Re: [Haskell-cafe] diff implementation in haskell

2009-12-07 Thread Ketil Malde
Don Stewart d...@galois.com writes: Are there pure haskell implementations of diff and diff3 algorithms? http://hackage.haskell.org/package/Diff Wherein we can read: | This is an implementation of the O(ND) diff algorithm [...]. It is O(mn) | in space. At first I thought 'N' and 'M'

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Ketil Malde
Lyndon Maydwell maydw...@gmail.com writes: On Mon, Dec 7, 2009 at 2:43 PM, Colin Adams colinpaulad...@googlemail.com wrote: 2009/12/7 drostin77 ml.nwgr...@gmail.com: Hello Hopefully Helpful Haskell Community! (I really wanted that to be alliteration... couldn't come up with an h word

Re: [Haskell-cafe] diff implementation in haskell

2009-12-07 Thread Don Stewart
ketil: Don Stewart d...@galois.com writes: Are there pure haskell implementations of diff and diff3 algorithms? http://hackage.haskell.org/package/Diff Wherein we can read: | This is an implementation of the O(ND) diff algorithm [...]. It is O(mn) | in space. At first I

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread drostin77
I take 'Hood. Er... any responses to my questions? Ketil Malde-5 wrote: Lyndon Maydwell maydw...@gmail.com writes: On Mon, Dec 7, 2009 at 2:43 PM, Colin Adams colinpaulad...@googlemail.com wrote: 2009/12/7 drostin77 ml.nwgr...@gmail.com: Hello Hopefully Helpful Haskell Community!

RE: [Haskell-cafe] When are undecidables ok?

2009-12-07 Thread Simon Peyton-Jones
I don’t think it’s all that complicated or fragile. To resolve the constraint (C T1 T2), use the appropriate instance declaration to express it in terms of (hopefully simpler) constraints. Keep doing that. If you terminate, GHC should. Example: to resolve Eq [Int], use the instance

Re: [Haskell-cafe] diff implementation in haskell

2009-12-07 Thread Erik de Castro Lopo
Don Stewart wrote: This looks like the paper, http://www.xmailserver.org/diff2.pdf Page 2, The algorithm can be refined to use linear space, N and M appear to be the length of the sequences, D is the size of the minimum edit script. T'would be lovely to have that in the docs for the

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Lyndon Maydwell
I had heard that Hoogle actually compiled any type-signatures, where as Hayoo just did a text comparison. I'm not actually sure if this is true or not though. If it is, it would mean that [q] - [r] - [(q,r)] would return zip in Hoogle, but not Hayoo. Am I right about this? On Mon, Dec 7, 2009

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Roel van Dijk
On Mon, Dec 7, 2009 at 10:24 AM, Lyndon Maydwell maydw...@gmail.com wrote: I had heard that Hoogle actually compiled any type-signatures, where as Hayoo just did a text comparison. I'm not actually sure if this is true or not though. If it is, it would mean that [q] - [r] - [(q,r)] would

Re: [Haskell-cafe] Insert a laziness break into strict ST

2009-12-07 Thread Henning Thielemann
On Sun, 6 Dec 2009, Antoine Latter wrote: On Sun, Dec 6, 2009 at 5:46 PM, Henning Thielemann I hoped to get the first answer also for the second command. It seems that conversion from lazy to strict ST also removes laziness breaks. It seems that I have to stick to unsafeInterleaveIO, but I

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Timo B. Hübel
On Monday 07 December 2009 10:24:37 Lyndon Maydwell wrote: I had heard that Hoogle actually compiled any type-signatures, where as Hayoo just did a text comparison. I'm not actually sure if this is true or not though. If it is, it would mean that [q] - [r] - [(q,r)] would return zip in

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread Henning Thielemann
klondike schrieb: Henning Thielemann escribió: It seems again to me, that mixing of (programming) errors and exceptions is going on, and I assumed that the purpose of control-monad-exception is to separate them in a better way. You know, could you tell me when using head on an empty list is

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread Henning Thielemann
klondike schrieb: Now comes the time when I have to show you that not every exception could be handled, IE a file not found exception when looking for the config file can be fatal and force the program to stop. But what if this is on a library? How do you suggest that the programmer knows

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread Gregory Crosswhite
Ah, I had been meaning to read your article, so I appreciate you posting the link to it a second time. :-) Out of curiosity, how would you classify an error that results from a perfectly fine program, but ill-formed user input, such as when compiling a source file? Cheers, Greg On Dec 7,

[Haskell-cafe] Re: Do you need Windows USB in Haskell?

