On 2007-10-15, [EMAIL PROTECTED] wrote:
ok writes:
On 11 Oct 2007, at 1:00 pm, [EMAIL PROTECTED] wrote:
An anonymous called ok writes:
I am not anonymous. That is my login and has been since 1979.
Oh, bother...
According to my imperfect knowledge of English, an anonymous is
Now that that works, one more question. Is it possible to hide the r that
is attached to every single type? For example to do something like this
(which doesn't compile):
No answer needed. Duh.. I can just pick r to be any type (like ()).
I've got intuitionistic logic and classic logic in
On Sun, Oct 14, 2007 at 21:24:50 +0200, Gour wrote:
On Sun, 14 Oct 2007 15:22:13 +0100
Ian Lynagh [EMAIL PROTECTED] wrote:
We could perhaps have web pages on projects.haskell.org, and some sort
of bug tracker on bugs.haskell.org (or perhaps trac.haskell.org etc).
Some days ago I stumbled upon
The really amazing thing about the IO Monad in Haskell is that
there *isn't* any magic going on. An level of understanding
adequate for using the I/O and State monads stuff (that is,
adequate for practically anything analogous to what you might
do in another language) goes like this:[...]
On Sun, Oct 14, 2007 at 15:22:13 +0100, Ian Lynagh wrote:
On Wed, Oct 10, 2007 at 05:05:28PM +0100, Magnus Therning wrote:
I've almost reached a state where I wouldn't be ashamed of sharing the
code so I looked into my options of free hosting.
It seems I only have one option for publishing
On 10/14/07, Peter Verswyvelen [EMAIL PROTECTED] wrote:
If you want I can dig up my old source code where I converted a random number
generator from a purely functional approach to a monadic approach, but I'm not
sure reading it would help you, it's creating the code yourself that will be
On Mon, 15 Oct 2007 07:36:55 +0100
Magnus Therning [EMAIL PROTECTED] wrote:
There is support for darcs in tracs as well. I never got around to
writing a blog post about setting up darcs+trac+lighttpd on Debian and
by now I fear I've forgotten how I did it... I remember it being
remarkably
[EMAIL PROTECTED] wrote:
However, arguably the biggest imperatives for Haskell 98 was to remove
features that would confuse undergraduates.
[...]
People want to write map instead of fmap. We could have come up
with an alternative name for the list-version of map and not showed
map to newbies.
Actually I stopped bothering long ago about 'understanding monads'.
I think that's a shame, because when I wrote the source code myself to get
from a pure functional approach (passing the object from function to
function as an extra argument) to a monadic approach, it was a real eye
opener.
Magnus Therning wrote:
There is support for darcs in tracs as well.
Gour wrote:
I was playing with it in the past, but it's 3rd party,
ie. Trac does not have official support.
I happen to be looking for a project mgmt framework
right now.
It seems to me that the opposite is true. Trac is a
Richard A. O'Keefe writes:
(2) The mathematical background of Haskell is extremely important
for implementations. Some important data structures and
techniques are practical in large part because of the kinds of
optimisations that are only straightforward in a language that
has
On Mon, 15 Oct 2007, Peter Verswyvelen wrote:
Actually I stopped bothering long ago about 'understanding monads'.
I think that's a shame, because when I wrote the source code myself to get
from a pure functional approach (passing the object from function to
function as an extra argument) to
Claus Reinke wrote:
but calling split-base base goes directly against all basic
assumptions of all packages depending on base.
The new base will have a new version number. There is no expectation of
compatibility when the major version is bumped; but we do have an informal
convention that
On Mon, 15 Oct 2007 11:39:27 +0200
Yitzchak Gale [EMAIL PROTECTED] wrote:
It seems to me that the opposite is true. Trac is a
mature app with a huge community of people
supporting it and writing plugins, including some
departments at NASA. It is being used successfully
for many large
On Mon, Oct 15, 2007 at 09:24:28 +0200, Gour wrote:
On Mon, 15 Oct 2007 07:36:55 +0100
Magnus Therning [EMAIL PROTECTED] wrote:
There is support for darcs in tracs as well. I never got around to
writing a blog post about setting up darcs+trac+lighttpd on Debian and
by now I fear I've
Yes, exactly, but how does one call the way of programming without
monads / do notation then, explicitly passing the object? Does this
approach have a name? Or just non-monadic style?
Henning Thielemann wrote:
On Mon, 15 Oct 2007, Peter Verswyvelen wrote:
Actually I stopped bothering long
Peter Verswyvelen writes:
Yes, exactly, but how does one call the way of programming without monads
/ do notation then, explicitly passing the object? Does this approach
have a name? Or just non-monadic style?
