many of the ideas of purely functional, typeful programming have been
carried into newer languages and language features. including C#, F#, Java
Generics, LINQ, Perl 6, Python, and Visual Basic 9.0.
typeful programming and Python in the same sentence? ^^
More seriously, the influence of Haskell
Personally, I came much less against UndecidableInstances when I was trying
to do OOP in Haskell than when I was trying do Prolog-like things at the
type level.
Things like transitive relations: (If a type B contains an A, and if C
contains B, then C contains A, and so on).
I kind of abandonned
Is this badly designed code that tries to mimic OO in a functional
setting? If the answer is yes, how could I achieve same result (eg. testing
the code that does command REPL) without defining type classes?
Why would that be badly designed? And why would that be more OO? IMO it is a
perfectly
...and the other one being operational (which I find simpler).
2011/6/8 Brandon Allbery allber...@gmail.com
On Tue, Jun 7, 2011 at 16:16, Arnaud Bailly arnaud.oq...@gmail.com
wrote:
For example, while designing some program (a game...) I defined a type
class
thus:
class (Monad io) =
Well, yes add1 and add2 are equivalent. You can use either one or the other.
The type annotation can be read:
for all type 'a' such as 'a' is an instance of class Num, there exists a
function add1 that takes an 'a' and returns an 'a'.
2011/6/5 Patrick Browne patrick.bro...@dit.ie
Are the
Haskell at work.
If anyone is curious, the project is essentially a service that determines
the optimum order for a comparison shopping engine.
On Thu, Jun 2, 2011 at 11:52 AM, Yves Parès limestr...@gmail.com wrote:
Learning Haskell will pay off much less than learning PHP, if your goal
Why not hierarchical tags? (Tags organized in directories, well, basically,
tags with slashes or dots)
This is the most flexible IMHO.
2011/6/4 Vo Minh Thu not...@gmail.com
2011/6/4 Tillmann Vogt tillmann.v...@rwth-aachen.de:
Hi,
There are some categories on Hackage that have become so
*Touché.* Nice one.
2011/6/4 Albert Y. C. Lai tre...@vex.net
On 11-06-04 02:20 AM, Roman Cheplyaka wrote:
It is, for my taste, a good comment marker, because of its resemblance
to a dash. It makes the code look like real text:
let y = x + 1 -- increment x
COBOL is real text, if that
I've enjoyed reading Simon Marlow's new tutorial on parallel and
concurrent programming
I am interested: where I this tutorial?
2011/6/3 John D. Ramsdell ramsde...@gmail.com
I've enjoyed reading Simon Marlow's new tutorial on parallel and
concurrent programming, and learned some surprisingly
Learning Haskell will pay off much less than learning PHP, if your goal is
to find a job.
Amen.
I cannot agree with this for practical reasons. I'm using Haskell for
real world commercial applications, and I'm very productive with it.
I wish so much I could say that... Out of curiosity,
Maybe you are looking for a more generic way to concatenate it:
There is
foldhttp://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Foldable.html#v:fold::
(Foldable t, Monoid m) = t
m -
mhttp://hackage.haskell.org/packages/archive/base/latest/doc/html/Data-Foldable.html#v:foldin
Hello Café,
An idea came to me: unless the compiler notices that stuffA and stuffB are
equivalent, would it be correct to suppose that A is better than B?
stuffA x = if someComputationallyExpensiveTest x
then doSomething else doSomethingElse
stuffB x y = if someComputationallyExpensiveTest x
come on! it's fun! i can write foldr with foldl!
And when you try to explain that to your java-ITC-formatted friends, they
utterly surprisingly seem not to care about it ^^
2011/5/31 Adrien Haxaire adr...@adrienhaxaire.org
Le 31/05/2011 21:15, Alberto G. Corona a écrit :
Haskell is an
No, I think Artyom meant assuming IO is lazy.
He intended to show that, indeed, it is not, or else side-effects would
never be performed
2011/5/31 Scott Lawrence byt...@gmail.com
On 05/31/2011 04:20 PM, Artyom Kazak wrote:
Suppose iRecurse looks like this:
iRecurse = do
x -
It can introduce space leaks if the computationally expensive test is
replaced with a reference to a space expensive value.