2009-12-07 Thread Maurí­cio CA
I don't need usb and I can't say I'm a windows user, but I'd be glad to test it since I have it on a virtual machine. In my case, installation fails on bindings-common. bindings-common fails on windows due to an old version of C library with GHC's windows version of gcc. Current version of

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread Henning Thielemann
Gregory Crosswhite schrieb: Ah, I had been meaning to read your article, so I appreciate you posting the link to it a second time. :-) Out of curiosity, how would you classify an error that results from a perfectly fine program, but ill-formed user input, such as when compiling a source

Re: [Haskell-cafe] OpenCL target for DPH?

2009-12-07 Thread Olex P
Hi, Good question. I'd like to know the answer too. Cheers, Alex. On Mon, Dec 7, 2009 at 4:10 AM, Marcus G. Daniels mdani...@lanl.gov wrote: Hi, I'm wondering if anyone has looked at OpenCL as target for Data Parallel Haskell? Specifically, having Haskell generate CL kernels, i.e. SIMD

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
Michael Snoyman schrieb: On Mon, Dec 7, 2009 at 5:30 AM, Ben Franksen ben.frank...@online.de mailto:ben.frank...@online.de wrote: Michael Snoyman wrote: On the other hand, what's so bad about treating errors as exceptions? If instead of the program crashing on an

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Neil Mitchell
Hi, It probably helps to know some of the history, as it explains a lot of what you see today. Hoogle was written first (about 5 years ago now), before there was hackage (so it doesn't search hackage), and with an emphasis on type search (as that's cool). Hayoo came a lot later (about 2 years ago

Re: [Haskell-cafe] Hoogle Down

2009-12-07 Thread Neil Mitchell
Hi Elliot, It is the right place, and Hoogle is now back up. Unfortunately the server it was run was out of disk space, which caused Hoogle to fail. Hopefully it won't happen again. Thanks, Neil 2009/11/29 Elliot Wolk elliot.w...@gmail.com: hello! im not sure that this is the correct mailing

[Haskell-cafe] Re: computing lists of pairs

2009-12-07 Thread Christian Maeder
Thanks again for your patience with me, your answers to this list (and the beginners list) are in general a real pleasure! Christian Daniel Fischer schrieb: Am Freitag 04 Dezember 2009 19:00:33 schrieb Christian Maeder: aP1 [] = [[]] aP1 (h:t) = do x - h xs - aP1 t return

[Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread John Lato
To reply to an earlier point of Andrew's (I can't find the quote now, sorry), one of the biggest difficulties developers face on Windows is the lack of common install locations/practices. Windows software is usually distributed as a binary, which may or may not include header files. These files

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread Ivan Lazar Miljenovic
Neil Mitchell ndmitch...@gmail.com writes: but if you use Hayoo for some reason other than Hoogle not searching all packages, I'd love to know. Isn't it obvious? We all use Hayoo for the Web 2.0 interface! :p /me is just kidding -- Ivan Lazar Miljenovic ivan.miljeno...@gmail.com

Re: [Haskell-cafe] SYB looping very, very mysteriously

2009-12-07 Thread David Fox
On Sat, Dec 5, 2009 at 2:38 AM, Andrea Vezzosi sanzhi...@gmail.com wrote: On Fri, Dec 4, 2009 at 8:51 PM, Jeremy Shaw jer...@n-heptane.com wrote: I have stripped things down to the bare minimum, and test under GHC 6.10, GHC 6.12, Linux, and Mac OS X. Results are consistent. In the following

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread klondike
Henning Thielemann escribió: A library function that reads a config file may declare to be able to throw the exception File not found, or it may introduce a new exception Could not read Config file with an extra field for the reason, why the file could not be read. This way you can construct a

[Haskell-cafe] Re: ANNOUNCE: PortAudio Windows Tutorial and Binaries

2009-12-07 Thread John Van Enk
Very cool. On Sun, Dec 6, 2009 at 7:29 PM, M Xyz functionallyharmoni...@yahoo.comwrote: I got a lot of great help this weekend from Haskell-Cafe, thanks. Now that I have portaudio up and running I put up a tutorial and a 103 kb download of all the windows binaries and files. I hope this

