Hello haskell-cafe,
now i'm reading Haskell' proposals and found that these two things
considered as different:
http://hackage.haskell.org/trac/haskell-prime/wiki/ExistentialQuantification
http://hackage.haskell.org/trac/haskell-prime/wiki/PolymorphicComponents
can you please explain me what is
As requested, I continue here the thread on the proposal for a web forum.
You will soon enough find out what I think of web forums. Let me
first show you what this mailing list looks like to me using software
of my choice:
! [ 192: Mark Carroll] [Haskell-cafe] Card trick
! [ 37:
[apologies to Bulat for the repeat posting]
On Thu, Sep 21, 2006 at 12:05:23PM +0400, Bulat Ziganshin wrote:
now i'm reading Haskell' proposals and found that these two things
considered as different:
http://hackage.haskell.org/trac/haskell-prime/wiki/ExistentialQuantification
Hello Bruno,
Thursday, September 21, 2006, 8:28:23 AM, you wrote:
First, how do I fix the identation of the if then else?
http://haskell.org/haskellwiki/IO_inside contains a lot of information
about using IO monad
Second, I want to test this function, without hitting the filesystem. In
C++
Hello George,
Thursday, September 21, 2006, 7:44:22 AM, you wrote:
sh :: String - String - IO String
sh cmd = \input -
do (stdin, stdout, _, pid) - runInteractiveCommand cmd
forkIO $ hPutStr stdin input hClose stdin
-- get exit status to prevent zombie
Hello Ross,
Thursday, September 21, 2006, 12:55:40 PM, you wrote:
data Ex = forall a. Num a = Ex a
and
data Po = Po (forall a. Num a = a)
Consider the types of the constructors:
Ex :: forall a. (Num a) = a - Ex
Po :: (forall a. (Num a) = a) - Po
sorry, Ross, can you give me a more
On Thu, 2006-09-21 at 04:55 -0400, Albert Lai wrote:
As requested, I continue here the thread on the proposal for a web forum.
You will soon enough find out what I think of web forums.
[snip]
I don't understand one thing: it looks like web-forums should exclude
mailing lists and vice
Hello Bullat,
now i'm reading Haskell' proposals and found that these two things
considered as different:
http://hackage.haskell.org/trac/haskell-prime/wiki/ExistentialQuantification
http://hackage.haskell.org/trac/haskell-prime/wiki/PolymorphicComponents
can you please explain me
On 9/21/06, Gour [EMAIL PROTECTED] wrote:
So, why the two cannot co-exist and let users decide which one to use?
Gentoo community is nice example of it.
I was just about to ask the same thing. Clearly, some prefer email and
some prefer web forums. This is undoubtably true of new Haskell users
I have only recently started accessing some web fora, but I've noticed
that some of those powered by phpBB are vulnerable to spamming,
whereas the news groups seem to be less so. For example, the
python-forum has nearly lost it's General forum to spammers. Maybe
the experts know better engines,
Hallo,
On 9/21/06, Bill Wood [EMAIL PROTECTED] wrote:
I have only recently started accessing some web fora, but I've noticed
that some of those powered by phpBB are vulnerable to spamming,
whereas the news groups seem to be less so. For example, the
python-forum has nearly lost it's General
Kurt Hutchinson wrote:
Let those interested in a web forum set one
up and run it. Those interested in email can ignore the web forum.
My concern about introducing a web forum would be that it is yet
another place I have to search every time I need information (besides
the haskell report,
Hello Bullat,
also, ghc66 adds impredicative polymorphism. how it differs from
unqualified existentials?
I have not tried ghc66, but I think one of the things you should be able to
do and that
is perhaps helpful for understanding existencial is:
myList :: [forall a . Num a = a]
On Thu, 21 Sep 2006 01:52:38 -0300, Donald Bruce Stewart
[EMAIL PROTECTED] wrote:
First, how do I fix the identation of the if then else?
getList = find 5
where find 0 = return []
find n = do
ch - getChar
if ch `elem` ['a'..'e']
then do
On Thu, 21 Sep 2006 11:20:33 -0300, Henning Thielemann
[EMAIL PROTECTED] wrote:
On Thu, 21 Sep 2006, Bruno Martínez wrote:
getList :: IO [Char]
getList = take5 `fmap` getContents -- a thin IO skin
take5 :: [Char] - [Char]
take5 = take 5 . filter (`elem` ['a'..'e']) --
On Thu, 21 Sep 2006 05:30:34 -0300, Bulat Ziganshin
[EMAIL PROTECTED] wrote:
Hello Bruno,
Thursday, September 21, 2006, 8:28:23 AM, you wrote:
First, how do I fix the identation of the if then else?
http://haskell.org/haskellwiki/IO_inside contains a lot of information
about using IO monad
On 21/09/06, Misha Aizatulin [EMAIL PROTECTED] wrote:
My concern about introducing a web forum would be that it is yet
another place I have to search every time I need information (besides
the haskell report, compiler docs and tracker, 2 wikis and the mailing
lists :)
So let's have a single
Consider the following:
data SimpExist a = SimpExist (forall x . x - a)
f :: SimpExist Bool
f = SimpExist (const True)
g = SimpExist id
What is the type of g? In a similar example, GHC tells me it is of
type SimpExist c. Yet, I can't unify it with any other SimpExist c'.
