Re: [Haskell-cafe] Specify array or list size?

with matrices... -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Re: Speed comparison?

On Wed, May 04, 2005 at 07:20:20PM +, Aaron Denney wrote: On 2005-05-03, David Roundy [EMAIL PROTECTED] wrote: An interesting challenge would be to rewrite fftw in haskell, and see how close one could come to the performance of the original... :) What precisely do you mean

Re: [Haskell-cafe] invalid character encoding

of which uses a different encoding for the filenames. In the case of removable media, this scenario isn't even unlikely. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell

Re: [Haskell-cafe] module Crypt_Discordian - code critique requested

it. Isn't it guaranteed unbreakable simply because there's no way to decrypt it? Since there isn't a one-to-one mapping of cyphertext to plaintext, I don't think it's actually a form of encryption. Basically it's the same as the sort function, which is also not invertible. -- David Roundy http

[Haskell-cafe] [darcs #222] performance problem with massive changes in a single file

I'm cc'ing haskell-cafe on this darcs bug, since I imagine there might be a student (or professor) hanging around there who might be interested in the implementation of an efficient LCS algorithm in haskell. [markjugg - Sun Feb 20 09:15:57 2005]: Typically in software, 1000's of line aren't

Re: [Haskell-cafe] What is MonadPlus good for?

monad. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] What is MonadPlus good for?

locking that it couldn't have been read between the original m and the later mzero. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] MonadPlus instance for IO

foobar) Any idea what I'm doing wrong? I'm using $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.2.2 packaged for debian. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http

Re: [Haskell-cafe] The Nature of Char and String

the Char as an eight bit C character, the only difference is that if it's opened as text on windows, your newlines get mangled. (...or treated properly, depending on your opinion.) -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe

Re: [Haskell-cafe] File path programme

On Sun, Jan 30, 2005 at 09:25:00PM +0100, Marcin 'Qrczak' Kowalczyk wrote: David Roundy [EMAIL PROTECTED] writes: No, it's not Unix-specific, it's portable. If you want to write portable C code, you have to use the standard library, which means that file names are represented as Ptr CChar

Re: [Haskell-cafe] File path programme

to convert between FilePath and CString. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] File path programme

painful would it be for the System.IO functions to have types such as readFile :: FilePath a = a - String ? -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] File path programme

(instead, it sees if they exist by trying to compile with them), so this constraint isn't necesary for *all* ghc users. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo

Re: [Haskell-cafe] File path programme

/. are also the same. The exception of course is that /foo and ./foo are not the same thing. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Re: Hugsvs GHC (again)was: Re: Somerandomnewbiequestions

which block needs to be read into memory... Wouldn't select always fail, since the block would never be read into memory until you call read? -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org

Re: [Haskell-cafe] Signature of a function

half the time, whereas the signatures are guaranteed by the compiler to be correct. One of the great things about haskell is how expressive the signatures tend to be... although that could just be an illusion due to the fact that I code am now a better coder than I used to be. -- David Roundy http

Re: [Haskell-cafe] Re: Hugs vs GHC (again) was: Re: Some random newbiequestions

what we need is a binary IO system first, and then the character-based IO can do whatever it likes without breaking things (since it'll only be used by programs that actually want unicode coding). -- David Roundy http://www.darcs.net ___ Haskell-Cafe

Re: [Haskell-cafe] Some random newbie questions

failures all the time? ghc does give warnings when pattern matches aren't exhaustive, at least when called with the compile flags used with darcs. It seems that you may be interested in the -fwarn-incomplete-patterns compile flag with ghc. -- David Roundy http://civet.berkeley.edu/droundy

Re: [Haskell-cafe] ReadS with Maybe

number of read values which is confusing and unsafe in my opinion. Isn't that because there could be more than one way to read the string? For example, in theory reads of an int from 123 might return [(123,), (12,3), (1,23)] -- David Roundy http://www.darcs.net

Re: [Haskell-cafe] GUI

it is stable in the sense that it doesn't crash. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Seeking comments on this IO proposal

... -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] FFI woes!

it gets garbage collected. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] FFI woes!

