Thomas Hartman wrote:
I don't think this will work.
From
http://www.haskell.org/ghc/docs/latest/html/libraries/fgl/src/Data-Graph-Inductive-Graph.html
the minimal implementatin for Graph is
-- | Minimum implementation: 'empty', 'isEmpty', 'match', 'mkGraph',
'labNodes'
-- |
Benja Fallenstein wrote:
However, if you'd be able to live with
data CGraph a b = CGraph [LNode a] (Node - Node - b)
then you should be able to write the instance like this--
instance Graph CGraph where
empty = CGraph [] (const $ error Node not in graph)
isEmpty (CGraph xs _) =
Hello Jon,
Monday, January 21, 2008, 1:18:52 AM, you wrote:
You're missing out on a lot if this isn't available for Haskell yet. I didn't
realise just how invaluable this is until a system upgrade broke it and I
really struggled to write OCaml code without it: I don't know how I managed
Hi Christian,
On Jan 21, 2008 10:57 AM, Christian Maeder [EMAIL PROTECTED] wrote:
Thanks for pointing out this proposal. The actual problem is mkGraph
that needs all the many edges created beforehand (that's what I wanted
to avoid).
Well, uh, at the risk of being obvious, if you can avoid
I think you should try again, the link is not dead.
On Sun, 20 Jan 2008 21:54:08 +0100, Jon Harrop [EMAIL PROTECTED]
wrote:
I'd like to compare the performance of Parsec to other parsers but the
only
reference to a benchmark I have found is a dead link from one of the
papers
about
On Thu, 17 Jan 2008, Simon Peyton-Jones wrote:
| To give a precise example: If I have a sequence of 'map's
| map f0 . map f1 . ... . map fn
| then there is some length where this is no longer collapsed to a single
| 'map'?
(a) GHC tries to do as much as possible in a single iteration of
Bertram
Thanks for your help, I tried to solve the problem this weekend but I have
some dudes.
My reasoning is:
The sequence is [1,a1,a2,a3,..] where a1 = h 1 1, a2 = h 1 a1, and so on
So, I want to construct the list of lists
[[1,a1,a2,a3],
[h 1 1, h 1 a1, h 1 a2,..],
[h a1 1, h a1 a1, h a1
Duncan,
I got the latest cabal. The stack overflow is fixed. But the install
command still does not work (on a very simple package). Attached is
the verbose output. It does not like to proceed somewhere between
configure and build. But the verbose is not telling why!
I also attached my cabal
Jose Luis Reyes F. wrote:
Thanks for your help, I tried to solve the problem this weekend but I have
some dudes.
My reasoning is:
The sequence is [1,a1,a2,a3,..] where a1 = h 1 1, a2 = h 1 a1, and so on
So, I want to construct the list of lists
[[1,a1,a2,a3],
[h 1 1, h 1 a1, h 1
On Sat, Jan 19, 2008 at 08:36:55PM +0100, Alfonso Acosta wrote:
On Jan 19, 2008 2:36 PM, David Roundy [EMAIL PROTECTED] wrote:
Using ghc 6.6, but I've since isolated the bug as being unrelated to the
IORefs and threading, it was in an FFI binding that somehow never died
until I was testing
Hi, I try to undestand why this code dosen't work
f :: (Num a)=Integer-a
f i = i
Integer is an instance of Num, so why does this code produce error:
Couldn't match expected type 'a' againsta inferred type 'Integer' ...
___
Haskell-Cafe mailing list
2008/1/21 Alexander Seliverstov [EMAIL PROTECTED]:
Hi, I try to undestand why this code dosen't work
f :: (Num a)=Integer-a
f i = i
Integer is an instance of Num, so why does this code produce error:
Couldn't match expected type 'a' againsta inferred type 'Integer' ...
But the type of
Call for Papers
ICFP 2008: International Conference on Functional Programming
Victoria, BC, Canada, 22-24 September 2008
http://www.icfpconference.org/icfp2008
Submission deadline: 2 April 2008
ICFP 2008 seeks original
Hi Derek,
Thanks for the reply.
On 20/01/2008, Derek Elkins [EMAIL PROTECTED] wrote:
You may want to consider using the other side of Data.Binary rather than
the Binary class. The -class- Binary is intended for de/serialization
when you don't care about the format. From the documentation:
Hello,
It's a _complete_ graph, i.e. there is an edge between every two nodes.
I want to compute the minimum spanning tree. Eventually I want to have a
sub-optimal solution for the travelling salesman problem (TSP).
A direct solution for this problem would be:
-- | place a f-minimal
Alexander Seliverstov [EMAIL PROTECTED] writes:
How does caller choose which particular instance of Num they want?
