ever do anything with Job. Unfortunately, a universally
quantified Job like what you wrote (or what Magicloud seems to want) is
only inhabited by the empty Map.
An existentially quantified Job, as you might get wit
On Fri, May 25, 2012 at 3:07 AM, . wrote:
> The gpl is sort of my default license. I know it is a little
> restrictive, so if that keeps people (if any) from contributing, I will
> change the license. As far as I can see, I would be able to change it to
> lgpl then, but not to bsd.
>
>
I'm no law
given Iso a c and Iso
b dusing your class.
I'm not sure I'd bundle the two parts together, but I'd call your
pairmethod (or the class it lives in) something like congruent or
ProductsRespectThisRelation :)
Dan
On Tue, May 8, 2012 at 3:15 PM, Daniel Peebles wrote:
> FullBinar
FullBinaryTreeRelation? :P
On Tue, May 8, 2012 at 1:36 PM, MigMit wrote:
> Hi café, a quick question.
>
> Is there a somewhat standard class like this:
>
> class Something c where
>unit :: c () ()
>pair :: c x y -> c u v -> c (x, u) (y, v)
>
> ?
>
> I'm using it heavily in my current pro
Your problem is that you're including the (i, j) in your array element
type, when you really only want it to be in your index type (I assume).
This would not normally be an issue, but an unboxed array doesn't work on
an element type of ((Int, Int), Double).
You might consider instead making a new
On Fri, Apr 13, 2012 at 7:49 AM, Johannes Waldmann <
waldm...@imn.htwk-leipzig.de> wrote:
> type Computer a b = ( a -> IO ( Maybe b ) )
> type Transformer a b c d = Computer a ( b, c -> d )
Computer looks like Kleisli (MaybeT IO), which would be a valid instance of
Arrow.
_
I doubt anyone will mind too much, but you probably want to stick to the
category theory that is obviously applicable to Haskell (and ideally
talk/ask about how it applies). Questions about initial algebras and
Lambek's lemma will probably get decent responses, whereas globe categories
and anafunct
There are many reasons, but some of the more cited ones are that (<>) will
break less code than (++) would, since (++) is ubiquitous and (<>) is most
used in some pretty printers. Yes, mappend's type can be refined to that of
the current list (++), but the increased polymorphism still has the
poten
I'd like to see more statistics work, definitely. Bryan's statistics
library is excellent, but Ed Kmett has been talking about some very
interesting approaches to sampling from complicated distributions, which
I'd like to see implemented eventually in a library.
On Wed, Mar 21, 2012 at 1:24 PM, Be
A more subtle issue is that there's some sort of memory leak that arises
when you can't instruct the GC to follow projection functions of data
types. I believe the GHC heap representation has a built-in notion of these
forwarding closures and the GC follows them when possible, but most VM GCs
are j
This thread pretty much exemplifies why many people don't bother with this
mailing list anymore.
On Sun, Jan 1, 2012 at 7:00 PM, AUGER Cédric wrote:
> Le Sun, 1 Jan 2012 16:31:51 -0500,
> Dan Doel a écrit :
>
> > On Sun, Jan 1, 2012 at 3:26 PM, Ketil Malde wrote:
> > > Chris Smith writes:
> >
Not that I know of, but I would like them too. There are a few bindings to
yices, but I don't think yices has the feature I want in it.
On Thu, Dec 15, 2011 at 1:04 PM, Dimitrios Vytiniotis <
dimit...@microsoft.com> wrote:
>
> I've a quick question:
>
> Are there Haskell wrappers for the Z3 C API
I like it!
On Wed, Nov 16, 2011 at 1:01 AM, heathmatlock wrote:
> I liked Go's mascot, and I figure it couldn't hurt to have our own. I
> spent the past hour making this:
> http://i.imgur.com/Mib6Q.png
>
> What do you think?
>
> --
> Heath Matlock
> +1 256 274 4225
>
> ___
Yes, it does. You can only use members of the Elt class in repa arrays, and
Elt has Unbox as a superclass.
