[Redirecting to haskell-cafe]
Try
http://www.haskell.org/ghc/docs/latest/html/users_guide/flag-reference.html#id2959068
With -Wall I get
bash-3.2$ ghc -c -Wall Foo.hs
Foo.hs:3:0:
Warning: Definition but no type signature for `func'
Inferred type: func :: forall t t1. (Num t1)
-Ursprüngliche Nachricht-
Von: adamtheturtle kill2thr...@hotmail.com
Gesendet: 22.03.2010 04:52:19
An: haskell-cafe@haskell.org
Betreff: [Haskell-cafe] Re: Occurs check error, help!
Ivan Miljenovic ivan.miljenovic [ gmail.com writes:
Since my answer before to your question obviously
Ozgur Akgun wrote:
Is there any way to limit a functions type, not by a data type but by a
group of constructors of a data type? If not, what would be the *right*
thing to do to achieve this level of type safety?
data DT1 = X | Y | Z
data DT2 = A | B | C | D
func1 :: DT1 - DT2 -- instead of
Dear all, there is this neat one-line BFS implementation
bfs :: Eq a
= ( a - [a] ) - a - [a]
bfs next start =
let xs = nub $ start : ( xs = next )
in xs
but it has a problem: it only works for infinite graphs. This is fine:
take 20 $ bfs ( \ x - [2*x, x+1] ) 1
but this is not:
On Mon, Mar 22, 2010 at 11:02:32AM +0100, Johannes Waldmann wrote:
Dear all, there is this neat one-line BFS implementation
bfs :: Eq a
= ( a - [a] ) - a - [a]
bfs next start =
let xs = nub $ start : ( xs = next )
in xs
but it has a problem: it only works for infinite
Nice! - Where's the 'nub'?
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Dreading the end of ZuriHac? Wish the Haskellian camaraderie could
continue?
Well, if you're able to make your way to Sydney, Australia between the
16th and 18th of July, then AusHac2010 is for _you_! It will be held
at the School of Computer Science and Engineering at the University of
New
On Mon, Mar 22, 2010 at 10:30:32AM +, Johannes Waldmann wrote:
Nice! - Where's the 'nub'?
A bit longer:
bfs :: Eq a = (a - [a]) - a - [a]
bfs f s = concat $ takeWhile (not . null) $ map snd $ iterate step ([], [s])
where step (seen, xs) = let seen' = xs++seen in (seen', nub $ [y | x - xs,
A bit closer to the original:
bfs :: Eq a = (a - [a]) - a - [a]
bfs f s = concat $ takeWhile (not . null) levels
where levels = foldr trim [] $ [s] : map (nub . (= f)) levels
trim xs xss = xs : map (\\ xs) xss
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Ross Paterson wrote:
On Mon, Mar 22, 2010 at 10:30:32AM +, Johannes Waldmann wrote:
Nice! - Where's the 'nub'?
A bit longer:
bfs :: Eq a = (a - [a]) - a - [a]
bfs f s = concat $ takeWhile (not . null) $ map snd $ iterate step ([], [s])
where step (seen, xs) = let seen' = xs++seen
Hello, I was recentyl playing with Haskell (GHC that is) IO and text
processing.
Bytestrings and Lazy Bytestrings allow for fast and memory eficient
string (well, bytestring) handling, yet a lot of libraries do not
support them (yet)
Given the incredibly inneficient memory representation of
Johann Höchtl johann.hoec...@gmail.com writes:
Bytestrings and Lazy Bytestrings allow for fast and memory eficient
string (well, bytestring) handling, yet a lot of libraries do not
support them (yet)
WHat do you mean? A lot of libraries need to use String because it's
easier to deal with and
On Mon, Mar 22, 2010 at 1:16 PM, Johann Höchtl johann.hoec...@gmail.com wrote:
My question or discussion point: Why not depreciate [Char] altogether
and favour of lazy Bytestrings?