You mean if the rest of stuffX's body keeps a reference to that value, I
suppose? (I suppose, or else that value would be useless).
Ok, so GHC does detect that case and
Yes, for my first example, the kind is wrong. I knew it, I just wrote it to
show, not to be correct Haskell, sorry.
@Antoine: Well, yes, internally, I think this is how it will be implemented.
What I wondered was if arrows would provide a nice interface to it.
@Stephen: Resumption monads? It
Hello,
For the purposes of a simple strategy game, I'd like to build an EDSL that
expresses missions. A mission could be represented as a state machine.
With basic bricks such as actions (MoveTo, ShootAt...) or tests
(EnemiesAround, LowHealth...), I could (ideally dynamically) build some
So it seconds my initial point: you can't store the size because it has no
sense.
2011/5/25 Ketil Malde ke...@malde.org
Richard O'Keefe o...@cs.otago.ac.nz writes:
Then tell me, why does calculating the length of a (Haskell)
list has O(n) complexity.
Because it is a rather rare
Why did you ask a question which you yourself characterize as ignorant?
Juan, I think it is the kind of question whose answer is obvious to people
with at least a little practice of the language.
For instance, one of my friends asked me once why the operation of
calculating the length of list
For Scala, I think it's really due to the type of people that are
attracted to the community. My impression is that more people are coming
from Java programming than from academia.
Java developpers who whould be interested in doing things in a clean,
expressive and manageable way?
Maybe
pointed it out.
2011/5/24 Johannes Waldmann waldm...@imn.htwk-leipzig.de
Yves Parès limestrael at gmail.com writes:
For instance, one of my friends asked me once why the operation of
calculating the length of list has an O(n) complexity,
since to his opinion, you could just store the size
Will the same etiquette work when we start to get lots of questions from
Java programmers? :)
If you mean will we have to maintain the same etiquette? then, sadly, yes.
(And I said we were done trolling! ;) )
2011/5/24 Tom Murphy amin...@gmail.com
Firstly, I would definitely like to second
it can involve several qualified imports and time researching
ByteStrings/Lazy ByteStrings/ByteString.Char8
Evan is right, the right way is to use the text package (plus, it is part of
the platform and is simple to use), or at least the utf8-string package
(encode/decode functions). I personnaly
Hello all,
By the way, is there any reason to prefer package 'vector' over package
'array'? Do they just provide different interfaces to similar
functionnalities or are there real performance stakes?
I personnaly prefer Data.Array, since:
- It gives the possibility to index with something else
Probably because in the instance of Monad Either, fail has not been
overloaded, and still has its default implementation:
fail = error
Whereas runErrorT explicitely catches the exception.
2011/5/16 Gracjan Polak gracjanpo...@gmail.com
Hi all,
A why question: Why:
Control.Monad.Error
Talking about that, what are the differences between cabal-install and
cabal-dev? Is cabal-dev (which I've never used nor installed) more suited
for incremental development?
2011/5/12 Jason Dagit dag...@gmail.com
On Wed, May 11, 2011 at 6:13 PM, Gregory Crosswhite
Hello Café,
I'm trying to get some modular data types.
The idea that came to me is that I could stack them, for instance :
data Character a = Character { life :: Int,
charaInner :: a }
data Gun a = Gun { firepower :: Int,
gunInner :: a }
data
I meant:
chara = Character 100 $ Armor 40 $ Gun 12 *()*
2011/4/6 Yves Parès limestr...@gmail.com
Hello Café,
I'm trying to get some modular data types.
The idea that came to me is that I could stack them, for instance :
data Character a = Character { life :: Int
(Gun b) a) = a - Gun b
itsGun = content
You were missing a mechanism to extract the inner value from your
datatypes.
- Job
On Wed, Apr 6, 2011 at 2:57 PM, Yves Parès limestr...@gmail.com wrote:
Hello Café,
I'm trying to get some modular data types.