They specify the type... or just pass the result to
something that specifies the type. Try it in ghci:
Prelude let f:: Integral i = Integer - i; f = fromIntegral
Prelude let g ::
How does caller choose which particular instance of Num they want?
In object-oriented language If function return type is an interface it means
that it can return any implementation of this interface, but caller can't
choose which particular inplementation they want.
What the difference between
| I think I also found a typo:
Quite right, thanks -- now fixed.
| Recently I found that specialisation interacts in an unexpected way with
| explicit RULES (and with inlining). I used a function multiple times and
| this seemed to make GHC specialising this function (although I did not
| used a
On Jan 20, 2008, at 1:03 PM, Yitzchak Gale wrote:
Generating an infinite list from a random generator burns up
the generator, making it unusable for any further calculations.
That's what the split function is for. ^_^
- Jake
___
Haskell-Cafe
So, the function type (Num a)=Integer-a means that return value of this
function can be cast to any particular instance of class Num.
Ok. I have a my own class class A a and want to write function like this
f:: (A a)=Integer-a. Can I do it?
2008/1/21, Jon Fairbairn [EMAIL PROTECTED]:
2008/1/21 Alexander Seliverstov [EMAIL PROTECTED]:
So, the function type (Num a)=Integer-a means that return value of
this function can be cast to any particular instance of class Num.
Ok. I have a my own class class A a and want to write function like
this f:: (A a)=Integer-a. Can I do it?
1) Can anyone tell me how I can build Yi or point me to a binary release of
that editor?
I tried to follow the instructions on
http://www.nobugs.org/developer/yi/building.html but got a missing component
error each time.
2) When if ever is Data.ByteString going to be the default string
On Mon, 2008-01-21 at 19:12 +0100, Cetin Sert wrote:
1) Can anyone tell me how I can build Yi or point me to a binary
release of that editor?
I tried to follow the instructions on
http://www.nobugs.org/developer/yi/building.html but got a missing
component error each time.
You need
A deployment of HAppS, AlexJ et al's web framework for Haskell, at openomy,
The latest release of our API is written in Haskell using the new HAppS
framework.
The good news,
Since being in production, we've so far found very few issues and
everything runs quickly and
On 2008.01.21 19:12:26 +0100, Cetin Sert [EMAIL PROTECTED] scribbled 1.9K
characters:
1) Can anyone tell me how I can build Yi or point me to a binary release
of that editor?
I tried to follow the instructions on
http://www.nobugs.org/developer/yi/building.html but got
a missing
Hello,
On Mon, Jan 21, 2008 at 07:12:26PM +0100, Cetin Sert wrote:
2) When if ever is Data.ByteString going to be the default string
representation in GHC?
Why would you need such a thing? ByteStrings don't have any unicode
support, and they can be quite slow for small strings. They are just a
John, Don and I are pleased to announce the beginning of the public beta
programme for our upcoming book, Real World Haskell. For further
details, please see the following blog entry:
http://www.realworldhaskell.org/blog/2008/01/21/finally-the-public-beta-programme-begins/
Thanks to all of the
On Mon, 2008-01-21 at 16:18 +, Lauri Pesonen wrote:
Hi Derek,
Thanks for the reply.
On 20/01/2008, Derek Elkins [EMAIL PROTECTED] wrote:
You may want to consider using the other side of Data.Binary rather than
the Binary class. The -class- Binary is intended for de/serialization
How does caller choose which particular instance of Num they want?
By passing the type they want. That's what the Num a = thingy does.
In object-oriented language If function return type is an interface it means
that it can return any implementation of this interface, but caller can't
Hey, I knew about the forall (I use that to represent OO style
collections, very handy), but not about the exists. Thanks. But GHC
6.8.2 (with -fglasgow-exts) does not seem to accept this exists
keyword?
Does a book or document already exist (except the website) that tells
more about not
Oops, I just replied to another message asking for such a book!
Amazing that my prayers are answered even before I asked them ;-)
Peter
On Mon, 2008-01-21 at 11:53 -0800, B
ryan O'Sullivan wrote:
John, Don and I are pleased to announce the beginning of the public beta
programme for our
On Mon, 2008-01-21 at 22:36 +0100, Peter Verswyvelen wrote:
Hey, I knew about the forall (I use that to represent OO style
collections, very handy), but not about the exists. Thanks. But GHC
6.8.2 (with -fglasgow-exts) does not seem to accept this exists
keyword?
That's because it isn't GHC
Bryan O'Sullivan [EMAIL PROTECTED] wrote:
We look forward to your feedback!
