Re: [Haskell-cafe] [IO Int] - IO [Int]
Hoogle is also helpful http://haskell.org/hoogle/?q=%5Bm+a%5D+-%3E+m+%5Ba%5D 2007/5/4, Phlex [EMAIL PROTECTED]: Hello all, I'm trying to learn haskell, so here's is my first newbie question. I hope this list is appropriate for such help requests. I'm trying to write a function with the signature [IO Int] - IO [Int] Here is my first attempt : conv :: [IO Int] - IO [Int] conv l = do val - (head l) return (val : (conv (tail l))) This does not work as I'm consing an Int to an (IO [Int]). So I tried this : conv2 :: [IO Int] - IO [Int] conv2 l = do val - (head l) rest - (conv2 (tail l)) return (val : rest) That works, but it won't work for infinite lists. How could I achieve the desired result ? Thanks in advance, Sacha ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Debugging
On 5/5/07, Stefan O'Rear [EMAIL PROTECTED] wrote: On Fri, May 04, 2007 at 10:44:15PM -0700, Ryan Dickie wrote: I've only written trivial applications and functions in haskell. But the title of this thread got me thinking. In an imperative language you have clear steps, states, variables to watch, etc. What techniques/strategies might one use for a functional language? I personally most often use a divide-and-conquer approach. I pick a point about halfway down the call stack, and add trace calls. If the subproblems are handled correctly, narrow scope to higher levels; otherwise narrow to lower levels. Repeat until you have a single misbehaving function. Isn't that called binary search, instead of divide-and-conquer? BTW, how about adding assertion in Haskell? Can it be done? (I've searched in my GHC 6.4.2 library documentation, and can't find 'assert') Is there any way to automatically clean all the mess I've done in debugging/asserting (like removing all trace/assert expressions) when I compile Haskell source code? Or should I create a simple program to remove them? Stefan -- Demi masa.. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Debugging
monang: On 5/5/07, Stefan O'Rear [EMAIL PROTECTED] wrote: On Fri, May 04, 2007 at 10:44:15PM -0700, Ryan Dickie wrote: I've only written trivial applications and functions in haskell. But the title of this thread got me thinking. In an imperative language you have clear steps, states, variables to watch, etc. What techniques/strategies might one use for a functional language? I personally most often use a divide-and-conquer approach. I pick a point about halfway down the call stack, and add trace calls. If the subproblems are handled correctly, narrow scope to higher levels; otherwise narrow to lower levels. Repeat until you have a single misbehaving function. Isn't that called binary search, instead of divide-and-conquer? BTW, how about adding assertion in Haskell? Can it be done? (I've searched in my GHC 6.4.2 library documentation, and can't find 'assert') 'assert' is in Control.Exception. there's also a couple of 3rd party packages for assert-like behaviour: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/loch-0.2 http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Safe-0.1 Is there any way to automatically clean all the mess I've done in debugging/asserting (like removing all trace/assert expressions) when I compile Haskell source code? Or should I create a simple program to remove them? Using a logging/writer monad might be a nice approach. 'assert's are compiled out under -O, in G, too. -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Debugging
Sorry, replying myself. On 5/5/07, Monang Setyawan [EMAIL PROTECTED] wrote: BTW, how about adding assertion in Haskell? Can it be done? (I've searched in my GHC 6.4.2 library documentation, and can't find 'assert') This can be done using Assertions. Lines below are taken from the docs. Assertions assert :: Bool - a - a If the first argument evaluates to True, then the result is the second argument. Otherwise an AssertionFailed exception is raised, containing a String with the source file and line number of the call to assert. Assertions can normally be turned on or off with a compiler flag (for GHC, assertions are normally on unless optimisation is turned on with -O or the -fignore-asserts option is given). When assertions are turned off, the first argument to assert is ignored, and the second argument is returned as the result. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Detect Either Windows or Linux environment
On Fri, 2007-05-04 at 22:23 -0700, SevenThunders wrote: Prelude System.Info [os, arch] [darwin,powerpc] Thank you for your help. I somehow missed that when I was browsing through the library documentation. On windows, interestingly the os function returns mingw Yes, that's one of Neil's pet hates. It might change so something more obvious some time. Duncan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Monad definition question
Ilya Tsindlekht wrote: Does the definition of monad silently assume that if f and f' are equal in the sense that they return the same value for any argument o correct type then m = f = m = f' Of course NOT! Here's an example, in a State monad f x = put True f' x = put False Clearly, _by the definition above_, f and f' are the same -- for any argument of correct type, they return the same value, namely, (). However, if we perform the observation execState (return 'a' = f) True execState (return 'a' = f') True we quite clearly see the difference. Robin Green wrote: How could it be otherwise? How are you going to distinguish between f and f' if they are indistinguishable functions, in Haskell? Because f and f' are NOT referentially transparent functions. They are NOT pure functions, their application may have _an effect_. And comparing effectful computations is quite difficult. It's possible: I believe (bi)simulation is the best approach; there are other approaches. It may be useful to relate to imperative programming: m1 = (\x - m2) is let x = m1 in m2 Indeed, monadic 'bind' is *exactly* equivalent to 'let' of impure eager languages such as ML. The first monadic law return x = f === f x is trivial because in eager languages, any value (which is an effectful-free computation) is by default injected into the world of possibly effectful expressions: Any value is an expression. The second law m = (\x - return x) === m becomes let x = e in x === e and the third law (m1 = (\x - m2)) = (\y - m3) === m1 = (\x - m2 = \y - m3) provided x is not free in m3 becomes let y = (let x = m1 in m2) in m3 === let x = m1 in let y = m2 in m3 So, `bind' is `let' and monadic programming is equivalent to programming in the A-normal form. That is indeed all there is to monads. Here's the paragraph from the first page of Filinski's `Representing Monads' (POPL94) It is somewhat remarkable that monads have had no comparable impact on ``impure'' functional programming. Perhaps the main reason is that -- as clearly observed by Moggi, but perhaps not as widely appreciated in the ``purely functional'' community -- the monadic framework is