The idea that came to me is that I
Hello,
For the purpose of a simple game, I'm looking for a simple way to get agents
communicating with each other, with agents possibly running on different
threads:
Basically, an agent is Agent :: * - *, since it is parameterized with the
type of messages it can receive, and can make two basic
Then if you turn :
fs True = True
fs x = True
to:
fs x = case x of
True - True
x' - True
Is it still strict, or does 'fs' wrap the case test and defer evaluation?
2011/4/1 o...@okmij.org
Daniel Fischer wrote:
If you have a strict function, you may evaluate its argument eagerly
Just to be sure, because I am not quite familiar with the dark hairy
internals of GHC:
Of course, given a type signature that allows strictness to be inferred.
You mean a signature with no type variables and types that are know to GHC
as being strict?
(Like Int - Int - Int instead of (Num a) =
If I'm not wrong :
sum [1..n] = (n² + n)/2
2011/3/30 Daniel Fischer daniel.is.fisc...@googlemail.com
On Wednesday 30 March 2011 16:39:49, Gilberto Garcia wrote:
Hi Haskellers,
I was solving this problem from project euler to study haskell.
I came up whit the following solution and I
Hello,
To access a haskell type from C code, do we have to make this type instance
of Storable (and so to also define an homomorph structure on the C side), or
does FFI specifies some C function to enable C code to access the fields, or
even some GHC-specific functions? (Even if I'd prefer a
Actually, Tako:
data Shape = forall a. Drawable a = Shape a
Can also be done with GADTs:
data Shape where
Shape :: Drawable a = a - Shape
If wouldn't know if one approach is preferable to the other or if is just a
matter of taste.
Your problem, Tad, is kind of common. I ran
contains Shape, your class Shapeful
must provide all the necessary information (but that is kind of usual in
Haskell).
The advantage here is that you generalize the position (sx and sy fields)
which are no longer duplicated within Rectange and Circle.
2011/3/29 Yves Parès limestr...@gmail.com
Actually
You could turn 'insertSubTree' into and operator, and shorten insertLeaf
createTree = do
Fruits + do
leaf Apple
leaf Mango
Arbitrary + do
leaf 1
-- and so on...
It's a little bit more concise.
But I fail to see the use of TreeContext
You are better to use simple typeclasses. It depends on what you are trying
to do, but when I want an open type, I use classes + type families.
2011/3/18 Stephen Tetley stephen.tet...@gmail.com
On 18 March 2011 13:31, Grigory Sarnitskiy sargrig...@ya.ru wrote:
Anyway, a new question arose.
http://steve-yegge.blogspot.com/2010/12/haskell-researchers-announce-discovery.htmlhttp://steve-yegge.blogspot.com/2010/12/haskell-researchers-announce-discovery.html
I love the sentence We crafted a fake satirical post lampooning Haskell as
an unusable, overly complex turd -- a writing task
your subtype relation says A - B is a subtype of C -D whenever
A is a supertype of C and B is a subtype of D, then checking subtyping is
undecidable.
In fashion terms: operator (-) is contravariant in its first argument and
covariant in its second.
;)
2011/3/16 Brandon Moore
Concerning this exercise, would it be simply possible to take the most of
lazy evaluation and build a graph?
A node would be:
Node a = Node { data:: a,
parents :: [Node a],
children :: [Node a] }
Then, whichever node you are on, you can still directly find its
Hello,
A question recently popped into my mind: does lazy evaluation reduce the
need to proper tail-recursion?
I mean, for instance :
fmap f [] = []
fmap f (x:xs) = f x : fmap f xs
Here fmap is not tail-recursive, but thanks to the fact that operator (:) is
lazy, I think that it may still run
daniel.is.fisc...@googlemail.com
On Wednesday 16 March 2011 18:31:00, Yves Parès wrote:
Hello,
A question recently popped into my mind: does lazy evaluation reduce the
need to proper tail-recursion?
I mean, for instance :
fmap f [] = []
fmap f (x:xs) = f x : fmap f xs
Here fmap
.
Can a type signature give you a hint about whether a function evaluates
some/all of its arguments (i.e. is strict/partially strict/lazy), or do you
have to look at the implementation to know?