On Thu, Nov 10, 2011 at 5:03 PM, Yves Parès wrote:
> Does Repa always use unboxed Vectors?
> But a Repa array can store any element, so how does it handles types which
> haven't an unboxed
Have you seen Adam Megacz's work on generalized arrows? I think he proposes
to kill arr and has done a decent amount of work on it.
On Mon, Oct 31, 2011 at 8:33 PM, Ryan Ingram wrote:
> I know it's a bit of an 'intentionally provocative' title, but with the
> recent discussions on Arrows I thoug
int out idiom brackets (an analog for
> do-notation for Applicative functors) which have been introduced in
> some Haskell-related languages. Examples are Idris
> (http://www.cs.st-andrews.ac.uk/~eb/Idris/donotation.html) and SHE
> (http://personal.cis.strath.ac.uk/~conor/pub/she/idio
Good idea! I'd forgotten about monad comprehensions.
On Sun, Sep 4, 2011 at 3:11 AM, Shachaf Ben-Kiki wrote:
> On Sat, Sep 3, 2011 at 19:34, Daniel Peebles wrote:
> ...
> > Of course, the fact that the return method is explicitly mentioned in my
> > example suggests that
n 4 September 2011 12:34, Daniel Peebles wrote:
> > Hi all,
> > For example, if I write in a do block:
> > x <- action1
> > y <- action2
> > z <- action3
> > return (f x y z)
> > that doesn't require any of the context-sensitivty that Monads give
Hi all,
I was wondering what people thought of a smarter do notation. Currently,
there's an almost trivial desugaring of do notation into (>>=), (>>), and
fail (grr!) which seem to naturally imply Monads (although oddly enough,
return is never used in the desugaring). The simplicity of the desugar
And as Daniel mentioned earlier, it's not at all obvious what we mean by
"bits used" when it comes to negative numbers. GMP pretends that any
negative number has infinite bits in the two's-complement representation.
Should we count the highest _unset_ bit when the number is negative?
Or to put it
I haven't come across unimodular matrices before, but according to the
definition on wikipedia it seems fairly straightforward to implement a naive
algorithm to decide it.
Also, have you considered trying IRC for these sorts of short questions? The
#haskell IRC channel on freenode is helpful and s
Hey, I think you forgo
On Wed, Jun 22, 2011 at 12:20 AM, Arnaud Bailly wrote:
> Hello,
> I ha
>
> ___
> Haskell-Cafe mailing list
> Haskell-Cafe@haskell.org
> http://www.haskell.org/mailman/listinfo/haskell-cafe
>
___
Why not make it unlossy and have:
trans :: (Ord k, Ord a) => Map k a -> Map a (Set k)
On Thu, Jun 16, 2011 at 9:10 AM, Johan Tibell wrote:
> On Thu, Jun 16, 2011 at 3:01 PM, Dmitri O.Kondratiev
> wrote:
> > Hi,
> > Data.Map has many great functions, yet I could not find the one that
> allows
Isn't gcc just used for its assembler and object file creation, these days,
now that via-C is deprecated? Or are there other parts of it that are
needed?
On Mon, Jun 6, 2011 at 10:47 AM, Malcolm Wallace wrote:
>
> On 6 Jun 2011, at 13:49, Lyndon Maydwell wrote:
>
> > I would be fantastic if XCode
I thought Apple had stopped bundling the dev tools with installation DVDs?
On Fri, Jun 3, 2011 at 4:32 PM, Judah Jacobson wrote:
> Hi John,
>
> You should be able to install the Apple Developer Tools directly from
> one of the software installation DVDs that come with the Mac. If
> you're not do
Do you have some sort of link aggregator that auto-posts to haskell-cafe?
On Sat, May 21, 2011 at 12:09 AM, KC wrote:
> Extension for "Pearls of Functional Algorithm Design" by Richard Bird,
> 2010, page 25 #Haskell
>
>
> --
The way I understand it, you're saying not that we shouldn't be doing it
this way (since it isn't centrally managed, it's the only possible way), but
that we shouldn't be "bragging" (for lack of a better word) that we have
lots of libraries that do a specific thing. Or if not that, then at least
th
It's a hack by design, to work around libraries that do the wrong thing.
