I'm a bit curious
> * be reliable in the presence of async exceptions (solved by conduit,
> pipes-safe),
>
> * hold on to resources only as long as necessary (solved by conduit
> and to some degree by pipes-safe),
Are you aware of
http://okmij.org/ftp/Streams.html#regions
wh
But Haskell (and GHC) have existential types, and your prototype code
works with GHC after a couple of trivial changes:
> main = do
> W nd0 <- init
> wd0 <- addWatch nd0 "foo"
> wd1 <- addWatch nd0 "bar"
> W nd1 <- init
> wd3 <- addWatch nd1 "baz"
> printInotifyDesc nd0
> printInoti
I guess you might like then
http://okmij.org/ftp/Haskell/types.html#Prepose
which discusses implicit parameters and their drawbacks (see Sec 6.2).
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Mateusz Kowalczyk wrote:
> Is there a way however to do something along the lines of:
> > class Eq a => Foo a where bar :: a -> a -> Bool bar = (==)
> >
> > class Num a => Foo a where bar :: a -> a -> Bool bar _ _ = False
> This would allow us to make an instance of Num be an instance of Foo
> or
As far as I can tell, the only thing on that list not solved currently
by `pipes` is leftovers, but I will be releasing that very soon.
Hello everybody,
I'm trying to formulate the stream processing problem, which doesn't
seem to be solved fully by the currently existing patterns. I'm
experimen
A value has an indefinite extent if it's lifetime is independent of any
block of code or related program structure, think malloc/free or new/gc.
A value has a dynamic extent if is lifetime is statically determined
relative to the dynamic execution of the program (e.g. a stack variable):
in this
On Fri, May 10, 2013 at 3:31 PM, Leon Smith wrote:
> On Fri, May 10, 2013 at 5:49 PM, Alexander Solla wrote:
>
>> I'm not sure if it would work for your case, but have you considered
>> using DataKinds instead of phantom types? At least, it seems like it would
>> be cheap to try out.
>>
>>
>> ht
I'm looking for the version of haskell platform that was "supposed" to be
released May 6. It seems like it isn't out yet. What's preventing this from
happening, and is there anything I can do to help?
Regards,
- Clark
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On Fri, May 10, 2013 at 5:49 PM, Alexander Solla wrote:
> I'm not sure if it would work for your case, but have you considered using
> DataKinds instead of phantom types? At least, it seems like it would be
> cheap to try out.
>
>
> http://www.haskell.org/ghc/docs/7.4.2/html/users_guide/kind-poly
I'm not sure if it would work for your case, but have you considered using
DataKinds instead of phantom types? At least, it seems like it would be
cheap to try out.
http://www.haskell.org/ghc/docs/7.4.2/html/users_guide/kind-polymorphism-and-promotion.html
On Fri, May 10, 2013 at 12:52 PM, Leon
On Fri, May 10, 2013 at 9:04 AM, MigMit wrote:
> With that kind of interface you don't actually need existential types. Or
> phantom types. You can just keep Inotify inside the Watch, like this:
>
Right, that is an alternative solution, but phantom types are a relatively
simple and well underst
On Fri, May 10, 2013 at 9:00 AM, Andres Löh wrote:
> > This twist is very simple to deal with if you have real existential
> types,
> > with the relevant part of the interface looking approximately like
> >
> > init :: exists a. IO (Inotify a)
> > addWatch :: Inotify a -> FilePath -> IO (Watch a
On May 9, 2013, at 10:36 PM, Conal Elliott wrote:
> BTW, have you see the new paper The constrained-monad problem? I want to
> investigate whether its techniques can apply to Category & friends for linear
> maps and for circuits. Perhaps you’d like to give it a try as well. I got to
> linear m
Hi Mateusz,
It's not directly possible to write a class with a choice of
superclasses; as you point out, it's not really clear what that would
mean. One workaround, though it might not be sensible in practice, is
the following.
> {-# LANGUAGE ConstraintKinds, GADTs #-}
First, reify the constrain
Hello everybody,
I'm trying to formulate the stream processing problem, which doesn't
seem to be solved fully by the currently existing patterns. I'm
experimenting with a new idea, but I want to make sure that I don't miss
any defining features of the problem, so here is my list. A stream
proces
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Greetings,
We can currently do something like
> class (Num a, Eq a) => Foo a where bar :: a -> a -> Bool bar =
> (==)
This means that our `a' has to be an instance of Num and Eq. Apologies
for a bit of an artificial example.
Is there a way however t
Maybe I understand the problem incorrectly, but it seems to me that you're
overcomplicating things.
With that kind of interface you don't actually need existential types. Or
phantom types. You can just keep Inotify inside the Watch, like this:
import Prelude hiding (init, map)
import Data.IORef
Hi.
> So the natural question here is if we can employ the type system to enforce
> this correspondence. Phantom types immediately come to mind, as this
> problem is almost the same as ensuring that STRefs are only ever used in a
> single ST computation. The twist is that the inotify interfac
I've been working on a new Haskell interface to the linux kernel's inotify
system, which allows applications to subscribe to and be notified of
filesystem events. An application first issues a system call that returns
a file descriptor that notification events can be read from, and then
issues f
On 2013-05-09 17:04, Hans Georg Schaathun wrote:
> Does anyone have experience with integrating Haskell and Java?
> I have done some searching, finding a lot of pointers but hardly
> anything in terms of evaluation, successes, or caveats.
>
> From what I see Frege looks promising, arguably not
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