2011/3/16 Daniel Fischer daniel.is.fisc...@googlemail.com
On Wednesday 16 March 2011 20:02:54, Yves
If you have only one alternative, then you can simply do:
Opt1 - someIO
E.g., if you are _sure_ that foo returns always a 'Just' within a monad you
can perfectly do :
Just x - foo
2011/3/14 tsuraan tsur...@gmail.com
In my code, I'm doing this quite a lot:
x - someIO
case x of
Opt1 -
init = mfix $ \ref -
newIORef $ do
writeIORef ref (return 0)
return init
2011/3/10 Edward Kmett ekm...@gmail.com
On Wed, Mar 9, 2011 at 6:21 PM, Yves Parès limestr...@gmail.com wrote:
Well, I want to hide the fact that I'm using ST, so if I can hide the
existential type 's
Why has the operator (.) troubles with a type like (forall s. ST s a)?
Why can't it match the type 'b' in (.) definition?
2011/3/10 Daniel Fischer daniel.is.fisc...@googlemail.com
On Thursday 10 March 2011 14:18:24, Anakim Border wrote:
Dear list,
I have the following (simplified) piece
Hello,
I am trying to make a monad that uses ST internally.
But even when reducing this to the simplest case I'm still cramped by the
's' phantom type :
{-# LANGUAGE Rank2Types #-}
newtype MyST a = MyST (forall s. ST s a)
-- ^ I cannot use deriving (Monad) through GeneralizedNewtypeDeriving
Thanks! It works this way.
I often forget the dangers of point-free notation...
2011/3/9 Jake McArthur jake.mcart...@gmail.com
Try `return x = MyST (return x)`. It's (.) that throws it off.
- Jake
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Haskell-Cafe mailing list
...@henning-thielemann.de
On Wed, 9 Mar 2011, Yves Parès wrote:
Hello,
I am trying to make a monad that uses ST internally.
But even when reducing this to the simplest case I'm still cramped by the
's' phantom
type :
{-# LANGUAGE Rank2Types #-}
newtype MyST a = MyST (forall s. ST s a)
-- ^ I
It evokes me Python's ctypes module.
Nice job ! I think It will be useful.
2011/3/6 Remi Turk rt...@science.uva.nl
I am happy to finally announce cinvoke 0.1, a binding to the
C library cinvoke[1], allowing functions to be loaded and called
whose names and types are not known before
Hello,
For testing purposes, I am trying to make an overlay to IO which carries a
phantom type to ensure a context.
I define contexts using empty type classes :
class CtxFoo c
class CtxBar c
The overlay :
newtype MyIO c a = MyIO (IO a)
Then I define some methods that run only a specific
On 5 March 2011 10:45, Yves Parès limestr...@gmail.com wrote:
Hello,
For testing purposes, I am trying to make an overlay to IO which carries
a
phantom type to ensure a context.
I define contexts using empty type classes :
class CtxFoo c
class CtxBar c
The overlay :
newtype
Foo Foo = True
type instance Ctx Bar Bar = True
runFoo :: MyIO Foo a - IO a
runBar :: MyIO Bar a - IO a
fooCtxAction :: (Ctx Foo c) ~ True = MyIO c ()
bothCtxAction :: (Ctx Foo c `Or` Ctx Bar c) ~ True = MyIO c ()
allCtxAction :: MyIO c ()
2011/3/5 Yves Parès limestr...@gmail.com
But I don't
Thanks for your proposal.
It is not clear if the class constraint is really needed.
Well 'IM' means 'ImplementationMonad', so it wouldn't make much sense if an
IM of an implementation wasn't also a monad. And since IM is the central
monad of the library, a lot of functions will use IM.
The
Hello,
I'm working on a library which aims to be a generic interface for 2D
rendering. To do that, one of my goals is to enable each implementation of
this interface to run in its own monad (most of the time an overlay to IO),
thus giving me the following class
class (Monad (IM i x)) = Impl i x
Thank you !
Is what I'm trying to do a common technique to type-ensure contexts or are
there simpler methods?
2011/3/2 Max Bolingbroke batterseapo...@hotmail.com
On 2 March 2011 09:11, Yves Parès limestr...@gmail.com wrote:
class (forall x. Monad (IM i x)) = Impl i where
data IM i
Okay thanks I got the difference between both.