already built into the semantic core of eager functional languages with effects, and need not be expressed explicitly. ``Impure'' constructs, both linguistic (e.g., updatable state, exceptions, or first-class continuations) and external to the language (I/O, OS interface, etc.), all obey a monadic discipline. The only aspect that would seem missing is the ability for programmers to use their own, application-specific monadic abstractions -- such as nondeterminism or parsers [31] -- with the same ease and naturality as built-in effects. Filinski then showed that the latter seemingly missing aspect indeed only appears to be missing. It is important to understand that once we come to monads, we lost referential transparency. Monadic code is more difficult to reason about -- as any imperative code. One often sees the slogan that Haskell is the best imperative language. And with monad, it is. One often forgets that 'best' here has the down-side. Haskell amplifies both advantages _and_ disadvantages of imperative programming. At least imperative programmers don't have to think about placing seq at the right place to make sure a file is read from before it is closed, and don't have to think about unsafeInterleaveIO. It seems the latter has become so indispensable that it is recommended to Haskell novices without a second thought. One may wonder if functional programming still matters. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] The Functional Pearls
I've created a wiki page collecting the 'functional pearl' papers that have appeared in JFP and ICFP and other places over the last 20 odd years. http://haskell.org/haskellwiki/Research_papers/Functional_pearls Lots of lovely functional programs there. There's also a list on that page of pearls that don't appear to be online. If you know where they live, please add the links! Cheers, Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Monad definition question
On Sat, May 05, 2007 at 12:09:03AM -0700, [EMAIL PROTECTED] wrote: Ilya Tsindlekht wrote: Does the definition of monad silently assume that if f and f' are equal in the sense that they return the same value for any argument o correct type then m = f = m = f' Of course NOT! Here's an example, in a State monad f x = put True f' x = put False Clearly, _by the definition above_, f and f' are the same -- for any argument of correct type, they return the same value, namely, They aren't - they return different values of type State Bool () (). However, if we perform the observation execState (return 'a' = f) True execState (return 'a' = f') True we quite clearly see the difference. Of course - because f 'a' and f' 'a' are different values. (return 'a' = f is by laws of monad the same as f 'a') Robin Green wrote: How could it be otherwise? How are you going to distinguish between f and f' if they are indistinguishable functions, in Haskell? Because f and f' are NOT referentially transparent functions. They are NOT pure functions, their application may have _an effect_. And They ARE pure functions (just as all Haskell functions) They return values of monad type. comparing effectful computations is quite difficult. It's possible: I believe (bi)simulation is the best approach; there are other approaches. It may be useful to relate to imperative programming: m1 = (\x - m2) is let x = m1 in m2 The analogy is not always straight-forward - try the list monad. Indeed, monadic 'bind' is *exactly* equivalent to 'let' of impure eager languages such as ML. The first monadic law return x = f === f x is trivial because in eager languages, any value (which is an effectful-free computation) is by default injected into the world of possibly effectful expressions: Any value is an expression. The second law m = (\x - return x) === m becomes let x = e in x === e and the third law (m1 = (\x - m2)) = (\y - m3) === m1 = (\x - m2 = \y - m3) provided x is not free in m3 becomes let y = (let x = m1 in m2) in m3 === let x = m1 in let y = m2 in m3 So, `bind' is `let' and monadic programming is equivalent to programming in the A-normal form. That is indeed all there is to monads. Here's the paragraph from the first page of Filinski's `Representing Monads' (POPL94) It is somewhat remarkable that monads have had no comparable impact on ``impure'' functional programming. Perhaps the main reason is that -- as clearly observed by Moggi, but perhaps not as widely appreciated in the ``purely functional'' community -- the monadic framework is already built into the semantic core of eager functional languages with effects, and need not be expressed explicitly. ``Impure'' constructs, both linguistic (e.g., updatable state, exceptions, or first-class continuations) and external to the language (I/O, OS interface, etc.), all obey a monadic discipline. The only aspect that would seem missing is the ability for programmers to use their own, application-specific monadic abstractions -- such as nondeterminism or parsers [31] -- with the same ease and naturality as built-in effects. Filinski then showed that the latter seemingly missing aspect indeed only appears to be missing. Would this require some kind of macros doing extensive pre-processing of the code? It is important to understand that once we come to monads, we lost referential transparency. Monadic code is more difficult to reason about -- as any imperative code. One often sees the slogan that Haskell is the best imperative language. And with monad, it is. One often forgets that 'best' here has the down-side. Haskell amplifies both advantages _and_ disadvantages of imperative programming. At least imperative programmers don't have to think about placing seq at the right place to make sure a file is read from before it is closed, and don't have to think about unsafeInterleaveIO. It seems the latter has become so indispensable that it is recommended to Haskell novices without a second thought. One may wonder if functional programming still matters. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Detect Either Windows or Linux environment
Hi Thank you for your help. I somehow missed that when I was browsing through the library documentation. On windows, interestingly the os function returns mingw Yes, that's one of Neil's pet hates. It might change so something more obvious some time. On Yhc the os function will return the name of the OS, on GHC and Hugs it returns mingw even if you are using the native WinHugs build done using Visual Studio and have never installed mingw... And its still one of my pet hates! Thanks Neil ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Monad definition question