A sequence of bytes is not the same thing as a sequence of Unicode
code points. If you want to replace String by
On 23 March 2010 00:10, Johan Tibell johan.tib...@gmail.com wrote:
A sequence of bytes is not the same thing as a sequence of Unicode
code points. If you want to replace String by something more efficient
have a look at Data.Text.
Though Data.Text still has the disadvantage of not being as
On the page:
http://hackage.haskell.org/platform/
I am told that the platform includes ghc-6.10.4, but if I click there on the
Haskell:batteries included link to get to the page:
http://hackage.haskell.org/platform/contents.html
its states there that I get 6.12.1?
Doaitse
doaitse:
On the page:
http://hackage.haskell.org/platform/
I am told that the platform includes ghc-6.10.4, but if I click there
on the Haskell:batteries included link to get to the page:
http://hackage.haskell.org/platform/contents.html
its states there that I get 6.12.1?
The
It seems that I am being served old pages by my web browser from the cache on
my machine. By reloading the platform page, I suddenly am asked what system I
do have, from weher I am referred to the 6.12 version of the platform,
Doaitse
On 22 mrt 2010, at 14:25, Don Stewart wrote:
doaitse:
doaitse:
It seems that I am being served old pages by my web browser from the
cache on my machine. By reloading the platform page, I suddenly am
asked what system I do have, from weher I am referred to the 6.12
version of the platform,
Great!
___
There are three new packages on Hackage:
- monad-parallel 0.5
(http://hackage.haskell.org/package/monad-parallel)
- monad-coroutine 0.5
(http://hackage.haskell.org/package/monad-coroutine)
- Streaming Component Combinators 0.5
(http://hackage.haskell.org/package/scc)
The
Hi everyone,
is there a mailing list for CUFP-lers?
I have some questions that are related to commercial software
development (in Haskell) which I don't think fit well on this list.
Günther
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On Mon, Mar 22, 2010 at 6:10 AM, Johan Tibell johan.tib...@gmail.comwrote:
On Mon, Mar 22, 2010 at 1:16 PM, Johann Höchtl johann.hoec...@gmail.com
wrote:
My question or discussion point: Why not depreciate [Char] altogether
and favour of lazy Bytestrings?
A sequence of bytes is not the
Hello All
Modern functional programming languages give you algebraic data types
that are mighty convenient for programming with syntax trees. However,
I'm working in a domain (music typesetting) where modelling syntax
with trees can be problematic and I'm wondering whether I should work
at a
David Leimbach wrote:
On Mon, Mar 22, 2010 at 6:10 AM, Johan Tibell johan.tib...@gmail.com
mailto:johan.tib...@gmail.com wrote:
On Mon, Mar 22, 2010 at 1:16 PM, Johann Höchtl
johann.hoec...@gmail.com mailto:johann.hoec...@gmail.com wrote:
My question or discussion point: Why
wren ng thornton w...@freegeek.org writes:
I'm still on 10.5.8. I don't have cabal-install installed yet, but I just
installed GHC-6.12.1/HP-2010.1.0.0. I can verify that ghci works fine so
far. I'll check out cabal-install in the next couple days.
If there is an issue here it'd be with the
Bertram Felgenhauer wrote:
or
bfs next start = lefts . takeWhile (not . null)
I copied the wrong version. This should be
bfs next start = rights . concat . takeWhile (not . null)
-- rest unchanged
. unfoldr (Just . span (either (const False) (const True)) . tail)
Live from (post-) Zurihac, I'm pleased to announce the 2010.1.0.0 (beta branch)
release of the Haskell Platform, supporting GHC 6.12.
http://hackage.haskell.org/platform/
The Haskell Platform is a comprehensive, robust development environment for
programming in Haskell. For new users the
I wonder if this would be a place to add a function returning the pair
of the read and write capabilities (for the lack of a better word) of a
value.
something like:
rwPair:: v α - (ReadOnly v α , WriteOnly v α)
rwPair a = (readOnly a, writeOnly a)
sorry for the lame name,
I'm working in a domain (music typesetting) where modelling syntax
with trees can be problematic and I'm wondering whether I should
work at a lower level - essentially a list / stream of lexemes and
some notion of a context stack for processing, tracking when I'm
inside a tuplet and the
Hi Malcolm
Thanks - particularly I don't want to go to an AST because its I'm
finding it too convoluted 'shape wise' - processing beam groups inside
tuplets etc. is a nightmare - music representations have had at least
eight centuries of ad hoc extension.