The 'exists' syntax seems very useful. Is it planned to be added to GHC in a
near future?
2011/2/28 Heinrich Apfelmus apfel...@quantentunnel.de
Yves Parès wrote:
takeC :: Int - Compoz a b - (exists c. Compoz a c)
dropC :: Int - Compoz a b
takeC :: Int - Compoz a b - (exists c. Compoz a c)
dropC :: Int - Compoz a b - (exists c. Compoz c b)
What does 'exists' means? To create a rank-2 type can't you use:
takeC :: Int - Compoz a b - (forall c. Compoz a c)
??
2011/2/28 Heinrich Apfelmus apfel...@quantentunnel.de
Yitzchak Gale
://hackage.haskell.org/packages/archive/base/4.3.0.0/doc/html/Control-Applicative.html
2011/2/24 Yves Parès limestr...@gmail.com
I have the same problem with instances of Functor.
For instance when I import Control.Applicative, to get the instance
Functor ((-) a) I also have to import
I tried reinstalling GHC 7.0.1 from scratch, the issue remains...
2011/2/26 Daniel Fischer daniel.is.fisc...@googlemail.com
On Saturday 26 February 2011 12:54:02, Yves Parès wrote:
When I look at the documentation of Control.Monad.Error [1] or
Control.Applicative [2] it is not said
be that the same
memory can be assigned to another object by new operator, but it doesn't
get cleared or invalidated in any way.
Seems to me, Haskell works in the same way.
On 26 Feb 2011, at 13:59, Yves Parès wrote:
Hello,
I'm trying to use a C++ class in Haskell through C exports.
It works
I have the same problem with instances of Functor.
For instance when I import Control.Applicative, to get the instance
Functor ((-) a) I also have to import Control.Monad.Instances.
2011/2/23 Daniel Fischer daniel.is.fisc...@googlemail.com:
On Wednesday 23 February 2011 14:14:46, Yves Parès
I am using mtl-2. Importing Control.Monad.Error doesn't work, I have
to explicitly import Control.Monad.Instances.
2011/2/22 Daniel Fischer daniel.is.fisc...@googlemail.com:
On Tuesday 22 February 2011 23:07:05, Yves Parès wrote:
Hello,
When importing Control.Monad.Error, it shows me
The latest, I think :
GHC 7.0.1,
mtl-2.0.1.0,
base-4.3.0.0
2011/2/23 Daniel Fischer daniel.is.fisc...@googlemail.com:
On Wednesday 23 February 2011 09:58:56, Yves Parès wrote:
I am using mtl-2. Importing Control.Monad.Error doesn't work, I have
to explicitly import Control.Monad.Instances
Concerning game development in Haskell, I would be most interested in
an article explaining one (or several) game architectures in Haskell,
i.e. how do you design the high layers of your game to take the most
of Haskell features : threads, monads, type families etc.
I don't know if such a paper
Hello,
When importing Control.Monad.Error, it shows me that (Either e) is an
instance of MonadFix, but not an instance of Monad.
Isn't there a problem?
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Haskell-Cafe@haskell.org
I noticed the same issue under ubuntu when feeding my program (i.e. on the
command line) file names with special characters (my locale is fr_FR.UTF-8).
I discovered I had to use Codec.Binary.String.UTF8.decodeString. I didn't
know it was only for Unix.
2011/2/11 Joey Hess j...@kitenet.net
I've
I had a similar experience under Windows. Never really got to find out
why it happened. You might try adding a short threadDelay call in your
main loop and see what happens; I think it helped back then.
Wow... it's even worse. Even with a threadDelay of 1ms the FPS drop down to
a chaotic 20~30.
I
none of the examples use. But there isn't no known
problem with Param?
(Even if it's much more likely it comes from my code...)
2010/12/23 Yves Parès limestr...@gmail.com
Thanks for your answers. In fact I tried to use Simple with a clock signal
and it's painful to pass it wherever you need
Thanks for your answers. In fact I tried to use Simple with a clock signal
and it's painful to pass it wherever you need it. Param is much more
practical.