Ilya Tsindlekht wrote It may be useful to relate to imperative programming: m1 = (\x - m2) is let x = m1 in m2 The analogy is not always straight-forward - try the list monad. This equivalence holds even for the List Monad. Here is an example of non-determinism: http://caml.inria.fr/pub/ml-archives/caml-list/2007/02/1d4df471019050b89e20a002303a8498.en.html and here's an excerpt from that message, showing lets (aka bind): let numbers = List.map (fun n - (fun () - n)) [1;2;3;4;5];; let pyth () = let (v1,v2,v3) = let i = amb numbers in let j = amb numbers in let k = amb numbers in if i*i + j*j = k*k then (i,j,k) else failwith too bad in Printf.printf got the result (%d,%d,%d)\n v1 v2 v3;; Here, 'amb' is like 'msum' and any error is mzero. If we replace 'let' with 'do', and '=' with '-' in some places, it looks almost like Haskell. Although the scheduler (the `run' function of the `monad') described in the message accumulates all possible worlds, it returns as soon as one `thread' made it successfully to the end. It is trivial to get the scheduler to run the remaining `treads' searching for more answers (by threads I certainly don't mean OS threads). The user code above stays as it is. The implementation of amb has been extended to annotate choices (and so possible worlds) with probabilities, which propagate in due course. The result not merely lists the answers but also their computed probabilities. Filinski then showed that the latter seemingly missing aspect indeed only appears to be missing. Would this require some kind of macros doing extensive pre-processing of the code? Hopefully the code above showed that no macros and no preprocessing required. In that code, addition, multiplication, if-then-else and all other OCaml operations remain as they have always been, with no modifications or redefinitions whatsoever. Delimited continuations suffice for everything, as Filinski proved in his paper. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The Functional Pearls
On 05/05/07, Donald Bruce Stewart [EMAIL PROTECTED] wrote: I've created a wiki page collecting the 'functional pearl' papers that have appeared in JFP and ICFP and other places over the last 20 odd years. http://haskell.org/haskellwiki/Research_papers/Functional_pearls Lots of lovely functional programs there. That's wonderful. I only recently found out about them and was blown away by the beauty of Richard Bird's sudoku solver. (The slides, anyway.) Let's go straight to the intravenous injection of awesome programs... D. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Detect Either Windows or Linux environment
Thank you for your help. I somehow missed that when I was browsing through the library documentation. On windows, interestingly the os function returns mingw Yes, that's one of Neil's pet hates. It might change so something more obvious some time. On Yhc the os function will return the name of the OS, on GHC and Hugs it returns mingw even if you are using the native WinHugs build done using Visual Studio and have never installed mingw... And its still one of my pet hates! Presumably GHC is compiled under mingw. (Personally I'm not a fan of having to use a UNIX emulator when you're actually in M$ Windoze, but never mind...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] An interesting toy
Greetings. I have something which you might find mildly interesting. (Please don't attempt the following unless you have some serious CPU power available, and several hundred MB of hard drive space free.) darcs get http://www.orphi.me.uk/darcs/Chaos cd Chaos ghc -O2 --make System1 ./System1 On my super-hyper-monster machine, the program takes an entire 15 minutes to run to completion. When it's done, you should have 500 images sitting in front of you. (They're in PPM format - hence the several hundred MB of disk space!) The images are the frames that make up an animation; if you can find a way to "play" this animation, you'll be treated to a truely psychedelic light show! (If not then you'll just have to admire them one at a time. The first few dozen frames are quite boring by the way...) If you want to, you can change the image size. For example, "./System1 800" will render at 800x800 pixels instead of the default 200x200. (Be prepaired for big slowdowns!) What is it? Well, it's a physical simulation of a "chaos pendulum". That is, a magnetic pendulum suspended over a set of magnets. The pendulum would just swing back and forth, but the magnets perturb its path in complex and unpredictable ways. However, rather than simulate just 1 pendulum, the program simulates 40,000 of them, all at once! For each pixel, a pendulum is initialised with a velocity of zero and an initial position corresponding to the pixel coordinates. As the pendulums swing, each pixel is coloured according to the proximity of the corresponding pendulum to the tree magnets. Help requested... Can anybody tell me how to make the program go faster? I already replaced all the lists with IOUArrays, which resulted in big, big speedups (and a large decrease in memory usage). But I don't know how to make it go any faster. I find it worrying that the process of converting pendulum positions to colours appears to take significantly longer than the much more complex task of performing the numerical integration to discover the new pendulum positions. Indeed, using GHC's profiling tools indicates that the most time is spent executing the function "quant8". This function is defined as: quant8 :: Double - Word8 quant8 = floor . (0xFF *) I can't begin to imagine how this can be the most compute-intensive part of the program when I've got all sorts of heavy metal maths going on with the numerical integration and so forth...! Anyway, if anybody can tell me how to make it run faster, I'd be most appriciative! Also, is there an easy way to make the program use both of the CPUs in my PC? (Given that the program maps two functions over two big IOUArrays...) Finally, if anybody has any random comments about the [lack of] qualify in my source code, feel free... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is Excel a FP language?
I just had a thought... Why doesn't somebody implement a spreadsheet where Haskell is the formula language? 8-) I have already been struggling (unsuccessfully) to write a program to graph functions, but why not go the whole hog and make an entire spreadsheet program? Possibly one of the most depressing things about Haskell is that there isn't one single large application anywhere that you can point to and say "this was made with Haskell". Maybe this could be that app? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is Excel a FP language?
andrewcoppin: I just had a thought... Why doesn't somebody implement a spreadsheet where Haskell is the formula language? 8-) I have already been struggling (unsuccessfully) to write a program to graph functions, but why not go the whole hog and make an entire spreadsheet program? Possibly one of the most depressing things about Haskell is that there isn't one single large application anywhere that you can point to and say this was made with Haskell. Maybe this could be that app? pugs? darcs? ghc? xmonad? (ok, not big) Lots on haskell.org to point to. pick your favourite one :-) -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is Excel a FP language?
