On Monday 09 July 2007 17:42, Thomas Conway wrote:
I don't know if you saw the following linked off /.
http://www.itwire.com.au/content/view/13339/53/
An amazon link for the book is here:
http://www.amazon.com/Computer-Science-Reconsidered-Invocation-Expression/d
p/0471798142
The basic
On Mon, 2007-07-09 at 10:30 +1000, Donald Bruce Stewart wrote:
Another idea I've been pondering is allowing people to add links to
documentation for libraries
My main worry about Hackage is that it is often hard to tell the current
status of packages - it could easily develop into a huge list
ketil:
On Mon, 2007-07-09 at 10:30 +1000, Donald Bruce Stewart wrote:
Another idea I've been pondering is allowing people to add links to
documentation for libraries
My main worry about Hackage is that it is often hard to tell the current
status of packages - it could easily develop
On 7/9/07, Ketil Malde [EMAIL PROTECTED] wrote:
The current deliverables seem to consist of a tar file and a package
description, neither of them accurately dated.
Clearly we need to store them in a treap. :-)
--
Dr Thomas Conway
[EMAIL PROTECTED]
Silence is the perfectest herald of joy:
I
On 7/9/07, Daniel McAllansmith [EMAIL PROTECTED] wrote:
I wouldn't want to comment on the validity of his claim, maybe he's wrong, or
maybe he's... well, anyway... what I will say is I got a chuckle out of
the 'Citations' that Amazon lists.
As amusing as that thought is, it seems that this is
Hello Andrew,
Sunday, July 8, 2007, 7:07:59 PM, you wrote:
Actually, LZW works surprisingly well for such a trivial little
algorithm... When you compare it to the complexity of an arithmetic
coder driven by a high-order adaptive PPM model (theoretically the best
general-purpose algorithm
Hello
In the archives of haskell-cafe I found a mention of constraints on
datatypes as a mis-feature of Haskell. In particular, that they're not
propagated well. Can someone elaborate on that?
Also, are they still considered a mis-feature with the emergence of GADTs ?
If I have
data GADT a
It looks like Amazon's citation database is mistakenly using the index
for the book _Beating Depression_ by John Rush (Toronto: John Wiley
Sons, Canada Ltd., 1983).
Yes it is so. Amazon.com mistakenly thinks that the given book is a
new edition of the book titled beating depression.
Amazon
voigt:
Hi,
I can't get http://lambdabot.codersbase.com/ to work for me. Whatever
input = No lambdabot process
Is that a known issue, not the right URL, ...?
Thanks,
Janis.
Right URL, but Jason's not running lambdabot at the moment. You can
access our bot via IRC though.
On Mon, Jul 09, 2007 at 02:42:49PM +1000, Donald Bruce Stewart wrote:
Processing larger amounts of data, compression, serialisation and calling C.
Just a thought: is it worth sticking this up on the wiki?
Phil
--
http://www.kantaka.co.uk/ .oOo. public key: http://www.kantaka.co.uk/gpg.txt
Donald Bruce Stewart wrote:
Right URL, but Jason's not running lambdabot at the moment. You can
access our bot via IRC though. http://haskell.org/haskellwiki/IRC_channel
Yup, but I assume that would mean bothering others with my experiments
with some lambdabot features ;-)
I'll better try
Doesn't Haskell already implement the 3-valued logic (True, False, NULL), that
Karl Fant proposes (see papers at
http://www.theseusresearch.com/invocation%20model.htm) as an alternative to
centralised clock-based coordination, by postulating that every data type
includes the bottom value?
I
Hi all
On 9 Jul 2007, at 06:42, Thomas Conway wrote:
I don't know if you saw the following linked off /.
http://www.itwire.com.au/content/view/13339/53/
[..]
The basic claim appears to be that discrete mathematics is a bad
foundation for computer science. I suspect the subscribers to this
On 15:42 Mon 09 Jul , Thomas Conway wrote:
I don't know if you saw the following linked off /.
http://www.itwire.com.au/content/view/13339/53/
I read that earlier and his comments, such as
This concept of 'process expression' is, he says, a common thread
running through the various
On Sun, 2007-07-08 at 16:40 -0400, Brandon S. Allbery KF8NH wrote:
On Jul 8, 2007, at 16:36 , D.V. wrote:
I finally got it to work with onResponse : I traced each possible
response to see which one was fired when clicking the close button
And what was the result?
Great, another place
Haskell XML Toolbox 7.2
I would like to announce a new version of the Haskell XML Toolbox.
This is mainly a bug fix release, but there is one new module
for converting data between user defined types and the
HXT DOM structure.
This new modules enables the simple persistent storage and retrieval
Hello,
Who's our SoC hackage guy? To do list right here!
The HackageDB project is for now concentrating on another subject. I see
the necessity of adding search features and additionally tags, but in
the moment I work on automatic generation of Haddock documentation.
The progress and a to do
Hi,
I'm trying to translate Example 2.3.3 (simple symbolic differentation) from
Structure and Interpretation of Computer Programs into Haskell.