I like Elerea, I tried Reactive and Yampa, and I found them (especially
Yampa) heavy and not very practical.
The fact that Elerea is
Patai, I read your paper on Elerea. It wasn't easy :), but I think I got the
picture.
So I would have 2 questions :
I made a simple function which turns an infinite list into a signal :
fromList :: [a] - SignalGen (Signal a)
fromList xs =
stateful xs tail = memo . fmap head
1) It does what I
/raw/master/docs/works09paper.pdf
That describes a simple project that I think is similar to what you are
looking at doing. The code is in that github repository as well, a couple
directories up from the paper.
https://github.com/mjsottile/hsworkflow/
-m
On Dec 15, 2010, at 5:52 AM, Yves
Okay, I started to experiment things, and I came to some remarks:
First, I cannot use bare lists, because of the way their Applicative
instance is declared.
I have to use the newtype ZipList (in Control.Applicative).
So I have roughly this :
import Control.Applicative
newtype AgentSig a =
Hello Café,
I was wondering if using infinite lists was a viable and efficient solution
in haskell programs (I mean not simple prototypes) :
I was considering using them to model agents in a hierarchical multi-agent
application for school.
A list would representate the state of an agent at a step
-- tells
it was too good too be true ^^.
2010/12/15 Brent Yorgey byor...@seas.upenn.edu
On Wed, Dec 15, 2010 at 02:52:11PM +0100, Yves Parès wrote:
Hello Café,
So is it viable or would the use of multiple infinite lists kill the
performances?
Sounds perfectly reasonable to me. I don't
if one day you decide you need an agent that generates random numbers
I could say that my agents now run in a certain monad, I just would have to
transform my basic agents to :
agent1 = liftM . fmap (*2)
(or even agen1 = fmap . fmap (*2), however it is less readable IMO)
Thanks for your
I think this idea is a stairway to duck typing.
I exagerate, of course, but here is my point:
It shouldn't be difficult to make a class:
class HasName a where
name :: a - String
The problem is when declaring Foo and Bar instances of HasName, since you
have to copy code :
data Foo = Foo String
Brown nc...@kent.ac.uk
On 10/11/10 12:36, Yves Parès wrote:
I think this idea is a stairway to duck typing.
I exagerate, of course, but here is my point:
It shouldn't be difficult to make a class:
class HasName a where
name :: a - String
For accessing parts of data structures that have
Yes, I saw this offer.
Very, very interesting, but the duration of the internship wasn't specified.
By summer, I thought you meant July/August, didn't you? But we are looking
for a 6-month internship.
2010/11/8 Lee Pike leep...@gmail.com
Hi,
On a (possibly-related) note: Galois, Inc. and the
Nope, the page is outdated.
Gamr7 doesn't use Haskell currently. They used it before, but now Haskell is
sort of in standby. Currently they mostly use Python and C/C++.
I don't work here, I know it since I have applied for this intership
proposal (I'm french too) and been accepted.
2010/11/6 Vo
be some company or university in Europe that could offer
such an intership.
2010/11/6 Yves Parès limestr...@gmail.com
Nope, the page is outdated.
Gamr7 doesn't use Haskell currently. They used it before, but now Haskell
is sort of in standby. Currently they mostly use Python and C/C++.
I don't
Nice.
It is true that Python picked up some elements of Haskell, but now both
languages are mature enough so that features can go both ways.
It's called The *Ultimate* Computer Language Guide, and it's on the
internets, so it must be correct, right?
Wooow, it's barely 9 a.m. in France, it's
There are other ways of adding Haskell as a scripting language - bundling
ghc is not necessary.
Even the program which is to run the scripts is compiled with GHC?
I am interested to know how you do that.
2010/11/4 Malcolm Wallace malcolm.wall...@me.com
ehm. I missed something and ghc api is
I understand your point Ryan, but in that case, why didn't the error occur
when Resource and ResourceId were separated classes?
BTW, I assume for your Int instance of Resource, you meant:
instance Resource Int where
type IdOf *Int* = Int
type LocOf *Int* = String
type CfgOf *Int* = ()
Or maybe Lua?
There is already a Lua binding on Hackage.