[Haskell-cafe] Is it possible: Haskell platform - portable edition

2009-12-07 Thread Rafael Gustavo da Cunha Pereira Pinto
Hello, Has anyone considered the possibility of making a *Portable* Haskell Platform distribution (portable meaning on a USB stick) for Windows? This worked form me: I installed GHC on one machine, copied it to a USB stick and created a batch to set the environment path and open a command

[Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread L.Guo
Hi there: My friend asked me a question, and i suppose he has found a bug of `groupBy'. Here is the code piece: List.groupBy (\a b - Foreign.unsafePerformIO (Text.Printf.printf \t%d = %d ?: %s\n a b (show (a=b)) return (a=b))) [7,3,5,9,6,8,3,5,4] I have tested it in GHC 6.10.4 (Win XP) and

Re: [Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread Stephen Tetley
Could it not be a bug in a) printf b) unsafePerformIO c) d) return e) = f) show g) GHC or GHCi? All of the above? Best wishes Stephen 2009/12/7 L.Guo leaveye@gmail.com: Hi there: My friend asked me a question, and i suppose he has found a bug of `groupBy'. Here is the code piece:

Re[2]: [Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread Bulat Ziganshin
Hello Stephen, Monday, December 7, 2009, 8:11:01 PM, you wrote: it's just what goupBy compares with the first element of group rather than comparing two adjancent elements. look at the trace it's not a bug, but misunderstanding of specification :) Could it not be a bug in a) printf b)

Re: [Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread Brent Yorgey
On Tue, Dec 08, 2009 at 12:45:59AM +0800, L.Guo wrote: Hi there: My friend asked me a question, and i suppose he has found a bug of `groupBy'. Here is the code piece: List.groupBy (\a b - Foreign.unsafePerformIO (Text.Printf.printf \t%d = %d ?: %s\n a b (show (a=b)) return (a=b)))

[Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Don Stewart
The Haskell Web News is a monthly summary of the hottest news about the Haskell programming language, as found in our online communities. If you want to catch up with what’s been happening in Haskell, this might be the journal for you.

Re: [Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread Matthijs Kooijman
Hi, I have tested it in GHC 6.10.4 (Win XP) and GHC 6.8.3 (Linux), both give the wrong result (categaried): 7 = 3 ?: False 3 = 5 ?: True 3 = 9 ?: True 3 = 6 ?: True 3 = 8 ?: True 3 = 3 ?: True 3 = 5 ?: True 3 = 4 ?: True

Re: [Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Deniz Dogan
2009/12/7 Don Stewart d...@galois.com: The Haskell Web News is a monthly summary of the hottest news about the Haskell programming language, as found in our online communities. If you want to catch up with what’s been happening in Haskell, this might be the journal for you.    

Re: [Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Tom Tobin
On Mon, Dec 7, 2009 at 11:25 AM, Deniz Dogan deniz.a.m.do...@gmail.com wrote: 2009/12/7 Don Stewart d...@galois.com: The Haskell Web News is a monthly summary of the hottest news about the Haskell programming language, as found in our online communities. If you want to catch up with what’s

Re: [Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Don Stewart
Deniz: I think the correct URL should be: Oops, well spotted. The original link will work now. http://haskellwebnews.wordpress.com/2009/12/05/whats-new-in-haskell-december-2009/ ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org

Re: [Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Deniz Dogan
2009/12/7 Tom Tobin korp...@korpios.com: On Mon, Dec 7, 2009 at 11:25 AM, Deniz Dogan deniz.a.m.do...@gmail.com wrote: 2009/12/7 Don Stewart d...@galois.com: The Haskell Web News is a monthly summary of the hottest news about the Haskell programming language, as found in our online

Re: [Haskell-cafe] The Haskell Web News: December 2009 Edition

2009-12-07 Thread Bulat Ziganshin
Hello Don, Monday, December 7, 2009, 8:16:25 PM, you wrote: http://haskellwebnews.wordpress.com/2009/12/05/whats-new-in-haskell-december-2009/ can we make download counts for individual packages available? my own program (http://freearc.org) has about 10k downloads/month so i doubt what place

Re: [Haskell-cafe] A bug of groupBy implement

2009-12-07 Thread Stephen Tetley
Hi L.Guo Brent has replied with the right answer. The definition of groupBy is below - the span in the where clause only compares with the first element of the current sub-list: -- | The 'groupBy' function is the non-overloaded version of 'group'. groupBy :: (a - a - Bool) - [a]

[Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Maurí­cio CA
To reply to an earlier point of Andrew's (I can't find the quote now, sorry), one of the biggest difficulties developers face on Windows is the lack of common install locations/practices. Windows software is usually distributed as a binary, which may or may not include header files. These

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Michael Snoyman
On Mon, Dec 7, 2009 at 2:13 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: Michael Snoyman schrieb: On Mon, Dec 7, 2009 at 5:30 AM, Ben Franksen ben.frank...@online.de mailto:ben.frank...@online.de wrote: Michael Snoyman wrote: On the other hand, what's so

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Mon, 7 Dec 2009, Michael Snoyman wrote: The only opinion I've stated so far is that it's ridiculous to constantly demand that people follow your definition of error vs exception, since the line is incredibly blurry and it buys you very little. If you have an example that is not contained

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Michael Snoyman
On Mon, Dec 7, 2009 at 9:07 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: On Mon, 7 Dec 2009, Michael Snoyman wrote: The only opinion I've stated so far is that it's ridiculous to constantly demand that people follow your definition of error vs exception, since the line is

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
I turn it around: give me an example where it's better for the runtime to exit than for some type of exception to be thrown, and *I'll* think about it ;). If you would have read my article, you had one ... ___ Haskell-Cafe mailing list

[Haskell-cafe] Re: Are there standard idioms for lazy, pure error handling?

2009-12-07 Thread Henning Thielemann
Somehow I missed this thread. I want to say that I have implemented a general way to add the information of an exception to the end of an arbitrary data structure. http://hackage.haskell.org/packages/archive/explicit-exception/0.1.4/doc/html/Control-Monad-Exception-Asynchronous.html Duncan

[Haskell-cafe] Re: Are there standard idioms for lazy, pure error handling?

2009-12-07 Thread Henning Thielemann
@Apfelmus: For practical purposes I think Train should have swapped type parameters in order to make Functor act on the type of the list elements. data Train b a = Wagon a (Train b a) | Loco b ___ Haskell-Cafe mailing list

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Mon, 7 Dec 2009, Michael Snoyman wrote: I actually *did* read your article, and don't know what you are referring to. If this is true, sorry, I didn't had the impression. I also think that in an earlier mail I answered, that errors can leave you with corrupt data, say invalid file

Re: [Haskell-cafe] Re: Are there standard idioms for lazy, pure error handling?

2009-12-07 Thread Nicolas Pouillard
Excerpts from Henning Thielemann's message of Mon Dec 07 20:36:27 +0100 2009: @Apfelmus: For practical purposes I think Train should have swapped type parameters in order to make Functor act on the type of the list elements. data Train b a = Wagon a (Train b a) | Loco

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Michael Snoyman
On Mon, Dec 7, 2009 at 9:53 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: On Mon, 7 Dec 2009, Michael Snoyman wrote: I actually *did* read your article, and don't know what you are referring to. If this is true, sorry, I didn't had the impression. I also think that in an

Re: [Haskell-cafe] Re: [Haskell] ANNOUNCE: control-monad-exception 0.5 with monadic call traces

2009-12-07 Thread Jason Dusek
2009/12/07 klondike klondikehaskellc...@xiscosoft.es: Well I got used to going back to the previous state without crashing when I got a precondition violation due to user input. Though I assume that was asking a bit too much of Haskell. It's too much to ask of partial functions. If you want

[Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Frank Buss
Anyone interested in writing some lines of Haskell code for generating the Zumkeller numbers? http://www.luschny.de/math/seq/ZumkellerNumbers.html My C/C# solutions looks clumsy (but is fast). I think this can be done much more elegant in Haskell with lazy evaluation. Not related to Haskell,

Re: [Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Andrew Coppin
Jeffrey Scofield wrote: I think the real cultural difference is that you aren't a user, you're a prospective Haskell developer, as others have said. Developers pretty much have to install tools (like compilers and preprocessors) and have to work with source code. And I have no problem with

[Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Andrew Coppin
John Lato wrote: To reply to an earlier point of Andrew's (I can't find the quote now, sorry), one of the biggest difficulties developers face on Windows is the lack of common install locations/practices. Windows software is usually distributed as a binary, which may or may not include header