On 05/05/07, Andrew Coppin [EMAIL PROTECTED] wrote: I just had a thought... Why doesn't somebody implement a spreadsheet where Haskell is the formula language? 8-) http://sigfpe.blogspot.com/2006/11/from-l-theorem-to-spreadsheet.html may interest. -- -David House, [EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is Excel a FP language?
I just had a thought... Why doesn't somebody implement a spreadsheet where Haskell is the formula language? 8-) http://sigfpe.blogspot.com/2006/11/from-l-theorem-to-spreadsheet.html may interest. ...ok, and now my head hurts... (Haskell seems to do that lots. I'm not sure why.) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] a question concerning type constructors
Hi all, In Haskell, is it possible to declare a type constructor with a variable number of type variables e.g. data Tuple * allowing the following declarations: t: Tuple u: Tuple Bool v: Tuple Bool Int w: Tuple Bool Int Char ? E. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] a question concerning type constructors
On Sat, May 05, 2007 at 02:26:45PM +0100, Eric wrote: Hi all, In Haskell, is it possible to declare a type constructor with a variable number of type variables e.g. data Tuple * allowing the following declarations: t: Tuple u: Tuple Bool v: Tuple Bool Int w: Tuple Bool Int Char No. (nor is it possible to be kind-polymorphic at all) Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] c2hs errors when compiling hsGnuTls
Hey there,
I'm getting the following errors when I try to compile hsGnuTls [1]:
~/hs/sandbox/hsgnutls $ c2hs --version
C-Haskell Compiler, version 0.14.5 Travelling Lightly, 12 Dec 2005
build platform is i486-pc-linux-gnu 1, True, True, 1
~/hs/sandbox/hsgnutls $ runhaskell Setup.lhs build
Setup.lhs: Warning: The field hs-source-dir is deprecated, please
use hs-source-dirs.
Preprocessing library hsgnutls-0.2.3...
c2hs: Error in C header file.
/usr/include/bits/pthreadtypes.h:69: (column 6) [FATAL]
Syntax error!
The symbol `;' does not fit here.
Setup.lhs: got error code while preprocessing: Network.GnuTLS.GnuTLS
c2hs version:
I've attached the file it references in case that's relevant. Any tips
on how I might address this?
Thanks in advance,
-David House, [EMAIL PROTECTED]
/* Copyright (C) 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _BITS_PTHREADTYPES_H
#define _BITS_PTHREADTYPES_H 1
#define __SIZEOF_PTHREAD_ATTR_T 36
#define __SIZEOF_PTHREAD_MUTEX_T 24
#define __SIZEOF_PTHREAD_MUTEXATTR_T 4
#define __SIZEOF_PTHREAD_COND_T 48
#define __SIZEOF_PTHREAD_COND_COMPAT_T 12
#define __SIZEOF_PTHREAD_CONDATTR_T 4
#define __SIZEOF_PTHREAD_RWLOCK_T 32
#define __SIZEOF_PTHREAD_RWLOCKATTR_T 8
#define __SIZEOF_PTHREAD_BARRIER_T 20
#define __SIZEOF_PTHREAD_BARRIERATTR_T 4
/* Thread identifiers. The structure of the attribute type is not
exposed on purpose. */
typedef unsigned long int pthread_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_ATTR_T];
long int __align;
} pthread_attr_t;
typedef struct __pthread_internal_slist
{
struct __pthread_internal_slist *__next;
} __pthread_slist_t;
/* Data structures for mutex handling. The structure of the attribute
type is not exposed on purpose. */
typedef union
{
struct __pthread_mutex_s
{
int __lock;
unsigned int __count;
int __owner;
/* KIND must stay at this position in the structure to maintain
binary compatibility. */
int __kind;
unsigned int __nusers;
__extension__ union
{
int __spins;
__pthread_slist_t __list;
};
} __data;
char __size[__SIZEOF_PTHREAD_MUTEX_T];
long int __align;
} pthread_mutex_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_MUTEXATTR_T];
long int __align;
} pthread_mutexattr_t;
/* Data structure for conditional variable handling. The structure of
the attribute type is not exposed on purpose. */
typedef union
{
struct
{
int __lock;
unsigned int __futex;
__extension__ unsigned long long int __total_seq;
__extension__ unsigned long long int __wakeup_seq;
__extension__ unsigned long long int __woken_seq;
void *__mutex;
unsigned int __nwaiters;
unsigned int __broadcast_seq;
} __data;
char __size[__SIZEOF_PTHREAD_COND_T];
__extension__ long long int __align;
} pthread_cond_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_CONDATTR_T];
long int __align;
} pthread_condattr_t;
/* Keys for thread-specific data */
typedef unsigned int pthread_key_t;
/* Once-only execution */
typedef int pthread_once_t;
#if defined __USE_UNIX98 || defined __USE_XOPEN2K
/* Data structure for read-write lock variable handling. The
structure of the attribute type is not exposed on purpose. */
typedef union
{
struct
{
int __lock;
unsigned int __nr_readers;
unsigned int __readers_wakeup;
unsigned int __writer_wakeup;
unsigned int __nr_readers_queued;
unsigned int __nr_writers_queued;
/* FLAGS must stay at this position in the structure to maintain
binary compatibility. */
unsigned int __flags;
int __writer;
} __data;
char __size[__SIZEOF_PTHREAD_RWLOCK_T];
long int __align;
} pthread_rwlock_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_RWLOCKATTR_T];
long int __align;
} pthread_rwlockattr_t;
#endif
#ifdef __USE_XOPEN2K
/* POSIX spinlock data type. */
typedef volatile int pthread_spinlock_t;
/* POSIX barriers data type. The structure of the type is
deliberately not exposed. */
typedef union
{
char __size[__SIZEOF_PTHREAD_BARRIER_T];
long int __align;
} pthread_barrier_t;
typedef union
{
char __size[__SIZEOF_PTHREAD_BARRIERATTR_T];
int
Re: [Haskell-cafe] a question concerning type constructors
I'm not sure what you want to accomplish, but if you like type hackery, this might be helpful: http://okmij.org/ftp/Haskell/types.html#polyvar-fn On 5/5/07, Eric [EMAIL PROTECTED] wrote: Hi all, In Haskell, is it possible to declare a type constructor with a variable number of type variables e.g. data Tuple * allowing the following declarations: t: Tuple u: Tuple Bool v: Tuple Bool Int w: Tuple Bool Int Char ? E. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Problems with Hs-Plugins