On Fri, Mar 11, 2011 at 4:07 PM, Henning Thielemann <
lemm...@henning-thielemann.de> wrote:
>
> On Fri, 11 Mar 2011, Daniel Peebles wrote:
>
> Check out the spoon package on hackage. It's
Check out the spoon package on hackage. It's designed for these kinds of
situations, and will wrap up common user-generated "pure" exceptions into a
Maybe (and will return Nothing in the cases you describe)
-Dan
On Fri, Mar 11, 2011 at 11:04 AM, Daniel Díaz wrote:
> Hi, cafe,
>
> I'm working in
3:09 PM, Daniel Peebles wrote:
> Have you submitted a bug report to GHC of why it can't work with the
> current integer-gmp binding? I know that GHC's collector is collecting
> MPFR's temporary data, but maybe it'd be good to get a discussion going on
> what can be
Have you submitted a bug report to GHC of why it can't work with the current
integer-gmp binding? I know that GHC's collector is collecting MPFR's
temporary data, but maybe it'd be good to get a discussion going on what can
be done to stop it from doing this even in the context of the existing
inte
Have you tried it? It's completely addictive (and takes up a big chunk of my
free time). I'm not sure it'll appeal to everyone, but I wouldn't dismiss it
off-hand like that.
On Mon, Feb 28, 2011 at 10:16 AM, Colin Adams wrote:
> On 28 February 2011 14:59, Tom Hawkins wrote:
>
>> I have been wan
Knowing nothing about the package or its code, it looks like a typo to me.
The stdint.h naming of types would have it be uint64_t, not uint_64t. Could
that be it?
On Fri, Feb 4, 2011 at 6:00 AM, Michael Snoyman wrote:
> Hi everyone,
>
> Does anyone else have trouble installing the AES package on
This is indeed very strange. On my latest GHC 7 (built a couple of days ago)
it does the right thing when compiled, but in GHCi it behaves as you
describe. I have no idea, frankly.
On Thu, Feb 3, 2011 at 8:44 PM, Steffen Schuldenzucker <
sschuldenzuc...@uni-bonn.de> wrote:
>
> Dear cafe,
>
> does
And by "works", I mean, ListT is is a monad only if the internal monad is
commutative.
On Fri, Jan 28, 2011 at 2:46 PM, Daniel Peebles wrote:
> Beware of ListT. It only works if your internal monad is commutative, which
> IO is not. (Maybe would work, for example)
>
>
>
Beware of ListT. It only works if your internal monad is commutative, which
IO is not. (Maybe would work, for example)
On Fri, Jan 28, 2011 at 2:41 PM, Chris Smith wrote:
> On Fri, 2011-01-28 at 11:20 -0800, michael rice wrote:
> > The first and third work, but not the second. Why?
>
> When you
Seems like you'd want x <- getArgs and x == ["debug"] rather than the
irrefutable pattern match.
On Sun, Dec 26, 2010 at 3:04 PM, Michael Snoyman wrote:
> I think something like this would work:
>
> myFlag = unsafePerformIO $ do
>[x] <- getArgs
>return $ x == "debug"
>
> In general, unsaf
I remember seeing this very discussion about pointed being disjoint from
functor just recently on one of the various haskell mailing lists. But as
for my opinion on it, because there's no real way of specifying any laws for
pointed without functor. With functor and pointed, you can say that you
exp
For me, mostly naming. Cofunctor isn't the right name for it, and comap,
while short, feels wrong. Contrafunctor feels better but is also cumbersome.
No problems with Comonad, though.
On Thu, Dec 23, 2010 at 9:16 PM, Mario Blažević wrote:
>
> On Thu, Dec 23, 2010 at 5:25 PM, Stephen Tetley
> wr
efully.