playing which would be ideal. Indeed. -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] numerical subtyping

for this are in the attached library. Alternatively, you could just use atan or erfc to map between the complete set of real numbers and the range from 0 to 1. This sort of trick is sometimes helpful to convert a constrained minimization into an unconstrained one. -- David Roundy http

Re: [Haskell-cafe] Re: Top Level TWI's again was Re: [Haskell] Re: Parameterized Show

, there are any that actually perform IO). -- David Roundy http://www.darcs.net ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Re: Top Level TWI's again was Re: [Haskell] Re: Parameterized Show

On Tue, Nov 23, 2004 at 01:51:24PM +, Keean Schupke wrote: David Roundy wrote: There are plenty of non-IO reasons to use unsafePerformIO, for which it is essential. If you want to write haskell code that uses a pointer (allocated possibly via an FFI C routine), it has to be in the IO

Re: [Haskell-cafe] Re: Pure Haskell Printf

the author of the format string less control over the formatting of particular types like numbers. It seems to me that control over formatting of numbers is the only reason to use anything printf-like... but perhaps that's just because of the frequency with which I print (and read) doubles. -- David

[Haskell-cafe] mkEmptyWeakPtr?

effectively has a Nothing value type. I suppose one could also make it a Weak (Maybe a), but in any case, I'd rather be able to just initialize the IORef to an empty weak pointer, so there wouldn't need to be any extra code when reading the value. -- David Roundy http://www.abridgegame.org

Re: [Haskell-cafe] Rethinking OO idioms

. Of course, you could also define a writeConfig :: FilePath - Config - IO () but then a user of your class could accidentally overwrite a change, if you had two parts of the code which read the same config, each made separate changes, and then each wrote their separate changes. -- David Roundy

Re: [Haskell-cafe] Writing binary files?

. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] cost of List.// for Ord types?

question: can you write a separate version of a function for the case where its argument is within a more specific class? -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

[Haskell-cafe] Functor instance for weak pointers?

= unsafePerformIO $ do ma - deRefWeak wa case ma of Nothing - return emptyWeak Just b - mkWeakPtr (f b) Nothing -- David Roundy http://www.abridgegame.org

Re: [Haskell-cafe] exceptions vs. Either

error message, so I use fail and error raw to indicate actual user errors. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Toy application advice wanted

, since wc -l would be something like a two-liner... -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Audio signal processing in Haskell

in haskell. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] looking for optimization advice

isn't an option. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] looking for optimization advice

...) -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

[Haskell-cafe] looking for optimization advice

compile this with -O -funbox-strict-fields, so the packed string contents are unboxed, if that makes any difference. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] looking for optimization advice

On Thu, Mar 25, 2004 at 11:39:26AM -0800, Carl Witty wrote: On Thu, 2004-03-25 at 10:09, David Roundy wrote: The function is a simple packed string compare, and I basically just call the C standard library function memcmp for this. Without further ado: I don't know how to make your

Re: [Haskell-cafe] loop in C , recursion in haskell

% 1; part_stack :: [Int] part_stack = [0,50] Note that I've performed a memoization optimization--this makes the code both smaller, faster and easier to read! :P But seriously, the C code doesn't do anything. Why do you want to translate it? (Unless it's homework...) -- David Roundy http

[Haskell-cafe] infix naming

, if you don't think of it as (is_less_than a) b, one might naturally think that (is_less_than a b) should be (a b). -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell

[Haskell-cafe] setPermissions bug?

setPermissions f (p {writeable = True}) should make the file world-writeable or just user-writeable. I don't know about that. But at a minimum, it should preserve world-readability. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing

Re: [Haskell-cafe] setPermissions bug?

(fileStatus, fileMode, setFileMode etc.). Well, in my case all I want to do is to copy permissions from one file to another, so get/setPermissions would have been fine. But yeah, I've already switched to using setFileMode etc. -- David Roundy http://www.abridgegame.org

Re: [Haskell-cafe] Producing fortran/C code with haskell?

] + g[i], if_ a $ doexp out[i][j][k] += x, if_ b $ doexp out[i][j][k] /= y[i][j][k] ] There are also features relating to expressions, which can simplify arithmetic for cases where a variable is known to be one or zero. But in general, it's an ugly piece of code... -- David Roundy http

Re: looking for data structure advice

result) using f = a `or_maybe` b `or_maybe` c -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

looking for data structure advice

want to do. :( -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Why are strings linked lists?

the standard system calls used by getCurrentDirectory etc accept CStrings). -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: There is flexible exception handling in Haskell?

