The following module takes an inordinately long time to
compile in ghc[i] (5.04):
module Y2 where
-- define the Y combinator without using built in recursion
data Y2 t = Recur (Y2 t - (t - t) - t)
y f = y2 (Recur y2) f
where y2:: Y2 t - (t - t) - t
y2 (Recur y2') f = f (y2'
http://haskell.cs.yale.edu/ghc/docs/latest/html/users_guide/bugs.html
Regrettable, but documented.
Simon
| -Original Message-
| From: Jon Fairbairn [mailto:[EMAIL PROTECTED]
| Sent: 03 March 2003 11:40
| To: GHC bugs
| Subject: loop?
|
| The following module takes an inordinately long
I'm playing with the Network library (the recommended portable way?) and
have a surprising problem with a simple client/server example. As the same
program works fine on Solaris and Win2k, I suspect its a standard feature
and someone here with more network programming experience might be
able to
Did you remember to use 'withSocketsDo'? If you
did, it would help to see the code that's failing
for you (trivial or not.)
--sigbjorn
- Original Message -
From: Claus Reinke [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Monday, March 03, 2003 04:14
Subject: Network on Win98: failed -
Did you remember to use 'withSocketsDo'? If you
did, it would help to see the code that's failing
for you (trivial or not.)
Did. But you're right, of course, so here's the current code.
Claus
-- Server.hs
module Main where
import Network
import IO
import System
main = withSocketsDo $ do
Still looking for inspirations on this one. I'm not at all sure I interpret the chain
of indirections in the CVS sources correctly, but Network.Socket uses
throwErrnoIfMinus1Retry, which does indeed try to use errno to figure out
what went wrong. Is that redirected anywhere for windows?
Because,
Mike T. Machenry [EMAIL PROTECTED] writes:
I am having a problem. I recently desided I wanted a bunch function to return
float instead of Int. I changed their type and wrote a new function that
returned a float. I figured it'd be okay if all the others still returned
Int since it's trivial
| The reason, which is thoroughly explained in Simon Peyton-Jones'
| message, is that the given type signature is wrong: it should read
| f1 :: (exists b. (C Int b) = Int - b)
|
| Right. Simon pointed out that this is a pretty useless function, but
not
| entirely so, since the result of
Thanks a lot m8 but ghc says it can't the module IOExts when I try to
compile, any suggestion??? Do I just use normal writeFile method to create
the text file then??
Best Regards
Alex
- Original Message -
From: Glynn Clements [EMAIL PROTECTED]
To: Alexandre Weffort Thenorio [EMAIL
OK I fixed the IOExts not found problem (-package lang) but my problem now
is that I never worked with handles. How can I write the string to the file
and so on?? Where can I find more info on handle data types??
Best Regards
NooK
- Original Message -
From: Glynn Clements [EMAIL
Dear all, we want to access a (MySQL) data base,
running on a linux server, from a Haskell program.
We planned to use http://www.volker-wysk.de/mysql-hs/
but it depends on earlier versions of hdirect (0.17?) and ghc(-4?).
I built hdirect-0.19 (?) (from the ghc CVS) but the Foreign interfaces
seem
Folks
I am holding in my hands the first copy of the Haskell 98 Report to roll off the
presses at Cambridge University Press. It looks great. And it has a copyright
notice that says It is intended that this Report belong to the entire Haskell
community..., just as the online version does.
Have a look here:
http://haskell.cs.yale.edu/haskellDB/
___
Haskell mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/haskell
Johannes Waldmann [EMAIL PROTECTED] writes:
Dear all, we want to access a (MySQL) data base,
running on a linux server, from a Haskell program.
We planned to use http://www.volker-wysk.de/mysql-hs/
but it depends on earlier versions of hdirect (0.17?) and ghc(-4?).
I built hdirect-0.19 (?)
On 03 Mar 2003 13:57:06 +, Steffen Mazanek [EMAIL PROTECTED] wrote:
Dear all, we want to access a (MySQL) data base,
running on a linux server, from a Haskell program.
Have a look here:
http://haskell.cs.yale.edu/haskellDB/
A word of warning though from the author :-),
HaskellDB is somewhat
What User Interface Library would you recommend for use under Windows?
I tried FranTk but it crashes as soon as I run the display function (under
hugs)
and with ghc it won't even compile (I already tinkered with the makefiles,
so
finally I could make the package, but then the demos won't compile).