I tried following very simple program: module Main where import System.Eval.Haskell main = do i - eval 1 + 6 :: Int [] :: IO (Maybe Int) if isJust i then putStrLn (show (fromJust i)) else return () I compile it with ghc -c Main.hs and everything seems fine. When I run it with ghc Main.o I get following message: Main.o(.text+0x48):fake: undefined reference to `AltDataziTypeable_zdfTypeableInt_closure' Main.o(.text+0x4d):fake: undefined reference to `SystemziEvalziHaskell_eval_closure' Main.o(.text+0x36f):fake: undefined reference to `__stginit_SystemziEvalziHaskell_' Main.o(.rodata+0x0):fake: undefined reference to `SystemziEvalziHaskell_eval_closure' Main.o(.rodata+0x4):fake: undefined reference to `AltDataziTypeable_zdfTypeableInt_closure' collect2: ld returned 1 exit status When I run it with runhaskell Main I get: GHCi runtime linker: fatal error: I found a duplicate definition for symbol _GHCziWord_fromEnum1_closure whilst processing object file c:/ghc/ghc-6-4-2/ghc-6.4.2/HSbase1.o This could be caused by: * Loading two different object files which export the same symbol * Specifying the same object file twice on the GHCi command line * An incorrect `package.conf' entry, causing some object to be loaded twice. GHCi cannot safely continue in this situation. Exiting now. Sorry. So I did probably something totally wrong, but what? ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Problems with Hs-Plugins
pvolgger: I tried following very simple program: module Main where import System.Eval.Haskell main = do i - eval 1 + 6 :: Int [] :: IO (Maybe Int) if isJust i then putStrLn (show (fromJust i)) else return () I compile it with ghc -c Main.hs and everything seems fine. When I run it with ghc Main.o I get following message: Main.o(.text+0x48):fake: undefined reference to `AltDataziTypeable_zdfTypeableInt_closure' Main.o(.text+0x4d):fake: undefined reference to `SystemziEvalziHaskell_eval_closure' Main.o(.text+0x36f):fake: undefined reference to `__stginit_SystemziEvalziHaskell_' Main.o(.rodata+0x0):fake: undefined reference to `SystemziEvalziHaskell_eval_closure' Main.o(.rodata+0x4):fake: undefined reference to `AltDataziTypeable_zdfTypeableInt_closure' collect2: ld returned 1 exit status You'll need to use --make to link aginst the 'plugins' package. As in: ghc --make Main.hs When I run it with runhaskell Main I get: Won't work on windows. You're trying to dynamically link the dynamic linker, when using 'runhaskell'. (this is ok on ELF systems). -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: Displaying infered type signature of 'offside' functions
Simon Peyton-Jones [EMAIL PROTECTED] wrote: Hi, The principal difficulties here are to do with what do we want rather the implementation challenges. yes, I thought that too (I mean a haskell compiler have to deal with 'the' wanted information already for typechecking purposes etc.). 1. Should the compiler print the type of every declaration? With -tdump-types, yes. Should GHCi allow you to ask the type of a local decl? Yes. 2. How should the variables be identified? There may be many local bindings for 'f', so you can't say just :t f. Ditto if dumping all local bindings. Well, for where-bound ones at least I would consider something like :t f$g$h or :t f.g.h as a useable command to identify this h: f ... = .. where g ... = ... where h ... = ... If the hierachy is not unique, :t could print all matches, and if the user wants to be more specific, he could issue something like :t f#2.h for the last h in someting something like f ... = ... where h ... = ... f ... = ... where h .. = ... Well, something like :t f.g.* would be nice, too, where * works like in 'pattern globbing' (i.e. matching all decls local to f.g). 3. Do you want all locally-bound variables (including those bound by lambda or case), or just letrec/where bound ones? I think 'all', myself, but there are a lot of them. I just thought about where/let bound ones. But I am not sure ;) 4. (This is the trickiest one.) The type of a function may mention type variables bound further out. Consider f :: [a] - Int f xs = let v = head xs in ... Have to think about it. These are all user-interface issues. If some people would like to thrash out a design, and put it on the Wiki, I think there is a good chance that someone (possibly even me) would implement it. Sounds great! I will wait a few days, if someone extends this thread and then put the ideas from this thread on a wiki-page and post the link (if not someone else do it first). Best regards Georg Sauthoff ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The Functional Pearls
ithika: On 05/05/07, Donald Bruce Stewart [EMAIL PROTECTED] wrote: I've created a wiki page collecting the 'functional pearl' papers that have appeared in JFP and ICFP and other places over the last 20 odd years. http://haskell.org/haskellwiki/Research_papers/Functional_pearls Lots of lovely functional programs there. That's wonderful. I only recently found out about them and was blown away by the beauty of Richard Bird's sudoku solver. (The slides, anyway.) Let's go straight to the intravenous injection of awesome programs... D. Great. It was an idea that came up in #haskell this morning: 19:43:28 geezusfreeek any good articles/tutorials/whatever about how to best go about actually designing a program in haskell (or functional languages in general)? 19:48:09 geezusfreeek i have a mostly OO background, and i want to avoid tainting my functional prog ramming experience with the OO design patterns and habits i have 19:48:31 geezusfreeek and it's already clear to me that most of my habits are going to lead me straight to confusion 19:54:48 dons geezusfreeek: possibly some of the functional pearl, and design-ish, papers from ICFP would be a good read 19:55:10 dons basically replacing going to oxford or chalmers, and having Richard Bird teach you how to think like a lambda :-) So, what better way to steep yourself in the design cult(ure) of the lambda, than to go through the pearls. :-) -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: The Functional Pearls
[EMAIL PROTECTED] (Donald Bruce Stewart) writes: I've created a wiki page collecting the 'functional pearl' papers that have appeared in JFP and ICFP and other places over the last 20 odd years. http://haskell.org/haskellwiki/Research_papers/Functional_pearls Lots of lovely functional programs there. There's also a list on that page of pearls that don't appear to be online. If you know where they live, please add the links! The ones that appear in JFP are on line... in some sense... it's just they want money for looking at them. I don't suppose we could somehow persuade CUP to make them freely accessible after a year or two? -- Jón Fairbairn [EMAIL PROTECTED] ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] The Functional Pearls