, then the prelude catch will catch them, which is more likely what you want. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: what's the deal with user error on fail?

it, rather than user error, which makes them wonder if they did something wrong. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

what's the deal with user error on fail?

userErrors at the top level and failing with my own error message? -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Treating POSIX signals as exceptions?

On Tue, Nov 11, 2003 at 04:49:29PM +0100, Marcin 'Qrczak' Kowalczyk wrote: On, 10-11-2003, at 16:41, David Roundy wrote: I was wondering why System.Posix.Signals is as it is, and whether it could be rewritten to use exceptions, which seems like the obvious way to handle signals. I don't

Treating POSIX signals as exceptions?

. Is there a problem with this idea? -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Heap profiling in GHC broken?

make problems, +RTS -p works fine. I get a message meaning the equivalent of statement in '0x0058db43' points to memory in '0xfffc'. Could not read.) I believe this bug is fixed in CVS, so you could get it there or wait for 6.2. (I didn't fix it, I just reported it.) -- David Roundy http

Re: hSetBuffering stdin NoBuffering messes up terminal

-type programs to be written, as long as you don't also call hSetBuffering on the same Handle. Yay! That seems like precisely the right thing to do. :) -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED

Re: replacing guile with haskell?

On Fri, Oct 17, 2003 at 06:17:00PM -0400, Isaac Jones wrote: David Roundy [EMAIL PROTECTED] writes: Do you want to embed Haskell code or to embed a Haskell interpreter? I actually would like to embed a Haskell interpreter. (snip) H. I may be able to get by without calling

replacing guile with haskell?

support 64 bit platforms. Is there a solution to these problems, or will I be stuck with thousands of parentheses in my input file? -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org

Re: hSetBuffering stdin NoBuffering messes up terminal

of misinformation. It seems that as long as you set stdin's buffering back to LineBuffering before you exit, you are safe from messing up the terminal settings. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http

Re: replacing guile with haskell?

, before I can seriously consider starting work on a haskell interface. -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

how is Haskell pronounced?

, as in rascal or tattle. I feel silly telling people what a great language it is, when I can't even pronounce its name... :) -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman

Re: swap leak problem

even on small test runs (rather than my monster run that kills swap on my machine), so if you want a test case I can pretty easily get it for you. Although it won't be a small amount of code, it at least wouldn't require 200M of data. -- David Roundy http://www.abridgegame.org

swap leak problem

at a loss as to how to track this problem down, so any advise would be appreciated. -- David Roundy http://www.abridgegame.org/darcs ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

zlib binding providing Handle to compressed file.

, but such is life. Anyhow in case anyone is interested, I'm attaching the code. It creates a pipe using pipe(2) and spawns a thread to pass the data between the pipe and gzread or gzwrite. It's not pretty, but it's better than any other solution I could think of. Suggestions or criticisms are welcome. -- David

Re: haskell html-colorizer

On Wed, Sep 03, 2003 at 02:28:18PM -, [EMAIL PROTECTED] wrote: Are anyone aware of a haskell html-colorizer a' la the emacs-mode? I've never used it, but webcpp may be what you're looking for. http://webcpp.sourceforge.net/ -- David Roundy http://civet.berkeley.edu/droundy

Re: Haskell 6.0 install

and 5 can be installed in parallel without problems, and if you're writing pure haskell 98 with no extensions (as I imagine the book does), you should be able to use either one with no problems. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe

Re: Debugging

will depend on the number of processors, but it was definitely worth the effort (a day) to make all the intermediate results are calculated in precisely the same order (that is, order of additions) regardless of number of processors, just so I could have the strict equality test. -- David Roundy http

Re: ghc install redhat 7.3

fairness, so does gcc. I think it took two or three hours for me. It also uses lots of memory, so you may be swapping like crazy. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman

Re: Debugging

problems. -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: No safety in numbers

solution. If I remember correctly floating constants themselves are defined in terms of fromRational, so you shouldn't be introducing any additional conversion. -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL

segfault in haskell!