In the jargon of CPS, somehow related to Monads, the constructions which
do not
On 10/15/07, Peter Verswyvelen [EMAIL PROTECTED] wrote:
Yes, exactly, but how does one call the way of programming without
monads / do notation then, explicitly passing the object? Does this
approach have a name? Or just non-monadic style?
the painful style ?
On 10/15/07, apfelmus [EMAIL PROTECTED] wrote:
Of course, the solution is to first drop n elements and then take
tails instead of dropping n elements every time.
map (drop n) . tails = tails . drop n
O(m*n) O(m)
Nice identity. I'll remember this one.
With
2007/10/15, Felipe Lessa [EMAIL PROTECTED]:
On 10/15/07, apfelmus [EMAIL PROTECTED] wrote:
Of course, the solution is to first drop n elements and then take
tails instead of dropping n elements every time.
map (drop n) . tails = tails . drop n
O(m*n)
Felipe Lessa wrote:
apfelmus wrote:
Of course, the solution is to first drop n elements and then take
tails instead of dropping n elements every time.
map (drop n) . tails = tails . drop n
O(m*n) O(m)
Nice identity. I'll remember this one.
Oops, please don't
but calling split-base base goes directly against all basic
assumptions of all packages depending on base.
The new base will have a new version number. There is no expectation of
compatibility when the major version is bumped; but we do have an informal
convention that minor version bumps
On Oct 15, 2007, at 7:01 , Yitzchak Gale wrote:
But I think we are still at the stage where a programmer
who wants practical results is better off starting out
by learning how to use monads in practice, not by
delving into category theory.
No argument from a Haskell standpoint. Still, when
On Oct 15, 2007, at 7:02 , [EMAIL PROTECTED] wrote:
IO is different, you *cannot* make it non-monadic.
Not really true; it's just much more painful. You just e.g.
explicitly do what the ghc library's implementation of IO does:
construct a chain of functions with an opaque (and
On Oct 15, 2007, at 7:02 , david48 wrote:
On 10/15/07, Peter Verswyvelen [EMAIL PROTECTED] wrote:
Yes, exactly, but how does one call the way of programming without
monads / do notation then, explicitly passing the object? Does this
approach have a name? Or just non-monadic style?
the
On Oct 15, 2007, at 7:59 , Felipe Lessa wrote:
On 10/15/07, apfelmus [EMAIL PROTECTED] wrote:
lasts :: Int - [a] - [a]
lasts n xs = head $ [x | (x,[]) - zip (tails xs) (tails $ drop
n xs)]
(...)
main n = print . sum . map read . lasts n . lines = getContents
But that's a a
On Oct 15, 2007, at 9:48 , Brandon S. Allbery KF8NH wrote:
On Oct 15, 2007, at 7:02 , [EMAIL PROTECTED] wrote:
IO is different, you *cannot* make it non-monadic.
Not really true; it's just much more painful.
Expanding on this slightly: the neat thing about Haskell's monads is
not that
Claus Reinke [EMAIL PROTECTED] writes:
if this is the official interpretation of cabal package version numbers,
could it please be made explicit in a prominent position in the cabal docs?
Me too. This is not a criticism nor endorsement of any particular
scheme, just a vote in favor of having
Claus Reinke wrote:
Simon Marlow wrote:
Another reason not to change the name of 'base' is that there would be
a significant cost to doing so: the name is everywhere, not just in
the source code of GHC and its tools, but wiki pages, documentation,
and so on.
but the name that is everywhere
Hi, its Ryan here...
I've just come from an intensive course in java and have been thrown into the
imperative world of haskell.
The problem that I have is extremely simple in java but I am having trouble
adjusting my old mindset.
A multiset is a collection of items.
Each item may occur one
On Sun, Oct 14, 2007 at 11:54:54PM +0200, ntupel wrote:
On Sat, 2007-10-13 at 09:56 -0400, Brandon S. Allbery KF8NH wrote:
Now you need to start forcing things; given laziness, things tend to
only get forced when in IO, which leads to time being accounted to
the routine where the
Claus Reinke wrote:
if this is the official interpretation of cabal package version numbers,
could it please be made explicit in a prominent position in the cabal docs?
Yes - I think it would be a good idea to make that convention explicit
somewhere (I'm sure we've talked about it in the
Thanks for all the feedback. I removed GHC 6.4 and re-installed 6.6.1
and was able to install Haddock and other things in a few seconds. It
seems that the GOA and Lambdabot complicated the environment under the
hook, I will just leave them alone for now.
Life is too short (and haskell has enough
Ryan Bloor wrote:
Hi, its Ryan here...