I know Norman Ramsey and colleagues
Thank you all very much for the pointers.
Best,
On 22 March 2010 09:32, Gleb Alexeyev gleb.alex...@gmail.com wrote:
Ozgur Akgun wrote:
Is there any way to limit a functions type, not by a data type but by a
group of constructors of a data type? If not, what would be the *right*
thing to do
Hackage seems to be down again.
$ cabal update
Downloading package list from server
'http://hackage.haskell.org/packages/archive'
^Ccabal: interrupted
$ ping -c3 hackage.haskell.org
PING abbot.galois.com (69.30.63.204) 56(84) bytes of data.
--- abbot.galois.com ping statistics ---
3 packets
Turn on OverloadedStrings and you can pattern match on any type you
like that is in the IsString class.
Which means that Data.Text can use string literals just like regular
strings (but you can't use Char literals in the match).
On Mon, Mar 22, 2010 at 1:15 PM, Ivan Miljenovic
We're watching *massive* traffic right now due to HP release.
It's not down, just very very busy.
For fun, here's a map of who's downloading Haskell:
http://imgur.com/flwPF.png
74 countries in 12 hours, and counting.
- Don
dougal:
Hackage seems to be down again.
$ cabal update
I'd love to see that map normalised by the population of the country – would be
interesting to see where Haskell is popular.
Bob
On 22 Mar 2010, at 16:22, Don Stewart wrote:
We're watching *massive* traffic right now due to HP release.
It's not down, just very very busy.
For fun, here's a
Hi everybody,
At ZuriHac I released data-category. It is an implementation of several
category-theoretical constructions.
I started this library to learn about both category theory and type level
programming, so I wanted to implement the CT concepts as directly as possible.
This in contrast
Hi Cliff,
here is a link which might interest you
http://en.wikipedia.org/wiki/Zoroastrianism
Love
Günther
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Hmm. What are benefits of data-category over category-extras?
Regards
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Mainly that category-extras doesn't have restricted categories, so most of the
categories in data-category cannot be defined with category-extras. This also
means that in category-extras many constructions are built from the ground up,
instead of being built with a few basic building blocks,
BTW, I started to try the macports method (thinking that maybe
building on my machine would resolve the linker problem), but the
package up there seems to be the old one:
$ port info haskell-platform
haskell-platform @2009.2.0.2 (devel, haskell)
Description: This is the the Haskell
Warren Harris warrensomeb...@gmail.com writes:
Then I uninstalled everything, installed GHC-6.12.1- i386.pkg, then
Haskell Platform 2010.1.0.0, and rebooted... and then experienced
the cabal problem.
BTW, there's some description of linker flags here:
Don Stewart d...@galois.com writes:
The beta of the 2010.2.0.0 release is now up, which is based on GHC
6.12.
Hang on, you just announced 2010.1.0.0... have you suddenly released
_another_ major version? :p
--
Ivan Lazar Miljenovic
ivan.miljeno...@gmail.com
IvanMiljenovic.wordpress.com
Günther Schmidt wrote:
I have some questions that are related to commercial software
development (in Haskell) which I don't think fit well on this list.
Really? This is haskell-cafe. If its even tangentially haskell
related I'm sure this this list would be fine.
According to
Hi
David Leimbach wrote:
On Mon, Mar 22, 2010 at 6:10 AM, Johan Tibell johan.tib...@gmail.com
wrote:
On Mon, Mar 22, 2010 at 1:16 PM, Johann Höchtl
johann.hoec...@gmail.com wrote:
My question or discussion point: Why not depreciate [Char]
altogether
Hello Erik,
all right then.