. This looks to me like a bug in either Text.Regex or glibc (with my bet being on Text.Regex. Any ideas how to track it down and/or work around it? Oh yeah, and I'm running ghc 6.0. Maybe this is fixed in CVS? -- David Roundy http://www.abridgegame.org

Re: how to track down out-of-bounds error?

for. Fortunately, however, I've already found my bug by a combination of inspection and good old Debug.Trace (which just served to show me which file was being read when it crashed). -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list

Re: Tokenizing Strings

s = map (concatMap (++ \n)) $ break null $ lines s (warning: untested code!) David Roundy ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Tokenizing Strings

On Wed, Apr 02, 2003 at 06:45:54AM -0500, David Roundy wrote: tok s = map (concatMap (++ \n)) $ break null $ lines s This should be tok s = map unlines $ break null $ lines s which restores the symmetry to the operation, and is therefore much more readable. David

Re: how to use POSIX function utime?

time_t (integral number of seconds since the epoch). Thanks for the pointer! It seems I had totally missed the documentation on hslibs, and was thus looking in entirely the wrong place. (Feeling somewhat foolish...) -- David Roundy http://civet.berkeley.edu/droundy

how to use POSIX function utime?

. -- David Roundy http://www.abridgegame.org ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: how to track down infinite loop?

On Wed, Mar 26, 2003 at 07:40:30AM -0800, Andy Moran wrote: On Wednesday 26 March 2003 07:23 am, David Roundy wrote: I would try using Debug.Trace.trace. It takes a string and an expression, and returns the expressions while outputting the string to stderr (I think). You can choose your

Network module problem

to use the low level interface? -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

a monadic if or case?

by something like: whatisit :: String - IO String whatisit f = do ifM doesDirectoryExist f then return dir else ifM doesFileExist f then return file else return nothing Is there any way I could do something like this? -- David Roundy http://civet.berkeley.edu

how to open a file descriptor

it with the IO monad normally. Is there any nice way to open up a file descriptor? I was looking at the ghc internal code, which has an openFd function that would do what I want, but it doesn't seem to be exported. :( Any ideas? -- David Roundy http://civet.berkeley.edu/droundy

Re: how to open a file descriptor

On Sat, Feb 01, 2003 at 07:20:56PM -0500, David Roundy wrote: Is there any nice way to open up a file descriptor? I was looking at the ghc internal code, which has an openFd function that would do what I want, but it doesn't seem to be exported. :( Any ideas? Never mind. I found out

Re: Haskell related Debian packages

of installation. -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: Last generator in do {...}

result, and work up from there, testing your code each time you add a new function. I recommend starting with the Gentle Introduction (http://www.haskell.org/tutorial/). Good luck on your haskelling! -- David Roundy http://civet.berkeley.edu/droundy

Re: New to Haskell

On Thu, Oct 24, 2002 at 09:44:17AM -0500, Andy Schmidt wrote: So let me know what I need to do in order to get started. What operating system are you using? -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL

question about lazy io

.) -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: need help optimizing a function

in that function. I'm still something like 100 times slower than GNU diff, so I think (hope, certainly!) there's still room for more improvement (another day). I'm sure I'll have more questions in a few days, once I've tracked down what the new bottlenecks are. -- David Roundy http://civet.berkeley.edu

need help optimizing a function

unless something is terribly wrong (which must be the case here). If it would help, I'd be happy to send a listing of the complete code, but it's 6.5k so I figured it'd be better not to send it, since it seems unlikely that anyone would want to run it anyways. -- David Roundy http

Re: how to debug?

that I have done nothing to optimise for speed! btw, thank you also to everyone else who gave me advice! -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman/listinfo/haskell-cafe

how to debug?

, and uses an array (which I'm none too familiar with in haskell), and there aren't any smaller parts that I can see to test. :( -- David Roundy http://civet.berkeley.edu/droundy/ ___ Haskell-Cafe mailing list [EMAIL PROTECTED] http://www.haskell.org/mailman

question about 'sort' algorithm

) sorting, and this is a bit awkward to accomplish efficiently with lists. I would have thought that this awkwardness should be dealt with in the standard library, but seeing an O(n^2) algorithm in the description troubles me. -- David Roundy http://civet.berkeley.edu/droundy

<    1   2   3   4