On Thu, Dec 23, 2010 at 12:30 PM, Ryan Ingram wrote:
> On Thu, Dec 23, 2010 at 8:19 AM, Daniel Peebles
> wrote:
> > Simulating bottoms wouldn't be too hard, but I don't think the statement
> is
> > even true in the presence of bottoms, is it?
>
> Isn&#
I think it's pretty legit. You aren't actually making a claim about the
values in the tree but I think parametricity handles that for you,
especially since you have existential types for the payload at every tree
level (so you can't go shuffling those around).
The only thing missing (and that you
Write out more types and it'll get more clear.
f is [Int] -> IO [Int]
lst is f applied to Num a => [a], so it is of type IO [Int]
fmap is applied to lst, which means it's "stepping inside" the IO. That
means it's applying +1 to [1,2,3,4,5], which doesn't make much sense unless
you have a Num ins
Have you considered moving these packages that are unrelated to web
development into a separate namespace? I know that I never considered
looking under the happstack namespace simply because I never do webapps.
On Thu, Dec 16, 2010 at 5:09 PM, Jeremy Shaw wrote:
> Hello,
>
> You should use happs
I haven't tested this idea, but it occurred to me that this might be a good
place for data families:
data Z = Z
newtype S n = S n
-- Some nastiness to avoid having to see into the future?
type family Pred n :: *
type instance Pred (S n) = n
type instance Pred Z = Z
class MyDataClass ver where
Oh yeah, the 2.0 stuff that snobby techies love to hate :) hrrmpf back in my
day we programmed in binary using a magnetized needle on the exposed tape! I
don't need any of this newfangled bull.
I kid! But I am curious to see why people are so opposed to this stuff? The
attitude "I can't see an
There's a lot of interesting material on this stuff if you start poking
around :) http://www.cs.kent.ac.uk/people/staff/sjt/TTFP/ might be a good
introduction.
I'd consider typeclasses to be "sets" of types, as you said, but more
generally, a relation of types. In that view, an MPTC is just an n-a
ишет:
> >>
> >> Just after hitting the button send, it appeared to me that fromInt was
> >> not obvious at all, and probably impossible.
> >> Not sure I understand your answer though: What would be the second
> >> parameter (forall n . (Nat n) => n
The best you can do with fromInt is something like Int -> (forall n. (Nat n)
=> n -> r) -> r, since the type isn't known at compile time.
On Thu, Nov 18, 2010 at 2:52 PM, Arnaud Bailly wrote:
> Thanks a lot, that works perfectly fine!
> Did not know this one...
> BTW, I would be interested in the
If I were to guess, I'd say it's because there are two major "spaces" in
Haskell, the type level and the value level. They never interact directly
(their terms are never juxtaposed) so there's not much chance for confusion.
"Typeclass constructors" and type constructors do however live in the same
Hmm, strange. I have a project that uses data families with dozens of
constructors per "clause"/instantiation of the type function. I use GADT
syntax to define them though as they also refine one of the parameter type
variables. Never had any issues with it, although I haven't tried building
that p
Looks like http://www.haskell.org/cabal/FAQ.html has a description of your
problem!
2010/11/3 André Batista Martins
> Hi Johan,
> i already try use Criterion but i couldn't install with cabal :S i get
> error:
>
>
> cabal install criterion
> Resolving dependencies...
> cabal: dependencies confl
That is a result of the implementation of the specific Monad instance, and
that does depend on the type, as you say (but it isn't determined for
sequence(_) specifically).
Nothing >>= f = Nothing
Just x >>= f = f x
is why a Nothing "pollutes" the sequenced lists of Maybes. If Maybe is a
Monad rep
Speaking of MagicHash, is it really necessary to take an operator with
"potential" like (#) just to keep primitive symbols separate from the rest?
At least from my 2010 Haskell learner perspective, it seems odd to create a
whole language extension/lexical change just for that purpose.
On Thu, Oct
>
> There is this one posters who likes to repeatedly point out how none of his
> programs ever needed email, so how could it be a problem then. Well good for
> him, but in my experience it's needed.
