On Fri, Dec 17, 2010 at 11:04 AM, michael rice nowg...@yahoo.com wrote:
I don't understand this error message. Haskell appears not to understand
that 1 is a Num.
Prelude :t 1
1 :: (Num t) = t
Prelude :t [1,2,3,4,5]
[1,2,3,4,5] :: (Num t) = [t]
Prelude
Michael
===
f
On 17/12/2010 12:59 AM, Gregg Reynolds wrote:
This is a little off-topic, since it isn't specifically about Haskell,
but since Haskell is the home of the monad tutorial it isn't
completely irrelevant. The monad tutorial genre is well-known; it's
often written somebody who has just learned the
On 17 December 2010 12:45, Larry Evans cppljev...@suddenlink.net wrote:
Am I doing something wrong or has somehow community.haskell.org been
hijacked somehow?
Er, it works for me. Maybe *your* DNS has been hijacked? I know lots
of Windows viruses play tricks like this...
Max
I think it is giving you the error because you the fmap in your code is
operating on the IO monad and not the List monad. In order to get it to
work, you can remove the IO layer with = as below:
f :: [Int] - IO [Int]
f lst = do return lst
main = do let lst = f [1,2,3,4,5]
lst = return
This is a bit tricky.
The type of 'f' is '[Int] - IO [Int]', which means that the type of 'lst'
is 'IO [Int]'.
So fmap (+1) tries to add one to the [Int] underneath the 'IO' type
constructor.
You can either use two 'fmap's, the first to lift up to IO and the second to
lift into the list, or you
Jacek Generowicz wrote:
# Imagine an activity which may be performed either by a computer, or
# by a human (alternatively, either locally, or remotely across a
# network). From Haskell's type system's perspective, these two will
# look completely different (most obviously, the human (or the
#
On 12/17/10 07:07, Daniel Fischer wrote:
On Friday 17 December 2010 13:45:38, Larry Evans wrote:
WARNING: I clicked on that link in my thunderbird news reader
and got a page which was something about registering domains.
It was nothing about Neil's slides.
I then tried directing my Firfox
You might like to read about free and reclaimable memory on Linux
systems. I recommend that you go
http://linuxdevcenter.com/pub/a/linux/2006/11/30/linux-out-of-memory.html
and run the C programs that are included in the article. Another good
way to learn about Linux memory is to Google with the
Hi Michael
The type of lst is IO [Int] and therefore fmap (+1) applies (+1) to
the hole lists of integers, and not to each member of the list. That is:
fmap (+1) lst =
fmap (+1) (return [1,2,3,4,5]) =
return ([1,2,3,4,5] + 1)
and you cannot say [1,2,3,4,5] + 1.
Does that make sense?
Maybe
On Fri, Dec 17, 2010 at 3:03 AM, Ketil Malde ke...@malde.org wrote:
So I still think the 80% rule is pretty good - it's simple, and
although it isn't optimal in all cases, it's conservative in that any
larger bound is almost certainly going to thrash.
Please test the 80% rule, and report the
I have the same problem.
-deech
On Fri, Dec 17, 2010 at 8:01 AM, Eugene Kirpichov ekirpic...@gmail.com wrote:
Hello.
For a couple of friends of mine, hackage.haskell.org happens to
resolve to something strange (parked domain), though haskell.org works
ok. This might be something to tell to
On Fri, Dec 17, 2010 at 05:01:45PM +0300,
Eugene Kirpichov ekirpic...@gmail.com wrote
a message of 82 lines which said:
For a couple of friends of mine, hackage.haskell.org happens to
resolve to something strange (parked domain), though haskell.org works
ok. This might be something to tell
Hello,
please read:
http://www.reddit.com/r/haskell/comments/encrv/whats_happened_to_haskellorg_did_someone_forget/c19guw1
Thanks,
Karel
On 12/17/10 03:19 PM, Stephane Bortzmeyer wrote:
On Fri, Dec 17, 2010 at 05:01:45PM +0300,
Eugene Kirpichovekirpic...@gmail.com wrote
a message of
I think someone failed to pay a bill for using the domain name haskell.org.
John
On Fri, Dec 17, 2010 at 12:05 PM, aditya siram aditya.si...@gmail.com wrote:
I have the same problem.
-deech
On Fri, Dec 17, 2010 at 8:01 AM, Eugene Kirpichov ekirpic...@gmail.com
wrote:
Hello.