It seems to me that
On 20/09/06, John Ky [EMAIL PROTECTED] wrote:
So Monads don't actually eliminate laziness?
Monads and laziness are completely orthagonal issues; they have
nothing to do with one another. I think you're getting confused with
purity. Monads can be used to encapsulate effects, to allow you to
On 9/21/06, Misha Aizatulin [EMAIL PROTECTED] wrote:
My concern about introducing a web forum would be that it is yet
another place I have to search every time I need information (besides
the haskell report, compiler docs and tracker, 2 wikis and the mailing
lists :)
That probably speaks to
Hello,
Consider the following:
data SimpExist a = SimpExist (forall x . x - a)
f :: SimpExist Bool
f = SimpExist (const True)
g = SimpExist id
What is the type of g? In a similar example, GHC tells me it is of
type SimpExist c. Yet, I can't unify it with any other SimpExist c'.
Have you tried
Moved to haskell-cafe from haskell-general.
On 2006-09-20, Niklas Broberg [EMAIL PROTECTED] wrote:
On 9/20/06, Aaron Denney [EMAIL PROTECTED] wrote:
And I disagree with you. Web forums are usenet reinvented poorly.
It's impossible to keep track of what's new, threading is either poor or
Bruno Martínez wrote:
On Thu, 21 Sep 2006 01:52:38 -0300, Donald Bruce Stewart
[EMAIL PROTECTED] wrote:
First, how do I fix the identation of the if then else?
getList = find 5
where find 0 = return []
find n = do
ch - getChar
if ch `elem` ['a'..'e']
I'll just add myself onto the list of webforum haters.
I find gmane over a news reader much more comfortable that any webforums I
have used.
Perhaps gmane can be used over a web interface?
Then those that want to use a web forum have one, and I can continue to use
my news reader.
When I want
Bulat Ziganshin wrote:
Hello Ross,
Thursday, September 21, 2006, 12:55:40 PM, you wrote:
data Ex = forall a. Num a = Ex a
and
data Po = Po (forall a. Num a = a)
Consider the types of the constructors:
Ex :: forall a. (Num a) = a - Ex
Po :: (forall a. (Num a) = a) - Po
sorry,
On 9/21/06, Rene de Visser [EMAIL PROTECTED] wrote:
I'll just add myself onto the list of webforum haters.
I find gmane over a news reader much more comfortable that any webforums I
have used.
Just to be clear. Is it worth debating which is better? Some people
prefer one over the other,
On 21/09/06, Sebastian Sylvan [EMAIL PROTECTED] wrote:
I do think we should try to do better than the usual suspects that are
available though. Maybe even write something in Haskell?
This sounds like a good test of maturity for Haskell web platforms.
I'd love to be involved in a collaboration
Hello Bruno,
Thursday, September 21, 2006, 6:16:49 PM, you wrote:
Second, I want to test this function, without hitting the filesystem.
In
C++ I would use a istringstream. I couldn't find a function that
returns
a Handle from a String.
http://haskell.org/haskellwiki/Library/Streams
On 21/09/06, Benjamin Franksen [EMAIL PROTECTED] wrote:
Emacs is evil!
I'll ignore the throwaway flaimbait there ;)
It also inserts random tab characters into your code just to save a few
space bytes. Tends to completely trash indentation e.g. when pasting code
into mails etc.
Not once
On Thu, 21 Sep 2006, George Brewster wrote:
I'm just tried writing a function to allow convenient embedding of shell
commands, but I'm running into behavior I don't really understand
somewhere at the intersection of lazy evaluation, IO, and threading.
You may also find some unwelcome
On 9/21/06, Bruno Oliveira [EMAIL PROTECTED] wrote:
Have you tried to type check this example (the g)?
No. Please excuse me, as I wasn't by my GHC at the time. Let's try:
data SimpExist a = Base a
| SimpExist (SimpExist (forall x . x - a))
g :: SimpExist (forall a . a - a)
g =
Hi,
I think the following might help a little in understanding the
monomorphic restriction (which I don't fully understand myself). I'm a
bit of a newbie so apologies in advance if I've made a mistake or if my
description isn't as useful to others as it seems to me. I've been
following a
When I look at the generated core, I see that both h and
same = Base undefined
have the same type:
%forall a . main:Fonly.SimpExist a
I'm using GHC 6.5.20060819.
If this is a bug, I actually find it kind of useful, for reasons I can
elaborate later.
Jim
Donn Cave wrote:
On Thu, 21 Sep 2006, George Brewster wrote:
I'm just tried writing a function to allow convenient embedding of shell
commands, but I'm running into behavior I don't really understand
somewhere at the intersection of lazy evaluation, IO, and threading.
You may also find
On Thu, 21 Sep 2006 15:12:07 -0300, Benjamin Franksen
[EMAIL PROTECTED] wrote:
OK. Thanks. I didn't find that one because it's not offered as an
identation option in emacs haskell mode.
Emacs is evil!
I'm open to alternatives. I use Windows, so went out of the way to have
emacs.
On Thu, 21 Sep 2006, George Brewster wrote:
...
Yup, I'm on linux. My goal is to have a function which gives me a lazy
string which is the output of a shell command, and takes a string as
input. In particular, I'd like the shell command to behave lazily (read
only as much input as is
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