This is the main issue I think people had with your original posts. You say
"good for him, but I
I'm occasionally working on making a friendly yet performant library that
simultaneously builds parsers and generators, but it's non-trivial. If you
want to see the general idea, there's a Functional Pearl on pickler
combinators from a few years back that you can probably play with.
But for a real
Just out of curiosity, why do you (and many others I've seen with similar
proposals) talk about additive monoids? are they somehow fundamentally
different from multiplicative monoids? Or is it just a matter of notation?
When I was playing with building an algebraic hierarchy, I picked a
"neutral" o
Hi all,
Might it be worthwhile to take the elected "superusers" on
haskellers.comand let them police the skills list? It's become rather
messy, with overly
broad terms like "Mathematics" in it, as well as overly specific ones like
"Other languages I know: C# .NET, XSLT, Microsoft SQL Server, XML,
One option could be something like:
data Z
data S n
data Vec n a where
Nil :: Vec Z a
Cons :: a -> Vec n a -> Vec (S n) a
data Length n where
One :: Length (S Z)
Two :: Length (S (S Z))
Seventeen :: Length (S (S (S (S (S (S (S (S (S (S (S (S (S (S (S (S (S
Z)
data Fixe
Is the language secret? because I'm sure lots of people would like to help
on this mailing list, but you'd need to tell us what help you need first :)
On Sun, Oct 3, 2010 at 8:38 PM, Eduardo Ribeiro wrote:
> Hello,
> I 'm developing a new language in haskell and I need someone to help me.
> Anyon
h I had a "list difference" feature
in twitter to figure out who's on his list and isn't on mine (and maybe vice
versa).
On Fri, Oct 1, 2010 at 5:04 PM, Magnus Therning wrote:
> On Fri, Oct 1, 2010 at 14:14, Daniel Peebles wrote:
> > Several haskellers have lists of haskell
Also, it is possible to add yourself to your own twitter list :)
On Fri, Oct 1, 2010 at 12:03 PM, Magnus Therning wrote:
> Now that there are lists/groups on Twitter
> (http://mashable.com/2009/11/02/twitter-lists-guide/) maybe one should
> be created one for Haskellers?
>
> I would do it, but it
Several haskellers have lists of haskellers, and most of them include Don,
I'd expect. I know my list does:
http://twitter.com/#!/copumpkin/haskell
Otherwise, there's a list of haskellers on the haskell wiki but I'm not
usure it's very up to date: http://www.haskell.org/haskellwiki/Twitter
On F
Have we put off the ultra-newbie by derailing his simple question into a
discussion on subtle issues he shouldn't care about this early on?
On Mon, Sep 20, 2010 at 3:49 PM, Daniel Fischer wrote:
> On Monday 20 September 2010 15:20:53, James Andrew Cook wrote:
> > On Sep 20, 2010, at 5:10 AM, Jean
Sounds awesome! Why not grab .org too? or was that taken?
On Thu, Sep 16, 2010 at 2:35 PM, Michael Snoyman wrote:
> On Thu, Sep 16, 2010 at 10:26 AM, Andrew Coppin
> wrote:
> > On 16/09/2010 08:52 AM, Michael Snoyman wrote:
> >>
> >> future it would be beneficial to the community to have this
>
ne of
this year's GSOC for example). I was just trying to show what this would get
us one step closer to :P
On Thu, Sep 16, 2010 at 11:47 AM, Ivan Lazar Miljenovic <
ivan.miljeno...@gmail.com> wrote:
> On 16 September 2010 17:00, Daniel Peebles wrote:
> > But maybe one day
As we were discussing in #haskell, it would have to be more involved than
just a taint bit. A listing showing the "taint sources" of a given package
would give you confidence in its good behavior.
For example, if my nice, pure package's taint list showed that my only taint
sources were through my
I was under the impression that the main reason GHC requires .hs-boot files
is that nobody has had the time or inclination to make it resolve circular
dependencies automatically, and not an intentional design decision to
encourage "good design".