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Joe Fredette
Here's a completely naive implementation, it's slow as cold molasses going uphill during a blizzard, but it doesn't seem to be wrong. I let it run in the interpreter for the last 3 minutes or so and it's reproduced the given list up to 126 (and hasn't crapped out yet). I imagine there's

Re: [Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Erik de Castro Lopo
Andrew Coppin wrote: Well, I don't know. It's going to vary from package to package, but most things that have a semi-official Windows version either come as a Windows Installer package (which, one presumes records where it put everything *somewhere* in the Windows registry) Is that done

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Henning Thielemann
On Mon, 7 Dec 2009, Frank Buss wrote: Anyone interested in writing some lines of Haskell code for generating the Zumkeller numbers? http://www.luschny.de/math/seq/ZumkellerNumbers.html My C/C# solutions looks clumsy (but is fast). I think this can be done much more elegant in Haskell with

Re: [Haskell-cafe] Is anyone reading Pattern Calculus by Barry Jay?

2009-12-07 Thread Duane Johnson
Thanks Bernie, I've applied for membership in the forum. I'm grateful that technology can connect me with so distant but interesting a group! Duane On Dec 7, 2009, at 12:41 AM, Bernie Pope florbit...@gmail.com wrote: 2009/12/7 Duane Johnson duane.john...@gmail.com: I just bought a copy of

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Richard O'Keefe
When I was working at Quintus, I came up with a classification which I can simplify something like this: operating system fault Something bad happened (like a remote node going down) that was entirely out of your control. There is nothing you can do to your program to

Re: [Haskell-cafe] OpenCL target for DPH?

2009-12-07 Thread Manuel M T Chakravarty
Marcus Daniels wrote, I'm wondering if anyone has looked at OpenCL as target for Data Parallel Haskell? Specifically, having Haskell generate CL kernels, i.e. SIMD vector type aware C language backend, as opposed to just a Haskell language binding. The short answer is that there is currently

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Daniel Fischer
Am Montag 07 Dezember 2009 22:33:32 schrieb Frank Buss: Anyone interested in writing some lines of Haskell code for generating the Zumkeller numbers? http://www.luschny.de/math/seq/ZumkellerNumbers.html My C/C# solutions looks clumsy (but is fast). I think this can be done much more elegant

[Haskell-cafe] SmallCheck design question

2009-12-07 Thread Johannes Waldmann
referring to the Serial instances in http://hackage.haskell.org/package/smallcheck : the idea is that series d gives all objects of depth = d. depth of a term from an algebraic data type is the standard depth concept for trees (maximum nesting of constructors = longest path from root to node)

[Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Ben Franksen
Michael Snoyman wrote: On Mon, Dec 7, 2009 at 9:53 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: On Mon, 7 Dec 2009, Michael Snoyman wrote: I also think that in an earlier mail I answered, that errors can leave you with corrupt data, say invalid file handles, memory pointers,

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Tue, 8 Dec 2009, Richard O'Keefe wrote: When I was working at Quintus, I came up with a classification which I can simplify something like this: It's certainly possible to classify errors and exceptions in other (also more fine grained) ways ... operating system fault

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Richard O'Keefe
On Dec 8, 2009, at 10:33 AM, Frank Buss wrote: Anyone interested in writing some lines of Haskell code for generating the Zumkeller numbers? http://www.luschny.de/math/seq/ZumkellerNumbers.html These lines of Haskell code find the Zumkeller numbers up to 5000 in 5 seconds on a 2.2GHz

Re: [Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Robert Greayer
On Mon, Dec 7, 2009 at 4:37 PM, Andrew Coppin andrewcop...@btinternet.comwrote: And I have no problem with needing to install a Haskell compiler. If I had to install a seperate C compiler to make FFI to C work, that wouldn't seem unreasonable either. (As it happens, GHC has a C backend, so

RE: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Frank Buss
From: daniel.is.fisc...@web.de [mailto:daniel.is.fisc...@web.de] Not related to Haskell, but do you think semi-Zumkeller numbers are semi-perfect numbers? The site you linked to says so. I've not investigated. Peter Luschny posted the link in a discussion in a German newsgroup:

RE: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Frank Buss
From: Richard O'Keefe [mailto:o...@cs.otago.ac.nz] These lines of Haskell code find the Zumkeller numbers up to 5000 in 5 seconds on a 2.2GHz intel Mac. The equivalent in SML took 1.1 seconds. Note that this just finds whether a suitable partition exists; it does not report the partition.