Donald Bruce Stewart wrote: So, what better way to steep yourself in the design cult(ure) of the lambda, than to go through the pearls. :-) Is there a black perl available? Oh... damn... Sorry about that. God I can't wait for that film to be released! _ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Re: The Functional Pearls
jon.fairbairn: [EMAIL PROTECTED] (Donald Bruce Stewart) writes: I've created a wiki page collecting the 'functional pearl' papers that have appeared in JFP and ICFP and other places over the last 20 odd years. http://haskell.org/haskellwiki/Research_papers/Functional_pearls Lots of lovely functional programs there. There's also a list on that page of pearls that don't appear to be online. If you know where they live, please add the links! The ones that appear in JFP are on line... in some sense... it's just they want money for looking at them. I don't suppose we could somehow persuade CUP to make them freely accessible after a year or two? I found that the vast majority are in fact online via the author's websites. And in fact, JFP seems to have free access (temporary?) for the Jan 07 JFP (only). Yes, it really does seem a shame not to have access to the back issues, nor to work of authors who don't put their journal articles online. I want to read Bird's sudoku solver! -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
Sounds like a neat program. I'm on a laptop right now but i'll check it out later. The reason I am mailling is because you can use mencoder to convert a stream of image files into a video file. http://www.mplayerhq.hu/DOCS/HTML/en/menc-feat-enc-images.html --ryan On 5/5/07, Andrew Coppin [EMAIL PROTECTED] wrote: Greetings. I have something which you might find mildly interesting. (Please don't attempt the following unless you have some serious CPU power available, and several hundred MB of hard drive space free.) darcs get http://www.orphi.me.uk/darcs/Chaos cd Chaos ghc -O2 --make System1 ./System1 On my super-hyper-monster machine, the program takes an entire 15 minutes to run to completion. When it's done, you should have 500 images sitting in front of you. (They're in PPM format - hence the several hundred MB of disk space!) The images are the frames that make up an animation; if you can find a way to play this animation, you'll be treated to a truely psychedelic light show! (If not then you'll just have to admire them one at a time. The first few dozen frames are quite boring by the way...) If you want to, you can change the image size. For example, ./System1 800 will render at 800x800 pixels instead of the default 200x200. (Be prepaired for *big* slowdowns!) *What is it?* Well, it's a physical simulation of a chaos pendulum. That is, a magnetic pendulum suspended over a set of magnets. The pendulum would just swing back and forth, but the magnets perturb its path in complex and unpredictable ways. However, rather than simulate just 1 pendulum, the program simulates 40,000 of them, all at once! For each pixel, a pendulum is initialised with a velocity of zero and an initial position corresponding to the pixel coordinates. As the pendulums swing, each pixel is coloured according to the proximity of the corresponding pendulum to the tree magnets. *Help requested...* Can anybody tell me how to make the program go faster? I already replaced all the lists with IOUArrays, which resulted in big, big speedups (and a large decrease in memory usage). But I don't know how to make it go any faster. I find it worrying that the process of converting pendulum positions to colours appears to take significantly longer than the much more complex task of performing the numerical integration to discover the new pendulum positions. Indeed, using GHC's profiling tools indicates that the most time is spent executing the function quant8. This function is defined as: quant8 :: Double - Word8 quant8 = floor . (0xFF *) I can't begin to *imagine* how *this* can be the most compute-intensive part of the program when I've got all sorts of heavy metal maths going on with the numerical integration and so forth...! Anyway, if anybody can tell me how to make it run faster, I'd be most appriciative! Also, is there an easy way to make the program use *both* of the CPUs in my PC? (Given that the program maps two functions over two big IOUArrays...) Finally, if anybody has any random comments about the [lack of] qualify in my source code, feel free... ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
Ryan Dickie wrote: Sounds like a neat program. I'm on a laptop right now but i'll check it out later. The reason I am mailling is because you can use mencoder to convert a stream of image files into a video file. Indeed, it is pretty neat. I'd post an image, but I'm not sure whether the other people on this list would appriciate a binary attachment. I'm hoping to make a DVD of various simulations - but that's kind of difficult when rendering full-size animations takes many hours! _ Hence the request for optimisation help... ;-) Mencoder works on Linux, IrfanView + VirtualDub does it nicely on Windoze, I'm sure MacOS has something that can stitch PPM images together too. Use whatever you have on your platform. :-D ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
On Sat, May 05, 2007 at 09:17:50PM +0100, Andrew Coppin wrote: Ryan Dickie wrote: Sounds like a neat program. I'm on a laptop right now but i'll check it out later. The reason I am mailling is because you can use mencoder to convert a stream of image files into a video file. Indeed, it is pretty neat. I'd post an image, but I'm not sure whether the other people on this list would appriciate a binary attachment. I'm AFAIK, nobody cares about binaryness per se. It's merely the fact that images tend to be rather large... Is it =50kb? (typical maximum size of a 1-line patch that has been bloated by darcs' ultra low density context format) hoping to make a DVD of various simulations - but that's kind of difficult when rendering full-size animations takes many hours! _ Hence the request for optimisation help... ;-) Mencoder works on Linux, IrfanView + VirtualDub does it nicely on Windoze, I'm sure MacOS has something that can stitch PPM images together too. Use whatever you have on your platform. :-D I've had success with ffmpeg years ago (linux) Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