For a
It's fixed now. Try www.haskell.org. Check out
http://www.reddit.com/r/haskell/comments/encrv/whats_happened_to_haskellorg_did_someone_forget/
for more discussion.
-deech
On Sat, Dec 18, 2010 at 9:12 AM, John D. Ramsdell ramsde...@gmail.com wrote:
I think someone failed to pay a bill for using
Karel Gardas karel.gar...@centrum.cz writes:
http://www.reddit.com/r/haskell/comments/encrv/whats_happened_to_haskellorg_did_someone_forget/c19guw1
Quoth dons:
| The domain name was seized by Network Solutions (it wasn't due to
| expire until this time next year). The confusion seems to be
I am seeing this from New York. Has the domain expired?
dmmb:~ tony$ dig haskell.org
; DiG 9.6.0-APPLE-P2 haskell.org
;; global options: +cmd
;; Got answer:
;; -HEADER- opcode: QUERY, status: NOERROR, id: 36391
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION
On Thu, Dec 16, 2010 at 4:13 AM, Simon Marlow marlo...@gmail.com wrote:
If your program has large memory requirements, you might also benefit from
parallel GC in the old generation: +RTS -N2 -qg1.l
Testing shows this advice did not help in my case. The program that
implements the undecidable
To make that a little clearer, here is code that uses two calls to fmap to
drill through two monadic layers:
f :: [Int] - IO [Int]
f lst = do return lst
main = do let lst = f [1,2,3,4,5]
fmap (fmap (+1)) lst
So the order of operations is :
1. The first fmap converts an IO [Int] to
Note to community. Design the syntax of a language to support auto
indenting. Don't make me repeatedly hit the tab key.
John
On Thu, Dec 16, 2010 at 8:48 PM, Scott Michel scooter@gmail.com wrote:
Disclaimer: I'm not looking to start a favorite IDE flame war, or resurrect
Emacs vs. VIM
I can confirm this.
If anyone has an immediate problem with this, you can use 8.8.8.8 (google's
DNS server) as your DNS server.
jor...@jordan-laptop:~$ nslookup hackage.haskell.org 8.8.8.8
Server: 8.8.8.8
Address: 8.8.8.8#53
Non-authoritative answer:
Name: hackage.haskell.org
Address:
For me only hackage.haskell.org works (resolves to 69.30.63.204),
www.haskell.org shows parked domain (209.62.105.19)
Pavel
On 17.12.2010, at 17:01, Eugene Kirpichov wrote:
Hello.
For a couple of friends of mine, hackage.haskell.org happens to
resolve to something strange (parked domain),
On Fri, Dec 17, 2010 at 9:04 AM, michael rice nowg...@yahoo.com wrote:
I don't understand this error message. Haskell appears not to understand
that 1 is a Num.
Prelude :t 1
1 :: (Num t) = t
Prelude :t [1,2,3,4,5]
[1,2,3,4,5] :: (Num t) = [t]
Prelude
Michael
===
f ::
See the thread on the Haskell reddit about it:
http://www.reddit.com/r/haskell/comments/encrv/whats_happened_to_haskellorg_did_someone_forget/
I hope it is resolved soon.
Regards,
Bas
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Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
Er, it works for me. Maybe *your* DNS has been hijacked? I know lots
of Windows viruses play tricks like this...
No, the DNS for haskell.org was down yesterday - if you try again
today (after the DNS caches have cleared) it will work.
Thanks, Neil
The haskell.org domain expired. It's being worked on.
On 17 December 2010 12:45, Larry Evans cppljev...@suddenlink.net wrote:
On 12/17/10 01:32, Max Bolingbroke wrote:
[snip]
I can't speak for your monad based approach, but you may be interested
in Neil Mitchell's Haskell DSL for build
Is there a ByteString or Text version of getDirectoryContents? I am writing
a program which scans a filesystem and it runs out of memory using Strings
for all the file names, and I would like to avoid the overhead of calling
ByteString.pack on the results of getDirectoryContents.
I don't mind if
Warning! Incredibly hacky Haskell coming up!
Here's some code that seems to do the near same thing as your Python.
Below it is some sample output. A couple of differences are that the
secret number should be between 1 and 10, and whenever the computer
tries guess it just picks a random number
Nice.