On Tue, Sep 7, 2010 at 6:51 AM, Mathew de Detrich w
Is there a reason this belongs under the Data. prefix? Why not break it out
into Crypto, so future implementers of algorithms can also put their stuff
under there. Everything at some level can be seen as Data, and it would be
nice to start moving out of the overcrowded module hierarchy.
On Fri, S
What you're asking for is essentially a dependent type (something where a
type depends on a value). Haskell doesn't support these, but can approximate
them with GADTs:
{-# LANGUAGE GADTs, EmptyDataDecls, KindSignatures, Rank2Types #-}
data A
data B
-- The data constructors refine the type index
Interesting. I've come across this general idea/algorithm the factor graph /
sum-product algorithm papers[1] but I was wondering if you knew of any
implementations of it in haskell? I wrote one a while back but it was fairly
ugly and not as general as I'd have liked, so I never released it.
Thanks
The problem is that you have an existential `t` there, and two values of the
type Foo might not have the same `t` inside them.
What do you want to happen if someone writes Foo True == Foo "yep"?
The only real solution here is to parametrize your Foo type by the t that
lives within it, so you can
Sounds to me like we need a lazy Data.Text variation that allows UTF-8 and
UTF-16 "segments" in it list of strict text elements :) Then big chunks of
western text will be encoded efficiently, and same with CJK! Not sure what
to do about strict Data.Text though :)
On Tue, Aug 17, 2010 at 1:40 PM, K
There's a Fibonacci Heap: http://en.wikipedia.org/wiki/Fibonacci_heap
Not sure what else though :)
On Mon, Aug 16, 2010 at 11:14 PM, Antoine Latter wrote:
> On Mon, Aug 16, 2010 at 1:37 PM, Andrew Coppin
> wrote:
> >
> > This neatly leads us back to my second assertion: In all my years of
> >
>
> In the example above, fiblist is a global variable, so the answer to "when
> does it get freed?" would be "never". (I believe it's called a CAF leak.)
>
Is that actually true? I've heard lots of references to this, but I'm not
sure it is true. Sure, it's harder for it to get collected when eve
The existential is a pair where one component is a type, and the type of the
second component depends on the value (i.e., which type went in the first
component) of the first. It's often called a sigma type when you have full
dependent types.
So your exists a. (Int -> a) -> [Int] -> [a] type might
The Hummingbird is still ARM. ARM doesn't actually build any chips
themselves, and just license the architecture design out to people who do
make them. Most of the iPhone ARM chips are built by Samsung too.
Almost all the mobile devices I know of run ARM, so I think having a native
ARM generator w
Another interesting direction would be to use Matt Morrow's vaccum
infrastructure to make a neat, almost completely general, serialization
mechanism.
It's not safe, and can traverse any value that doesn't contain functions or
unevaluated thunks, but would be very helpful for sending values like `c
Great! I like it a lot, but a couple of minor suggestions regarding the
"tree" view of modules. I think it would be more attractive (and
space-efficient) to have them indent a little less and to provide some sort
of visual link, in the form of even subtle branches, from parents to
children. A bit l
It's a matter of perspective. Either the function you're FFI'ing to is
safe/unsafe or your use of it is safe/unsafe. The FFI spec seems to be using
the former, so if you think that the function you're calling is unsafe
(i.e., can call back into Haskell) then it blocks the world.
But I do think it'
Next up, binary obfuscation! Apple already uses these extensively in their
Fairplay code. Surely it isn't against the rules (yet?) to apply them to
your program before submitting it to the store? :P
On Wed, May 26, 2010 at 11:01 PM, Ben Lippmeier wrote:
>
> On 27/05/2010, at 9:01 AM, Edward Kmet
Of course, given that they have no way of determining that short of asking
for the source code (and hiring another thousand reviewers to read it) or
applying static analysis tools with heuristics to the programs. I really
doubt they do the latter, and the former is unrealistic.