Andrew Coppin wrote: Greetings. I have something which you might find mildly interesting. (Please don't attempt the following unless you have some serious CPU power available, and several hundred MB of hard drive space free.) darcs get http://www.orphi.me.uk/darcs/Chaos cd Chaos ghc -O2 --make System1 ./System1 On my super-hyper-monster machine, the program takes an entire 15 minutes to run to completion. When it's done, you should have 500 images sitting in front of you. (They're in PPM format - hence the several hundred MB of disk space!) The images are the frames that make up an animation; if you can find a way to play this animation, you'll be treated to a truely psychedelic light show! (If not then you'll just have to admire them one at a time. The first few dozen frames are quite boring by the way...) If you want to, you can change the image size. For example, ./System1 800 will render at 800x800 pixels instead of the default 200x200. (Be prepaired for /big/ slowdowns!) *What is it?* Well, it's a physical simulation of a chaos pendulum. That is, a magnetic pendulum suspended over a set of magnets. The pendulum would just swing back and forth, but the magnets perturb its path in complex and unpredictable ways. However, rather than simulate just 1 pendulum, the program simulates 40,000 of them, all at once! For each pixel, a pendulum is initialised with a velocity of zero and an initial position corresponding to the pixel coordinates. As the pendulums swing, each pixel is coloured according to the proximity of the corresponding pendulum to the tree magnets. *Help requested...* Can anybody tell me how to make the program go faster? I already replaced all the lists with IOUArrays, which resulted in big, big speedups (and a large decrease in memory usage). But I don't know how to make it go any faster. I find it worrying that the process of converting pendulum positions to colours appears to take significantly longer than the much more complex task of performing the numerical integration to discover the new pendulum positions. Indeed, using GHC's profiling tools indicates that the most time is spent executing the function quant8. This function is defined as: quant8 :: Double - Word8 quant8 = floor . (0xFF *) I can't begin to /imagine/ how /this/ can be the most compute-intensive part of the program when I've got all sorts of heavy metal maths going on with the numerical integration and so forth...! Anyway, if anybody can tell me how to make it run faster, I'd be most appriciative! Also, is there an easy way to make the program use /both/ of the CPUs in my PC? (Given that the program maps two functions over two big IOUArrays...) Finally, if anybody has any random comments about the [lack of] qualify in my source code, feel free... Try adding strictness annotations to all the components of all your data structures (i.e. put a ! before the type). Not all of the need it, but I doubt any need to be lazy either. Probably the reason quant8 seems to be taking so much time is that it is where a lot of stuff finally gets forced. Certainly, for things that are primitive like Colour and Vector you want the components to be strict, in general. I did this for the program and ran System1 100 and it took maybe a couple of minutes, it seemed to be going at a decent clip. 200x200 should take 4 times longer, I assume, and I still don't see that taking 15 minutes. This is on a laptop running on a Mobile AMD Sempron 3500+. Also, you have many many superfluous parentheses and use a different naming convention from representative Haskell code (namely camelCase). ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Is Excel a FP language?
I just had a thought... Why doesn't somebody implement a spreadsheet where Haskell is the formula language? 8-) http://sigfpe.blogspot.com/2006/11/from-l-theorem-to-spreadsheet.html may interest. ...ok, and now my head hurts... (Haskell seems to do that lots. I'm not sure why.) Well, check out http://www.mrtc.mdh.se/index.php?choice=projectsid=0041 This might ease the headache a little. It is basically the result of a MSc thesis project that a student did for me a couple of years ago. Björn Lisper PS. Also check out http://www.cs.kent.ac.uk/projects/vital/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
On Sat, May 05, 2007 at 03:33:03PM -0500, Derek Elkins wrote: Try adding strictness annotations to all the components of all your data structures (i.e. put a ! before the type). Not all of the need it, but I doubt any need to be lazy either. Probably the reason quant8 seems to be taking so much time is that it is where a lot of stuff finally gets forced. Certainly, for things that are primitive like Colour and Vector you want the components to be strict, in general. (In theory at least) That would not be an issue at all - the GHC profiler uses lexical, *not dynamic*, call stacks. I did this for the program and ran System1 100 and it took maybe a couple of minutes, it seemed to be going at a decent clip. 200x200 should take 4 times longer, I assume, and I still don't see that taking 15 minutes. This is on a laptop running on a Mobile AMD Sempron 3500+. Also, you have many many superfluous parentheses and use a different naming convention from representative Haskell code (namely camelCase). Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
Try adding strictness annotations to all the components of all your data structures (i.e. put a ! before the type). Not all of the need it, but I doubt any need to be lazy either. Probably the reason quant8 seems to be taking so much time is that it is where a lot of stuff finally gets forced. Certainly, for things that are primitive like Colour and Vector you want the components to be strict, in general. Yes, originally the profile was showing quant8 taking something absurd like 80% of the CPU time. When I changed the framebuffer to an IOUArray, the time spent in quant8 dropped *drastically*. (Because now the framebuffer is strict, and that's forcing the evaluation sooner.) I could certainly try making vectors, colours and arrays strict and see if that does something... (Thinking about it, the colour computation has a square root in it, and I bet that doesn't get forced until it hits quant8... Square root is an expensive operation on currentl hardware isn't it?) Also, you have many many superfluous parentheses and use a different naming convention from representative Haskell code (namely camelCase). This is a pet hate of mine. NamesLikeThis are fine. names_like_this are fine too. But for the love of God, namesLikeThis just looks stupid and annoying! So I generally use camel case for stuff which has to start uppercase, and underscores for stuff that has to start lowercase. It's a system, and it works. Unfortunately it's not the standard convention in Haskell. (And I doubt I will convince anybody to change it...) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] An interesting toy