Do you think there is any reason we would not be able to / want to use
it with happstack ? I would love happstack-data to 'go away' and just
use some library from hackage which does the same thing.
- jeremy
On Dec 17, 2010, at 3:57 AM, Erik Hesselink wrote:
I've recently been
No, I don't think so. It uses some extensions, but happstack-data
already does, so that shouldn't be a problem. We don't have a
releasable library yet, but when we do, it will have a versioned
binary implementation, just like happstack-data does now. Perhaps even
binary compatible with it, though
The whois still says it is registered to Galois, Inc. Then, hopefully, it is
just a DNS problem.
Guys, if you that are responsible for managing haskell.org need a hand with
sysadmin tasks I volunteer to work. I don't have lots of spare time, but I
do have some. Just let me know.
Thanks,
On Fri,
Thanks you all for your links,
I will read this.
However, Brent, I fail to understand your implementation of Monad... I
understand the purpose, but not the algorithm.
2010/12/18 Matthew Sottile mjsott...@mac.com
Hi-
This may be of some interest:
Excerpts from Jacek Generowicz's message of Fri Dec 17 20:17:30 -0500 2010:
Imagine an activity which may be performed either by a computer, or
by a human (alternatively, either locally, or remotely across a
network). From Haskell's type system's perspective, these two will
look completely
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
On 17 December 2010 18:04, michael rice nowg...@yahoo.com wrote:
===
f :: [Int] - IO [Int]
f lst = do return lst
main = do let lst = f [1,2,3,4,5]
fmap (+1) lst
The problem is that you are applying fmap to a type IO a.
fmap (+1) (return [1,2,3])
But to achieve
On 17 Dec 2010, at 21:44, Christopher Done wrote:
On 17 December 2010 18:04, michael rice nowg...@yahoo.com wrote:
===
f :: [Int] - IO [Int]
f lst = do return lst
main = do let lst = f [1,2,3,4,5]
fmap (+1) lst
The problem is that you are applying fmap to
I am using Vista x64. I have Haskell platform installed (Latest
varsion -available for Windows, 2010.2.0.0, GHC 6.12.3).
When I am trying to run picnic.hs from How To Organize a Picnic on a
Computer tutorial. I get this:
C:\...runhaskell picnic.hs
picnic.hs:46:18:
Warning: accepting
I bet they did try to contact the owner. But when the contact email no
longer works nobody will get the messages.
On Sat, Dec 18, 2010 at 3:35 PM, Ketil Malde ke...@malde.org wrote:
Karel Gardas karel.gar...@centrum.cz writes:
I agree with the feeling that Haskell tutorials feel like they are
bottom-up. But I think there's a reason for this: In my experience, at
least, Haskell applications are built bottom-up.
Functional programming languages strive for composability. In Haskell
you have very clean, clear ways of
No problem. Haskell is a different animal than even other functional
languages in my experience, and it takes time to get used to the coolness in
the type system, the lazy evaluation, the point free style, functional
composition and all the other interesting techniques you now have at your
(Moved from hask...@haskell.org)
Hi Kenneth,
I'm sorry for the very late reply.
On Wed, 2010-12-08 at 10:01 +0100, Kenneth Hoste wrote:
Hi Jan,
On 11/29/2010 12:55 PM, Jan Snajder wrote:
Dear Haskellers,
I am pleased to announce the release of genprog-0.1, a genetic
programming
Hello Haskell-cafers,
I used to teach Haskell (and Clean!) at University level but haven't
touched Haskell in years and certainly never used it with a Mac. Now I
work in publishing and want to experiment with Haskell's web services
and see if I can help set up an open-source system for
Hello,
It looks like you are using GHC 6.10, which is now a pretty old
version of GHC. The latest version of the unix package on hackage
requires a more recent version of GHC. You could try to force an older
version of the unix library:
cabal install happstack-server --constraints
Just to clarify - I was the contact for Haskell.org but the email address was
no longer being forwarded. I had assumed I had been removed as the contact but
unfortunately only the technical contact had been changed. All was finally
resolved with the help of Yale, where they resurrected the
I don't know about the ld warning, but cabal-install can never know
which version of cabal-install is installed, because it doesn't track
executables - it only tracks and knows about libraries.
Right after the warning is the line:
Installing executable(s) in /Users/matthew/.cabal/bin
So it
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