Most people seem to
Djinn can't figure it out, and neither can I :P
2010/5/25 Günther Schmidt
> Hi Yitz,
>
> embarrassingly I was unable to deduce the implementation from the type
> signature, don't be tease man, show me what you got :)
>
> Günther
>
> Am 25.05.10 18:27, schrieb Yitzchak Gale:
>
> Günther Schmidt
Have you tried freopen on stderr?
On Fri, May 21, 2010 at 8:43 AM, Phyx wrote:
> Hi,
> I tried that, setting it to (\_ _ _ _ -> return ()) and it still did the
> same, also tried setting it to undefined to see whether the code that's
> printing the error is using it, and it didn't crash
> So I a
prefac is just a normal factorial function with recursion factored out. fix
prefac 5 gives 120, for example.
On Tue, May 4, 2010 at 12:13 AM, Ivan Miljenovic
wrote:
> On 4 May 2010 13:30, Luke Palmer wrote:
> > Here is a contrived example of what I am referring to:
> >
> > prefac f 0 = 1
> > pre
It's not an easy measurement to even define. There was a huge debacle
recently about a windows program that reported misleading numbers about used
memory. The fact that GHC has its own allocator and "hogs" OS memory (it
never returns it to the OS) might complicate the definition further. But in
gen
I believe numCapabilities (should be in IO, in my opinion, but that's
another discussion) will tell you the number of capabilities (native
threads) that have been given to the RTS. The measurement doesn't
necessarily have any connection to the number of physical cores or
processors in your machine.
I'm definitely not a design/color person, but has anyone considered using
kuler.adobe.com as a source of "nice" color schemes, since we seem to have
an issue coming up with attractive combinations?
On Tue, Apr 6, 2010 at 9:58 AM, Thomas Schilling wrote:
> Well, they make the wannabe-designer mist
You can actually write that type with impredicative polymorphism, but it
doesn't do what you seem to want: it makes a list of polymorphic values
(i.e., universally quantified ones, not existentially).
But that's going away soon, anyway...
On Sun, Feb 28, 2010 at 1:49 PM, Yves Parès wrote:
>
>
>
Given any functor you can get a monad for free!
data Free f a = Either a (f (Free f a))
Not sure about unfree, but there are cofree comonads that are pretty closely
related, and give you a comonad given a functor:
data Cofree f a = (a, f (Cofree f a))
I'm sure the more categorically minded can
It's not quite what you're asking for, but a very similar idea is the SHE
preprocessor: http://personal.cis.strath.ac.uk/~conor/pub/she/
Dan
On Mon, Feb 22, 2010 at 8:08 PM, Paul Brauner wrote:
> Hello,
>
> I remember seeing something like
>
> > typedata T = A | B
>
> somewhere, where A and B a
Interesting. Do you have any details on this? It seems like it would be hard
to express system of linear inequalities as a finite system of linear
equations.
Thanks,
Dan
2010/2/17 Matthias Görgens
> > As far as I can see, you'd use that for systems of linear equalities, but
> > for systems of l
As far as I can see, you'd use that for systems of linear *equalities*, but
for systems of linear *inequalities* with a linear objective function, it's
not suitable. I may be wrong though :)
On Tue, Feb 16, 2010 at 3:37 PM, Felipe Lessa wrote:
> On Tue, Feb 16, 2010 at 03:12:53PM
How would you use hmatrix? By linear programming I assume he means systems
of linear inequalities, as typically solved by the simplex algorithm. I too
am interested in this question (and the more general one of nonlinear
optimization)!
Thanks,
Dan
On Tue, Feb 16, 2010 at 2:54 PM, Felipe Lessa wro
>
> data Stack a = EmptyStk | Stk a (Stack a)
I find it amusing that the book defined a type that is exactly isomorphic to
the standard list (EmptyStk === [] and Stk === (:)). I guess it's just for
clarity?
On Thu, Feb 4, 2010 at 12:29 PM, Casey Hawthorne wrote:
> On Thu, 4 Feb 2010 09:07:28
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