I've just come from an intensive course in java and have been thrown
into the imperative world of haskell.
The problem that I have is extremely simple in java but I am having
trouble adjusting my old mindset.
A multiset is a collection of items.
Each
On Mon, Oct 15, 2007 at 03:49:44PM +0100, Ryan Bloor wrote:
Hi, its Ryan here...
I've just come from an intensive course in java and have been thrown into the
imperative world of haskell.
The problem that I have is extremely simple in java but I am having trouble
adjusting my old
On Mon, 15 Oct 2007, Ryan Bloor wrote:
Hi, its Ryan here...
I've just come from an intensive course in java and have been thrown into the
imperative world of haskell.
The problem that I have is extremely simple in java but I am having trouble
adjusting my old mindset.
A multiset is a
Magnus Therning wrote:
On the other hand Redmine does look cleaner somehow and I've never seen
a trac site that is as easy to find my way around as www.redmine.org.
That site loads slowly for me in Firefox (loading several files per
page, perhaps?). In some page's source on that site, it
Yes indeed, Concurrent Clean actually just passes around the world object
in direct/explicit style but uses uniquness typing to make sure nothing
happens that would violate the nice FP paradigm (mainly referential
transparency?). That is, I think it's like that :)
-Original Message-
From:
Peter Verswyvelen writes, about non-monadic IO, after the posting of
Brandon S. Allbery, who reacted to my claim that IO Monad is unavoidable:
Not really true; it's just much more painful. You just e.g.
explicitly do what the ghc library's implementation of IO does:
construct a chain of
Hi,
I'm pleased to announce the first external release of a set of
Haskell bindings for the Selenium automated web testing system
(specifically, the Selenium Remote Control). These bindings make it
possible to use Haskell to write test scripts that automatically
exercise arbitrary web
Peter Verswyvelen writes about non-monadic IO, unique external worlds:
But... isn't this what the Haskell compiler runtime do internally when
IO monads are executed? Passing the RealWorld singleton from action to
action?
I never looked into any Haskell compiler. Chalmers, or York, don't
[EMAIL PROTECTED] wrote:
Yes, *different approach*. So, there *are* differences. Compilers,
anyway,
are special applications. I wanted to see - responding to Brandon - a
normal Haskell program, which does IO without monads, that't all.
The problem is then when you hide something, you hide. It
And Haskell embedded a logical programming language on accident.
On 10/15/07, Manuel M T Chakravarty [EMAIL PROTECTED] wrote:
Dan Piponi wrote,
On 10/12/07, Brandon S. Allbery KF8NH [EMAIL PROTECTED] wrote:
He wants to write entire programs in the type system,
something like the crazies
I tried this library on Win32. A very nice initiative indeed.
Currently, I found the following problems:
- as mentioned in the WIN32 readme file, the library does not seem to
work with GHCI. Firstly, it seems to look for incorrect DLLs. When I
copy SDL.DLL to both SDLmain.DLL and SDL.DLL.DLL,
On Oct 15, 2007, at 13:32 , Peter Verswyvelen wrote:
[EMAIL PROTECTED] wrote:
Yes, *different approach*. So, there *are* differences.
Compilers, anyway,
are special applications. I wanted to see - responding to Brandon
- a
normal Haskell program, which does IO without monads, that't all.
[EMAIL PROTECTED] wrote:
Peter Verswyvelen writes about non-monadic IO, unique external worlds:
But... isn't this what the Haskell compiler runtime do internally
when IO monads are executed? Passing the RealWorld singleton from
action to action?
In GHC, yes.
I never looked into any
On Mon, 2007-10-15 at 10:48 -0400, David Roundy wrote:
I have no idea if this example will help your actual code, but it
illustrates that at least in this example, it's pretty easy to gain an
order of magnitude in speed. (That func is a weird function, by the
way.)
Thanks for your reply
You need a way to specify foo 1.2 foo 2, which is a
suggestion that was tossed around here recently.
but what does such a version range say? that i haven't tested any
versions outside the range (because they didn't exist when i wrote
my package)? or that i have, and know that later
but the name that is everywhere does not stand for what the new version
provides! any place that is currently referring to 'base' will have to be
inspected to check whether it will or will not work with the reduced
base package. and any place that is known to work with the new
base package
However, I'd like to separate it from Cabal. Cabal provides mechanism not
policy, regarding version numbers.
but the examples in the cabal docs should reflect the standard
interpretation of version numbers.
of course, i have absolutely no idea how to write stable packages under
this
Hi
is const = id?
const 'x' 'y'
'x'
id 'x'
'x'
Cheers,
Paul
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On 10/15/07, PR Stanley [EMAIL PROTECTED] wrote:
Hi
is const = id?