Try adding strictness annotations to all the components of all your data structures (i.e. put a ! before the type). Not all of the need it, but I doubt any need to be lazy either. Probably the reason quant8 seems to be taking so much time is that it is where a lot of stuff finally gets forced. Certainly, for things that are primitive like Colour and Vector you want the components to be strict, in general. I just did that. Gives a few percent speed increase. (Turns out on my machine System1 with default options actually takes 5 minutes, not 15. And with the extra strictness, it completes about 40 seconds faster. So not a vast speedup - but worth having!) Also tried playing with GHC options. I found the following: -fexcess-precision: No measurable effect. -funbox-strict-fields: Roughly 40 seconds faster again. -fno-state-hack: Makes the program somewhat *slower*. -funfolding-update-in-place: No measurable effect. Hmm, I suppose if I get *really* desperate, I could always try compiling with GHC 6.6.1 instead of 6.6... ;-) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Re: (Chaos) [An interesting toy]
Andrew Coppin shares with us his Chaos program. I confirm that on my HP laptop it was faster than 15 minutes, but I won't speculate how to optimize it. I appreciated the elegance of overloading, the usage of Num classes, etc, which makes it more readable, although somewhat slower. Actually it took slightly less than 10 minutes for 300x300. I wonder whether making some constants global (such as dt) would change anything. For those who don't have patience to execute the program, I converted the ppms to a XVID coded AVI file. Thanks, Andrew http://users.info.unicaen.fr/~karczma/Work/Chaos0.avi What I didn't appreciate was the use of simple extrapolating Euler's method which for oscillating systems is known to be unstable, so the results of the simulation may be far from the reality. Well, one chaos is worth another one, and the sin is not as mortal as in the case of truly periodic systems, but it may be the cause that it is difficult to see the classical fractal structure of the attraction domains on the generated images. Try to use leapfrog Verlet... It will require to keep not only p and v for each frame, but also the acceleration, but the corrections are minor. Of course it will be slower, but then, why not increase dt? Jerzy Karczmarczuk ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Any Haskellers in St Louis, MO?
Hi there.. Are there any Haskellers in St Louis , MO? Is there an active group here? Want to start one? Thanks... Deech _ Exercise your brain! Try Flexicon. http://games.msn.com/en/flexicon/default.htm?icid=flexicon_hmemailtaglineapril07 ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Any Haskellers anywhere? (was Re: Any Haskellers in St Louis, MO?)
Maybe we could use a page on the wiki to note who'd be interested in meeting up and where they all live? -- Mark ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere? (was Re: Any Haskellers in St Louis, MO?)
Sounds like a good idea to me. I'd like to see if any Haskellers are in Madison. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere?
Am 06.05.2007 um 03:52 schrieb Rob Hoelz: Sounds like a good idea to me. I'd like to see if any Haskellers are in Madison. Doesn't Google have a service for visualizing locations on a map? The wiki could point there, for example... Gabor ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere?
Gabor Greif [EMAIL PROTECTED] wrote: Am 06.05.2007 um 03:52 schrieb Rob Hoelz: Sounds like a good idea to me. I'd like to see if any Haskellers are in Madison. Doesn't Google have a service for visualizing locations on a map? The wiki could point there, for example... Gabor I bet Google does have one, but first thing that came to my mind is Frappr: http://www.frappr.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere?
hoelz: Gabor Greif [EMAIL PROTECTED] wrote: Am 06.05.2007 um 03:52 schrieb Rob Hoelz: Sounds like a good idea to me. I'd like to see if any Haskellers are in Madison. Doesn't Google have a service for visualizing locations on a map? The wiki could point there, for example... Gabor I bet Google does have one, but first thing that came to my mind is Frappr: http://www.frappr.com/ We have an old map of irc user locations, here, you could start with that: http://haskell.org/hawiki/HaskellUserLocations -- Don ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere? (was Re: Any Haskellers in St Louis, MO?)
http://www.haskell.org/hawiki/HaskellUserLocations On 5/5/07, Mark T.B. Carroll [EMAIL PROTECTED] wrote: Maybe we could use a page on the wiki to note who'd be interested in meeting up and where they all live? -- Mark ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ricardo Guimarães Herrmann You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete - R. Buckminster Fuller ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Any Haskellers anywhere?
Try this ... Google Maps - My Maps - Haskellers http://maps.google.com/maps/ms?f=qhl=ent=kie=UTF8om=1msa=0ll=-23.553838,-46.656811spn=0.004386,0.006738z=18 On 5/5/07, Rob Hoelz [EMAIL PROTECTED] wrote: Gabor Greif [EMAIL PROTECTED] wrote: Am 06.05.2007 um 03:52 schrieb Rob Hoelz: Sounds like a good idea to me. I'd like to see if any Haskellers are in Madison. Doesn't Google have a service for visualizing locations on a map? The wiki could point there, for example... Gabor I bet Google does have one, but first thing that came to my mind is Frappr: http://www.frappr.com/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe -- Ricardo Guimarães Herrmann You never change things by fighting the existing reality. To change something, build a new model that makes the existing model obsolete - R. Buckminster Fuller ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