Re: [Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Richard O'Keefe
On Dec 8, 2009, at 11:00 AM, Andrew Coppin wrote: In other words, Windows needs to become just like Unix. Not going to happen. I have the use of a dual-boot MacOS/Vista laptop. Subsystem for Unix-based applications is a Microsoft download. It means I can compile C programs using 'cc' or

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Richard O'Keefe
On Dec 8, 2009, at 12:28 PM, Henning Thielemann wrote: representation faults your program tried to do something meaningful but the system was unable to represent the result (integer overflow, upper case of ÿ in a Latin 1 system, floating point overflow on a

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Tue, 8 Dec 2009, Ben Franksen wrote: Michael, Henning There are two meanings to the word 'exception' in this context; both of you tend to conflate these different meanings. One meaning is about a *mechanism* for non-local control flow; the other is about certain classes of un-desired

Re: [Haskell-cafe] Re: binding to C libraries on Windoww

2009-12-07 Thread Erik de Castro Lopo
Robert Greayer wrote: It helps, I believe, if you stop thinking of MinGW with MSYS as 'a pseudo-Unix system'. They're billed as the minimal toolset required on windows to use the GNU compilers and build system (and, as everybody knows, Gnu's not Unix). The great thing about these compilers

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Henning Thielemann
On Tue, 8 Dec 2009, Richard O'Keefe wrote: is_Zumkeller :: Int - Bool is_Zumkeller n = let facs = factors n fsum = sum facs in mod fsum 2 == 0 I see this test is essential. I didn't do it and thus my program did not find that 1800 is not a Zumkeller number within an hour. With

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Tue, 8 Dec 2009, Richard O'Keefe wrote: X/0, sqrt(-1), head [] are errors It depends on WHERE THE DATA CAME FROM. If your program actually computes X/0 or sqrt(-1) or head [] your program is buggy, independent from where the zero, the minus one or the empty list comes. Sure, the

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Henning Thielemann
On Tue, 8 Dec 2009, Richard O'Keefe wrote: On Dec 8, 2009, at 12:28 PM, Henning Thielemann wrote: It is the responsibility of the programmer to choose number types that are appropriate for the application. If I address pixels on a todays screen I will have to choose at least Word16. On

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread ajb
G'day all. Quoting Richard O'Keefe o...@cs.otago.ac.nz: These lines of Haskell code find the Zumkeller numbers up to 5000 in 5 seconds on a 2.2GHz intel Mac. The equivalent in SML took 1.1 seconds. Note that this just finds whether a suitable partition exists; it does not report the

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Richard O'Keefe
On Dec 8, 2009, at 1:27 PM, Henning Thielemann wrote: On Tue, 8 Dec 2009, Richard O'Keefe wrote: On Dec 8, 2009, at 12:28 PM, Henning Thielemann wrote: It is the responsibility of the programmer to choose number types that are appropriate for the application. If I address pixels on a

Re: [Haskell-cafe] Hayoo and Hoogle (beginner question)

2009-12-07 Thread drostin77
Thanks for all the answers, in particular the history (quoted) was informative! So for now the answer is indeed probably to use both, starting with Hoogle if I am searching by type. And if you do find that old hayoo command line search script yes please :P (esp the offline one, I do so much

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Daniel Fischer
Am Dienstag 08 Dezember 2009 01:54:12 schrieb a...@spamcop.net: G'day all. Quoting Richard O'Keefe o...@cs.otago.ac.nz: These lines of Haskell code find the Zumkeller numbers up to 5000 in 5 seconds on a 2.2GHz intel Mac. The equivalent in SML took 1.1 seconds. Note that this just finds

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Donn Cave
I'm wondering, what are we talking about here? - the meaning of error and exception? - personal responsibility when writing programs? - language features - library functions, runtime implementation etc.? The first two, I think could serve as the basis for an entertaining discussion. Where

[Haskell-cafe] How to deal with C buf in Haskell?

2009-12-07 Thread Magicloud Magiclouds
Hi, I am warping some C libs. In one function, I do this: 183 allocaBytes bufLen $ \buf - do 184ret - {# call buf_read #} 185 bluh 186 bala 187 buf 188 bufLen 189if ret 0 190 then userError bufRead error 191 else -- what should I do here? I am thinking

Re: [Haskell-cafe] How to deal with C buf in Haskell?