I've written a commercial Desktop application in Haskell for the Win32
platform.
The one thing missing is Software Copy Protection, ie. a software
licensing mechanism. When I google for Software Copy Protection I get
a lot of results, commercial products
Günther Schmidt wrote:
I've written a commercial Desktop application in Haskell for the Win32
platform.
The one thing missing is Software Copy Protection, ie. a software
licensing mechanism. When I google for Software Copy Protection I get
a lot of results, commercial products
Fundamentally, Software Copy Protection (as well as DRM) is an
unsolvable problem. It's basically like saying that you want to give
someone something and not give it to them at the same time. With
physical products there are physical properties that you can use to
accomplish some aspects of
Hi Günther
Congratulations!
You might find this article useful. Though it only mentions one
particular system Armadillo, there are a number of good tips like
releasing updates frequently so the binaries change, and the author is
well regarded in micro software circles.
Hello,
I’m relatively new to Haskell.
I’m wondering if it exist a tool to graphically represent Haskell code.
Look at the little graphics at: http://www.haskell.org/arrows/index.html (and
following pages) from Ross Paterson.
http://www.haskell.org/arrows/index.htm
If found these very useful
On 23 March 2010 10:02, Dupont Corentin corentin.dup...@gmail.com wrote:
I’m relatively new to Haskell.
Welcome!
I’m wondering if it exist a tool to graphically represent Haskell code.
Look at the little graphics at: http://www.haskell.org/arrows/index.html (and
following pages) from Ross
Hello Erik,
the software I wrote and am about to sell was developed for use by
German Hospitals only. It's being used to calculate a departments share
of the revenues paid by the insurance companies for a case and needed
every 6 months by the hospitals when it enters budget negotiations with
Günther Schmidt wrote:
Hello Erik,
the software I wrote and am about to sell was developed for use by
German Hospitals only. It's being used to calculate a departments share
of the revenues paid by the insurance companies for a case and needed
every 6 months by the hospitals when it
Reminds me of To Dissect a Mockingbird [http://dkeenan.com/Lambda/].
On Tue, Mar 23, 2010 at 7:12 AM, Ivan Miljenovic
ivan.miljeno...@gmail.com wrote:
On 23 March 2010 10:02, Dupont Corentin corentin.dup...@gmail.com wrote:
I’m relatively new to Haskell.
Welcome!
I’m wondering if it exist a
Gregory Collins wrote:
wren ng thornton w...@freegeek.org writes:
I'm still on 10.5.8. I don't have cabal-install installed yet, but I just
installed GHC-6.12.1/HP-2010.1.0.0. I can verify that ghci works fine so
far. I'll check out cabal-install in the next couple days.
If there is an issue
On 23 March 2010 14:25, wren ng thornton w...@freegeek.org wrote:
w...@semiramis:~ $ ls /usr/local
ls: /usr/local: No such file or directory
w...@semiramis:~ $ ls /usr/bin/cabal
ls: /usr/bin/cabal: No such file or directory
But http://hackage.haskell.org/platform/new/contents.html tells me
I've proposed to do it at this GSOC. More exactly, it is still in the
feedback phase, I'll integrate all feedback in another blog post and in an
application for GSOC tomorrow. If you want to read about it in this stage,
you can visit my blog [0]. Feedback on reddit can be seen here[1].
The
On Mon, Mar 22, 2010 at 7:02 PM, Dupont Corentin
corentin.dup...@gmail.com wrote:
Hello, I’m relatively new to Haskell.
I’m wondering if it exist a tool to graphically represent Haskell code.
...
Let’s try to do it on a simple example, as an exercise:
f = Map (+1)
Your graphic for f = map
ivan.miljenovic:
Don Stewart d...@galois.com writes:
The beta of the 2010.2.0.0 release is now up, which is based on GHC
6.12.
Hang on, you just announced 2010.1.0.0... have you suddenly released
_another_ major version? :p
2010.1.0.0 is definited as a 'beta' for 2010.2
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