Here is code that works (as far as see):
---
data Term b = Var String | Const b | Sum (Term b) (Term b) | Prod (Term b)
(Term b)
newSum (Const a)
I'd like to be able to use MT to build a list like:
[MT (T1a,1), MT (T1b,3)]
And I'd like to read str with:
read $ show str
Substituting return (m) with return (MT m) leads to error messages
like: Ambiguous type variable `e' in the constraints
which is the important hint! the parser used for
Try liftM3 from Control.Monad
let get = xmlGetWidget xml castToEntry
liftM3 UserPanel (get signatureEntry) (get passwordEntry) (get
repeatEntry)
Adde wrote:
Hi.
I'm toying around with GTK2Hs and one of the things I'm doing
is stuffing a bunch of widgets in a record.
The problem is that
On Monday 09 July 2007, Daniil Elovkov wrote:
Hello
In the archives of haskell-cafe I found a mention of constraints on
datatypes as a mis-feature of Haskell. In particular, that they're not
propagated well. Can someone elaborate on that?
Also, are they still considered a mis-feature with
Adde wrote:
signatureEntry - xmlGetWidget xml castToEntry signatureEntry
passwordEntry - xmlGetWidget xml castToEntry passwordEntry
repeatEntry - xmlGetWidget xml castToEntry repeatEntry
return UserPanel {userPanelSignatureEntry = signatureEntry,
userPanelPasswordEntry =
On Mon, Jul 09, 2007 at 03:55:52PM +0200, Christian Maeder wrote:
Hi,
I would like haskell to accept the following (currently illegal)
expressions as syntactically valid prefix applications:
f = id \ _ - []
g = id let x = [] in x
h = id case [] of [] - []
i = id do []
j = id if True then
On Mon, Jul 09, 2007 at 06:05:44PM +0200, Marc Weber wrote:
Another idea I've been pondering is allowing people to add links to
documentation for libraries, from their hackage page. We have a fair
few libs documented in blog form, here,
Beeing able adding some comments (wiki style) would be
On Mon, Jul 09, 2007 at 06:53:15PM +1000, Donald Bruce Stewart wrote:
phil:
On Mon, Jul 09, 2007 at 02:42:49PM +1000, Donald Bruce Stewart wrote:
Processing larger amounts of data, compression, serialisation and calling
C.
Just a thought: is it worth sticking this up on the wiki?
Stefan O'Rear wrote:
On Mon, Jul 09, 2007 at 03:55:52PM +0200, Christian Maeder wrote:
Hi,
I would like haskell to accept the following (currently illegal)
expressions as syntactically valid prefix applications:
f = id \ _ - []
g = id let x = [] in x
h = id case [] of [] - []
i = id do []
j =
Bulat Ziganshin wrote:
Hello Andrew,
Sunday, July 8, 2007, 7:07:59 PM, you wrote:
i don't think that ppm is so complex - it's just probability of
symbol in some context. it's just too slow in naive implementation
Oh, sure, the *idea* is simple enough. Trying to actually *implement* it
On Mon, Jul 09, 2007 at 09:05:55PM +0100, Andrew Coppin wrote:
OK, can somebody explain to me *really slowly* exactly what the difference
between an existential type and a rank-N type is?
(I couldn't find much of use on the wiki. I have now in fact written some
stuff there myself, but since
On Mon, Jul 09, 2007 at 09:15:07PM +0100, Andrew Coppin wrote:
Bulat Ziganshin wrote:
Hello Andrew,
Sunday, July 8, 2007, 7:07:59 PM, you wrote:
i don't think that ppm is so complex - it's just probability of
symbol in some context. it's just too slow in naive implementation
Oh,
OK, can somebody explain to me *really slowly* exactly what the
difference between an existential type and a rank-N type is?
(I couldn't find much of use on the wiki. I have now in fact written
some stuff there myself, but since I don't understand it in the first
place, I'm having difficulty
which is the important hint! the parser used for 'read' depends on
the return type, but the existential type _hides_ the internal type
which would be needed to select a read parser.
forall e . (MyClass e, Show e, Read e) = MT (e,Int)
the 'Read' there ensures that we only inject types that
Stefan O'Rear wrote:
On Mon, Jul 09, 2007 at 09:15:07PM +0100, Andrew Coppin wrote:
Oh, sure, the *idea* is simple enough. Trying to actually *implement* it
correctly is something else... ;-)
Took me about an hour and 50 lines of code (about a year ago - this was
one of my first
Stefan O'Rear wrote:
All users should worry about is Quantifiers.
A quantifier is an operator on types which defines a variable in some
way.
OK...
id has type :: ∀α. α → α
toUpper (can) have type :: ∃α. α → α
So... you're saying that id:: x - x works for *every* possible choice
of
On Mon, Jul 09, 2007 at 10:01:06PM +0100, Andrew Coppin wrote:
Bulat Ziganshin wrote:
Hello Andrew,
Monday, July 9, 2007, 12:36:25 AM, you wrote:
OK. So that's just the GHC binary itself, right?
it's INSTALLER
Ah. That explains the size then...