On Mon, 3 Mar 2003 16:21:22 +0100, [EMAIL PROTECTED] wrote:
What User Interface Library would you recommend for use under Windows?
Unfortunately, there is no official GUI library for Haskell yet (but many
people are working toward this goal at the haskell gui mailing list).
At the moment, the
On Mon, Mar 03, 2003 at 04:21:22PM +0100, [EMAIL PROTECTED] wrote:
What User Interface Library would you recommend for use under Windows?
I tried FranTk but it crashes as soon as I run the display function (under
hugs)
and with ghc it won't even compile (I already tinkered with the makefiles,
Thank does sound like a pain, but it's better than putting fromIntegral
all over my code. Why can't Haskell unify a an expected float with an
infered int? It seems that this would make life alot easier.
-mike
On Sun, Mar 02, 2003 at 11:28:00AM +, Jorge Adriano wrote:
Mike T. Machenry
Hello.
I do Literate Programming this way:
At first I define a Latex environment code as verbatim
e.g. so: \newenvironment{code}{\footnotesize\verbatim}{\endverbatim\normalsize}
This environment is understood by the Haskell compilers.
All my modules are own documents concluded in the main
| entirely so, since the result of it is not of type 'forall b. b', but
| rather of 'forall b. C Int b = b'. Thus, if the C class has a
function
| which takes a 'b' as an argument, then this value does have use.
I disagree. Can you give an example of its use?
I believe something
| The reason, which is thoroughly explained in Simon Peyton-Jones'
| message, is that the given type signature is wrong: it should read
| f1 :: (exists b. (C Int b) = Int - b)
Can you give an example of its use?
Yes, I can.
class (Show a, Show b) = C a b | a - b where
doit:: a -
Thanks a lot m8. I got it. I was supplying it with --make but not with -o.
Thanks again. I guess everything is fine now thanks to you guys.I wanna
learn more about catching errors but that comes later when I finish this
program.
Best Regards
Alex
- Original Message -
From: Nils Decker
Yo,
Steffen Mazanek wrote:
I do Literate Programming this way:
At first I define a Latex environment code as verbatim
e.g. so: \newenvironment{code}{\footnotesize\verbatim}{\endverbatim\normalsize}
When I ran into the same question some time ago I tried that,
but found that the \verbatim was
Hi, Shae
Also, HToolkit has working but not yet stable
support for both postgresql and
mysql. I haven't tried the mysql interface myself,
but I have tried the
postgresql code. It works, but it does explode if
you do something unexpected.
http://sourceforge.net/projects/htoolkit/
Can
The following is a more flexible alternative to overloading. We
essentially define a function on types and invoke it, seemingly at run
time. No Dynamics or unsafe computations are employed. We only need
existential types, multi-parameter classes and functional
dependencies. The code also shows
Hi,
Since I sent this to the haskell list in the first place,
I'd better let everyone know that it all worked out.
Hmm, there were no problems in simply doing so.
Ok, I've cut your example down a bit (just from a
minimalist tendency). The complete modified code is ...
Is there some way to reduce the cost of garbage collection over large persistent
datastructures without resorting to escaping to C to malloc memory outside the
heap?
The program I'm working is part database, which cannot discard information.
The net result is that I see figures like 82.9% of the
Matthew Donadio [EMAIL PROTECTED] writes:
Thank does sound like a pain, but it's better than putting fromIntegral
all over my code. Why can't Haskell unify a an expected float with an
infered int? It seems that this would make life alot easier.
Personally, I think that one of the things that
Cagdas Ozgenc [EMAIL PROTECTED] wrote:
Greetings,
Is identity function the only meaningful function one can write
without constraining the type variable using a typeclass? If not,
could you please give a counter-example?
Certainly you can write lots of ``meaningful function''s
Greetings,
1) How does one model out of memory condition in Haskell, perhaps
using a Maybe type?
Unfortuntely not since it would not be referentially transparent. It's
part of a more general issue of exceptions in pure code.
You can't have
calculateSomething :: X - Maybe Y
Such
I did not mean to include functions that take type constructors as
parameters (so lists are out of my discussion scope). I am only considering
functions that uses type variables that are not restricted by typeclasses.
There is const:
const :: a - b - a
const x _ = x
And of course a
Does this make the use of Monads doubtful? I mean it doesn't seem easy to
have a completely pure language, and the time one starts introducing few
impurities one also starts thinking why not include many others?