My browser shows me this:
Dat geev en Fehler, as
http://book.realworldhaskell.org/beta/funcstypes.html laadt wöör: Tiet
op Server aflopen
Verbinnen bestunn na book.realworldhaskell.org an Port 80
I think you have
Am Montag, 21. Januar 2008 20:53 schrieb Bryan O'Sullivan:
John, Don and I are pleased to announce the beginning of the public beta
programme for our upcoming book, Real World Haskell. For further
details, please see the following blog entry:
Am Montag, 21. Januar 2008 21:55 schrieb Derek Elkins:
On Mon, 2008-01-21 at 22:36 +0100, Peter Verswyvelen wrote:
Hey, I knew about the forall (I use that to represent OO style
collections, very handy), but not about the exists. Thanks. But GHC
6.8.2 (with -fglasgow-exts) does not seem to
On Mon, 2008-01-21 at 10:15 -0500, Steve Lihn wrote:
Duncan,
I got the latest cabal. The stack overflow is fixed. But the install
command still does not work (on a very simple package). Attached is
the verbose output. It does not like to proceed somewhere between
configure and build. But the
I wrote:
Generating an infinite list from a random generator burns up
the generator, making it unusable for any further calculations.
Jake McArthur wrote:
That's what the split function is for. ^_^
Yes, that is a nice approach. I have been avoiding it due to
the following comment in the docs
I wrote:
That said, looking around briefly, I came up with this paper
by L'Ecuyer et al that does seem to describe a decent
random generator with properties of split worked out:
Derek Elkins wrote:
According to the documentation
That -is- what we have.
No, we have a much older algorithm of
On Tue, 2008-01-22 at 02:24 +0200, Yitzchak Gale wrote:
I wrote:
That said, looking around briefly, I came up with this paper
by L'Ecuyer et al that does seem to describe a decent
random generator with properties of split worked out:
Derek Elkins wrote:
According to the documentation
-- Yi
that's the error message I got following the instructions on
http://www.nobugs.org/developer/yi/building.html
setup: At least the following dependencies are missing:
fingertree -any
make: *** [dist/setup-config] Error 1
Where can I get fingertree from? Do I need a specific version of
Achim Schneider wrote:
Speaking of that, the generators that come in the box are awfully slow,
I ended up calling into
http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/SFMT/index.html
via the ffi.
Yes, it would be nice to have the Mersenne Twister available.
Not only for speed - it is widely
cetin.sert:
-- Yi
that's the error message I got following the instructions on
[1]http://www.nobugs.org/developer/yi/building.html
setup: At least the following dependencies are missing:
fingertree -any
make: *** [dist/setup-config] Error 1
Where can I get
Hi,
I don't think we included this in the version we checked in.
It should be fairly easy to add to the current implementation: it will mirror
ReadTVar except that the old value is always selected.
I'm afraid I can't remember exactly why we didn't include it. One reason might
have been that
Thank you for the positive responses. The best kind of feedback is
the kind that makes me have to think, and I've done alot of thinking.
_Regarding monads and interfaces_
Paul Johnson wrote:
1: Your GameState type can itself be made into a monad. Take a look
at the All About Monads tutorial,
Indeed, from us at Openomy, we thank all those involved in HAppS for
their work, and more importantly, their help with all our questions
along the way. :)
We're happy to answer any questions anyone may have on our experience,
implementation, etc.
Ian
On 1/21/08, Don Stewart [EMAIL PROTECTED]
(¬) :: Bool → Bool
(¬) q = not q
q = True
¬ q : parser error on input
q ¬ : parser error (possibly incorrect indentation)
(¬ q) : Couldn't match expected type `Bool - t' against inferred type
`Bool' In the expression: (� True) In the definition of `it': it = (� True)
*
(q ¬) : False
(Why) is it
Hello Alexander,
Monday, January 21, 2008, 7:36:18 PM, you wrote:
How does caller choose which particular instance of Num they want?
In object-oriented language If function return type is an interface
it means that it can return any implementation of this interface,
but caller can't choose
Hello Cetin,
Monday, January 21, 2008, 9:12:26 PM, you wrote:
2) When if ever is Data.ByteString going to be the default string
representation in GHC?
there is no need, you can just use it as any other type. having rich
library is enough condition
--
Best regards,
Bulat
Hello Jon,
Monday, January 21, 2008, 9:28:09 PM, you wrote:
Ok. I have a my own class class A a and want to write function like
this f:: (A a)=Integer-a. Can I do it?
But in general you are going to want something a bit more
useful, which means that you have to have a path from
Integer to
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