You answered the question yourself
const 'x' 'y'
'x'
id 'x'
'x'
const has another parameter. Their types are
id:: a - a
const :: a - b - a
HTH,
--
Felipe.
___
PR Stanley wrote:
is const = id?
No, const is saturated with 2 arguments, id with 1.
const 1 2 - 1
id 1 2 - type error
b
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Brandon S. Allbery KF8NH wrote:
On Oct 15, 2007, at 13:32 , Peter Verswyvelen wrote:
[EMAIL PROTECTED] wrote:
Yes, *different approach*. So, there *are* differences. Compilers,
anyway,
are special applications. I wanted to see - responding to Brandon - a
normal Haskell program, which
On Oct 15, 2007, at 19:00 , ChrisK wrote:
Brandon S. Allbery KF8NH wrote:
Use the source of unsafePerformIO as an example of how to write code
which passes around RealWorld explicitly, but without
unencapsulating it
like unsafePerformIO does.
The main problem here, I think, is that
I am trying to parse various date and time formats using the parseTime
function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me
trouble looks like this:
2008-06-26T11:00:00.000-07:00
Specifically, the time zone offset isn't covered by the format parameters
given. I can almost
http://alberrto.googlepages.com/easyvision
An experimental Haskell system for fast prototyping of computer vision
and image processing applications.
Looks ridiculously cool.
-- Don
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jgbailey:
I am trying to parse various date and time formats using the parseTime
function found in (GHC 6.6.1) Data.Time.Format. The one that is giving me
trouble looks like this:
2008-06-26T11:00:00.000-07:00
Specifically, the time zone offset isn't covered by the format
Lennart Augustsson wrote,
And Haskell embedded a logical programming language on accident.
Well, we are just trying to fix that :)
On 10/15/07, *Manuel M T Chakravarty* [EMAIL PROTECTED]
mailto:[EMAIL PROTECTED] wrote:
Dan Piponi wrote,
On 10/12/07, Brandon S. Allbery KF8NH
On 10/15/07, ChrisK [EMAIL PROTECTED] wrote:
Also you need to get you hand on State# RealWorld either
(1) Honestly, by wrapping your code in IO again and using it normally
(2) From a copy, via unsafeInterleaveIO
(3) From nowhere, via unsafePerformIO
Or you can get it honestly via lifting:
Oops, I read too fast, you mentioned that as #1.
On 10/15/07, ChrisK [EMAIL PROTECTED] wrote:
Also you need to get you hand on State# RealWorld either
(1) Honestly, by wrapping your code in IO again and using it normally
Silly me.
-- ryan
___
Hello,
In a Hugs environment, I am able to import System.Directory but not to
import System.Posix. Here is my environment ...
.;{Hugs}\packages\*;C:\ftp\CatTheory\Haskell\SOE\graphics\lib\win32\*. I
really want to use the Posix module. Help!!!
Kind regards, Bill Halchin
On Tuesday 16 October 2007 11:45, Claus Reinke wrote:
how about using a provides/expects system instead of betting on
version numbers? if a package X expects the functionality of base-1.0,
cabal would go looking not for packages that happen to share the name,
but for packages that provide
On Mon, Oct 15, 2007 at 10:57:48PM +0100, Claus Reinke wrote:
so i wonder why everyone else claims to be happy with the status quo?
We aren't happy with the status quo. Rather, we know that no matter how
much we do, the situation will never improve, so most of us have stopped
wasting out time.
stefanor:
On Mon, Oct 15, 2007 at 10:57:48PM +0100, Claus Reinke wrote:
so i wonder why everyone else claims to be happy with the status quo?
We aren't happy with the status quo. Rather, we know that no matter how
much we do, the situation will never improve, so most of us have stopped
All,
I've been casually developing a PacketBB (i.e. Generalized Manet Packet
Format) library in Haskell. I think I have a need to pass state
information as a phantom type - I'll step through the issue now.
With the 'AddressBlock' (S5.2.1 packetBB draft 8), network addresses are
abbreviated as
Hello,
I am fairly familiar with 1st order logic ... hence I think I
understand where Z (Zed) is going ... i.e.
http://en.wikipedia.org/wiki/Z_notation. It seems to be based on the ZFC
formal notion of set theory.
1) I have a formal spec in Z (Zed) and the implementation is in ANSI C. Can
I actually got this done several hours ago, but my DSL is being
annoying tonight...
Anyway, here's a simple example of how to do explicit/non-monadic I/O
in GHC. (It *only* works in GHC; other compilers have different
internal implementations of IO.) I specifically modeled it to
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