I suggest that you read this paper:
A semantics for imprecise exceptions,
I did not mean to include functions that take type constructors as
parameters (so lists are out of my discussion scope). I am only
considering
functions that uses type variables that are not restricted by
typeclasses.
There is const:
const :: a - b - a
const x _ = x
And of
On Monday, 2003-03-03, 10:00, CET, Cagdas Ozgenc wrote:
[...]
I did not mean to include functions that take type constructors as
parameters (so lists are out of my discussion scope). I am only considering
functions that uses type variables that are not restricted by typeclasses.
In this
My three eurocents.
I believe that the Author of the original query won't care more about
undefined stuff than most of us. He wants truly polymorphic functions,
of the type, say, a-b-a etc., without constraints.
The answer exists, although it is not always trivial to find interesting
Hello. I'm running into a problem with the Network module, which I suspect
is pretty easy to fix, but am not sure how to best do so.
The problem is that accept fails when the reverse DNS fails, with the
following error:
Fail: does not exist
Action: getHostByAddr
Reason: no such host entry
I'm
So, I'm having to calculate 'n choose k' an awful lot. At the moment I've got
this:
comb :: Integer - Integer - Integer
comb m 0 = 1
comb m n = (numerator(toRational (fact m) / toRational (fact n * fact (m-n
where fact is a memoized factorial function. It's not perfectly memoized,
I think you would get a big speed-up if you got rid of all the rational
stuff and just used:
comb m n = fact m `div` (fact n * fact (m-n))
If that doesn't speed it up enouch, you can of course cache fact m in your
computation and do something like:
sumbn n = sum [ bournoulli i * fm `div` (fn *
On Tuesday, March 4, 2003, at 10:26 AM, Damien R. Sullivan wrote:
So, I'm having to calculate 'n choose k' an awful lot. At the moment
I've got
this:
comb :: Integer - Integer - Integer
comb m 0 = 1
comb m n = (numerator(toRational (fact m) / toRational (fact n * fact
(m-n
where fact is
G'day all.
On Mon, Mar 03, 2003 at 04:59:21PM -0800, Hal Daume III wrote:
I think you would get a big speed-up if you got rid of all the rational
stuff and just used:
comb m n = fact m `div` (fact n * fact (m-n))
Or, even better, if you didn't multiply stuff that you're just going
to
I have no idea if the following is faster or not (I suspect not), but
it is certainly easier to read:
n `choose` k = (n `permute` k) `div` (fact k)
n `permute` k = product [(n-k+1) .. n]
fact n = product [1 .. n]
mike
--
mike castleman / [EMAIL PROTECTED] / http://mlcastle.net
aolim: mlcastle
On Tue, Mar 04, 2003 at 12:25:01PM +1100, Andrew J Bromage wrote:
Or, even better, if you didn't multiply stuff that you're just going
to divide out in the first place.
I had thought of that before, and used a simple
comb m n = product [m, m-1 .. m-n+1] / fact (m-n)
but the unmemoized product
On Mon, Mar 03, 2003 at 04:59:21PM -0800, Hal Daume III wrote:
comb m n = fact m `div` (fact n * fact (m-n))
This was the biggest help, 33 seconds instead of my original 43. fact is the
big consumer now, and I think cries out for being arrayed, especially as it
gets used a lot elsewhere too.
main =
do
args - System.getArgs
let (m, b) = (read (args!!0), read (args!!1))
let lim :: Int
lim = read (args!!2)
printstate = args!!3
time1 - getClockTime
let n = 2^b
let afact = array (0,n) ((0,1):[(i,i*afact!(i-1)) |
On Tue, Mar 04, 2003 at 03:06:13PM +1100, Bernard James POPE wrote:
Damien writes:
main =
do
args - System.getArgs
let (m, b) = (read (args!!0), read (args!!1))
let lim :: Int
lim = read (args!!2)
printstate = args!!3
Hi,
For the reason that I'm lazy and don't want to have to modify all my functions
which use afact, or call functions which use afact, and don't see why I should
have to -- they were able to call the 'fact' function as a global, and can
refer to a global 'afact' if I define it outside of main
On Mon, Mar 03, 2003 at 10:45:38PM -0600, Jon Cast wrote:
Never programmed in C++ much, eh?
Only for a few years, professionally.
In general, getting the ordering of initialization right in the general
case is a harder problem than you might think.
It's not something I'd be having trouble
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