I've been advised to use it when I was also looking for a scripting language
(and disadvised to use Scheme).
2010/11/2 Permjacov Evgeniy permea...@gmail.com
Let us think, that we need some scripting language for our pure haskell
project
Because he would have either to recompile the whole program or to use things
like hint, both implying that GHC must be installed on the user side (600Mo+
for GHC 6.12.3)
2010/11/2 Lennart Augustsson lenn...@augustsson.net
I don't understand. Why don't you use Haskell as the scripting
()) = eval rscs
-- -- -- Other cases yet to come...
greetings,
Sjoerd
On Nov 1, 2010, at 1:53 AM, Yves Parès wrote:
Hello,
I'm trying to make a simple monad (built on operational's ProgramT) for
resource loading.
I have classes featuring type families :
{-# LANGUAGE
not be injective
In the second argument of `retrieveLoc', namely `id'
In the expression: retrieveLoc cfg id
In the definition of `loc': loc = retrieveLoc cfg id
Seems like the compiler still has a 'rsc1' type despite the scoped type
variable 'rsc'.
2010/11/1 Yves Parès limestr...@gmail.com
Hello,
I'm trying to make a simple monad (built on operational's ProgramT) for
resource loading.
I have classes featuring type families :
{-# LANGUAGE TypeFamilies, FlexibleContexts, GADTs #-}
-- | A ResourceId is something that identifies a resource.
-- It should be unique for one resource,
Hello,
I would like to recode in Haskell a piece of bash program that uses find.
The advantage of find is that it is quite easy to use and fast.
Is there a package that let us access to find-like functionnalities, with
similar performances? Or at least some C functions that could be used
through
Thanks, I will take a look at it.
2010/8/22 Erik Hesselink hessel...@gmail.com
I've used the FileManip package for this. It works fine for my
purposes. I have no idea what the performance is, though, beyond 'good
enough not to care at the moment'.
Erik
On Sun, Aug 22, 2010 at 17:32, Yves
Thanks for the HSH link, Magnus.
Concerning FileManip, it seems that I can't perform easily a
case-insensitive search (for instance with find, you just use -iname instead
of -name). Am I wrong?
2010/8/22 Magnus Therning mag...@therning.org
On 22/08/10 16:32, Yves Parès wrote:
Hello,
I
:
run $ find fooé
it says :
find: foo*\351*: No file or directory
So it is not the same encoding!
2010/8/22 Yves Parès limestr...@gmail.com
Thanks for the HSH link, Magnus.
Concerning FileManip, it seems that I can't perform easily a
case-insensitive search (for instance with find, you just
)
-- Forwarded message --
From: Yves Parès limestr...@gmail.com
Date: 2010/8/22
Subject: Re: [Haskell-cafe] Perform a research a la Unix 'find'
To: Magnus Therning mag...@therning.org
Cc: haskell-cafe@haskell.org
I looked at both, and I have encoding issues with both.
My locale
Mmh, I raised this question some months ago, I thought about Scheme and I've
been recommended to use Lua instead of Scheme (as far as I remember, the
author of a scheme implementation available on Hackage told it wasn't solid
enough).
I would add something: who will script for your application?
(??) is misleading, some may be tempted to write things like: func ?? 45 ??
x , forgetting that ?? is just a mere operator, not a syntactic convenience.
Unfortunately, Haskell doesn't provide Scala's underscore for partially
applied functions: func(56, _, foo, _)
I've found that I like Erlang's pattern matching for sorting through
different kinds of data payloads, but that I prefer to use typed data
channels per Limbo, Go, Plan 9's thread and messaging libraries etc. I've
often wanted an Erlang with static typing to get this capability.
Actually you are
In fact, I noticed Holumbus.
You say that With the help of this library it is possible to build
Erlang-Style mailboxes, but how would you solve the issue of static typing?
Besides, Holumbus depends on package 'unix', preventing it from being used
on non-unix platforms.
2010/7/26 Stefan Schmidt
Hello !
I've been studying Erlang and Scala, and I was wondering if someone has
already implemented an actors and message passing framework for concurrent
and distributed programs in Haskell.
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