Is it safe to install two
On Mon, Jul 09, 2007 at 09:57:14PM +0100, Andrew Coppin wrote:
Stefan O'Rear wrote:
id has type :: ∀α. α → α
toUpper (can) have type :: ∃α. α → α
So... you're saying that id:: x - x works for *every* possible choice of
x, but toUpper :: x - x works for *one* possible choice of x?
Andrew Coppin wrote:
I stand in awe of people who actually understand what universal and
existential actually mean... To me, these are just very big words that
sound impressive.
I offer to relieve that with http://www.vex.net/~trebla/allsome.txt
I think of formal logic as clarifying thought
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure. This felt like cheating,
or at least like using a screwdriver as a crowbar, to be less
judgmental.
On Monday 09 July 2007, Dave Bayer wrote:
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure. This felt like cheating,
or at least like using a screwdriver as a
http://xkcd.com/c287.html
import Data.Array
import Control.Monad
-- exactly n v
-- items in v that sum to exactly n
-- returns list of solutions, each solution list of items
exactly :: (Real a) = a - Array Int a - [[a]]
exactly 0 v = return []
exactly n v = do
i - indices v
guard (v!i = n)
I'm please to announce HCL 1.0 - a library for building command line
interfaces. The library exports a mix of low and high-level functions
for building programs which gather simple values, ask yes/no
questions, or present hierarchical menus. The library is not intended
to do complex, full-screen
All -
I tried emailing this to Daan, but I can't find an up-to-date
email address, so I hope this is an acceptable alternative :). I'm
looking for someone who knows the guts of Parsec a bit, or has done some
automated testing of a Parsec parser.
I'm interested in using Parsec for
On 7/9/07, Andrew Coppin [EMAIL PROTECTED] wrote:
OK, can somebody explain to me *really slowly* exactly what the
difference between an existential type and a rank-N type is?
One important difference is that Hugs supports existential
quantification, but not rank-N types. (It does support
Use one of the general monadic combinators given in Control.Monad:
liftM3 UserPanel (xmlGetWidget xml castToEntry signatureEntry)
(xmlGetWidget xml castToEntry passwordEntry)
(xmlGetWidget xml castToEntry repeatEntry)
or
return UserPanel
`ap`
I am having trouble exporting multiple instances of a polymorphic function
similar to the example in the Haskell 98 Foreign Function Interface 1.0
addendum (page 6). My specific code is below:
---begin test.hs-
module Test() where
import
I'm trying to get 'hide' but failed to install 'yi'.
I followed instructions at page http://haskell.org/hawiki/hIDE_2fDesign but
can't succeed in executing
darcs get http://scannedinavian.org/repos/yi/
the mentioned http isn't responding.
Can you please advise where can I get yi?
TIA.
bayer:
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure. This felt like cheating,
or at least like using a screwdriver as a crowbar, to be less
sascha.boehme:
Hello,
Who's our SoC hackage guy? To do list right here!
The HackageDB project is for now concentrating on another subject. I see
the necessity of adding search features and additionally tags, but in
the moment I work on automatic generation of Haddock documentation.
On Mon, Jul 09, 2007 at 08:43:03PM +0400, Vadim wrote:
I'm trying to get 'hide' but failed to install 'yi'.
I followed instructions at page http://haskell.org/hawiki/hIDE_2fDesign but
can't succeed in executing
HaWiki is no longer used, has not been updated for months, and on the
FrontPage
Hi All,
I notice that Data.ByteString has span and spanEnd. Is there a known
particular reason why dropWhile and takeWhile don't have corresponding
*End functions? If not, what is the protocol for adding them?
cheers,
T.
--
Dr Thomas Conway
[EMAIL PROTECTED]
Silence is the perfectest herald of
drtomc:
Hi All,
I notice that Data.ByteString has span and spanEnd. Is there a known
and break/breakEnd.
particular reason why dropWhile and takeWhile don't have corresponding
*End functions? If not, what is the protocol for adding them?
There's no reason -- we couldn't decide on whether
drtomc:
Well, maybe I shoud be asking a higher level question then.
I have a function
tidy = reverse . dropWhile punk . reverse . dropWhile punk
where
punk = isPunctuation . chr . fromIntegral
which is leading to a significant amount of allocation, and you can see why.
The way
Donald Bruce Stewart wrote:
I'd just manually write a 'tidy' loop (in the Data.ByteString style) (which
would avoid all allocations), since it seems pretty useful.
That would indeed be very useful to have as a library function. I've
pined for Python's strip() string method (removes leading
On Jul 9, 2007, at 6:52 PM, Donald Bruce Stewart wrote:
bayer:
Learning Haskell, the Prelude.ShowS type stood out as odd, exploiting
the implementation of lazy evaluation to avoid explicitly writing an
efficient concatenable list data structure.
See also
Thomas Conway wrote:
Well, maybe I shoud be asking a higher level question then.
I have a function
tidy = reverse . dropWhile punk . reverse . dropWhile punk
where
punk = isPunctuation . chr . fromIntegral
which is leading to a significant amount of allocation, and you can see
why.
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