2009-12-07 Thread Bas van Dijk
On Tue, Dec 8, 2009 at 3:22 AM, Magicloud Magiclouds magicloud.magiclo...@gmail.com wrote: Hi,  I am warping some C libs. In one function, I do this: 183  allocaBytes bufLen $ \buf - do 184    ret - {# call buf_read #} 185      bluh 186      bala 187      buf 188      bufLen 189    if ret

[Haskell-cafe] Handles with their IOMode in their type

2009-12-07 Thread Bas van Dijk
Could not get to sleep tonight so I got up and hacked this together: http://hpaste.org/fastcgi/hpaste.fcgi/view?id=13782 Does something like this already exist on hackage: If not, I may turn this into a package and upload it tomorrow. Comments, criticism and patches are welcome. regards, Bas

Re: [Haskell-cafe] Re: Are there standard idioms for lazy, pure error handling?

2009-12-07 Thread wren ng thornton
Nicolas Pouillard wrote: Excerpts from Henning Thielemann's message of Mon Dec 07 20:36:27 +0100 2009: @Apfelmus: For practical purposes I think Train should have swapped type parameters in order to make Functor act on the type of the list elements. data Train b a = Wagon a (Train b a)

Re: [Haskell-cafe] ANN: hakyll-0.1

2009-12-07 Thread Tom Tobin
On Sat, Dec 5, 2009 at 6:35 AM, Jasper van der Jeugt jasper...@gmail.com wrote: Hakyll is a simple static site generator library, mostly aimed at blogs. It supports markdown, tex and html templates. It is inspired by the ruby Jekyll program. It has a very small codebase because it makes

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Michael Snoyman
On Tue, Dec 8, 2009 at 1:25 AM, Ben Franksen ben.frank...@online.de wrote: Michael Snoyman wrote: On Mon, Dec 7, 2009 at 9:53 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: On Mon, 7 Dec 2009, Michael Snoyman wrote: I also think that in an earlier mail I answered, that

[Haskell-cafe] Lots of Haskell at PEPM 2010 - Call for Participation

2009-12-07 Thread Janis Voigtländer
Hi all, If you are planning to go to Madrid in January, for POPL, don't forget registering for PEPM as well! If you haven't yet been planning to go, maybe you want to reconsider, for PEPM if not for POPL. Why, you ask? Well, the PEPM program has *lots* of Haskell this year. Indeed, no fewer

Re: [Haskell-cafe] Re: New Hackage category: Error Handling

2009-12-07 Thread Michael Snoyman
On Tue, Dec 8, 2009 at 7:40 AM, Michael Snoyman mich...@snoyman.com wrote: On Tue, Dec 8, 2009 at 1:25 AM, Ben Franksen ben.frank...@online.dewrote: Michael Snoyman wrote: On Mon, Dec 7, 2009 at 9:53 PM, Henning Thielemann lemm...@henning-thielemann.de wrote: On Mon, 7 Dec 2009,

Re: [Haskell-cafe] ANN: hakyll-0.1

2009-12-07 Thread Jasper Van der Jeugt
Okay, You're right. I will change the license info as soon as possible. Kind regards, Jasper Van der Jeugt On Dec 8, 2009 6:30 AM, Tom Tobin korp...@korpios.com wrote: On Sat, Dec 5, 2009 at 6:35 AM, Jasper van der Jeugt jasper...@gmail.com wrote: Hakyll is a simp... I hate to say this, but

Re: [Haskell-cafe] ANN: hakyll-0.1

2009-12-07 Thread Erik de Castro Lopo
Tom Tobin wrote: I hate to say this, but it looks like you're violating the GPL by not releasing Hakyll under the GPL, since Pandoc is GPL'd. Not necessarily. The 3 clause BSD license is officially a GPL compatible license. See:

Re: [Haskell-cafe] Zumkeller numbers

2009-12-07 Thread Ketil Malde
Richard O'Keefe o...@cs.otago.ac.nz writes: factors n = [m | m - [1..n], mod n m == 0] -- saves about 10% time, seems to give the same result: factors n = [m | m - [1..n `div` 2], mod n m == 0]++[n] (But checking against primes is even faster, it seems) -k -- If I haven't seen further,