Re: [Haskell-cafe] [ANNOUNCE] hashable-generics
A note: if you use generic-deriving instead of ghc-prim, the generics code could in theory be portable as well. That package re-exports from ghc-prim when compiled with GHC, and provides a compatible fallback implementation. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Cross platform method for getting the /actual/ contents of a directory
Hello,
I'm writing a function to find out if a given directory is empty. I came up
with the obvious:
do{
contents - getDirectoryContents /home/timothy/works/current/anonGraph/
empty/ ;
let
realContents
=
filter
(\file -
case file of
. - False ;
.. - False ;
_ - True)
contents
in
return $
case realContents of
[] - True ;
_ - False}
And this works fine on linux, but I wonder. On other systems, is . and .
. allowed as file names? Couldn't a windows user actually end up with a
file name named . and this method would fail?
Thank you
Timothy
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Re: [Haskell-cafe] Where is the documentation on exception types kept?
On 12-11-07 03:36 PM, timothyho...@seznam.cz wrote: I am trying to catch an thread blocked on MVar indefinitely exception. Of course I can use ::SomeException as explained in http://hackage.haskell.org/packages/archive/base/latest/doc/html/Control-Exception.html#g:3 but there is no explanation as to how to find the more case specific exceptions. In general, because Exception instances are Typeable instances, you can get a name, and then you can use that for searches. import Control.Exception import Data.Typeable main = do aida - try (readFile no) case aida of Left (SomeException e) - print (typeOf e) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Where is the documentation on exception types kept?
Thanks! That is a neat way. At least for exceptions which I know to exists and know how to trigger ;) Tim -- Původní zpráva -- Od: Albert Y. C. Lai tre...@vex.net Datum: 7. 11. 2012 Předmět: Re: [Haskell-cafe] Where is the documentation on exception types kept? On 12-11-07 03:36 PM, timothyho...@seznam.cz wrote: I am trying to catch an thread blocked on MVar indefinitely exception. Of course I can use ::SomeException as explained in http://hackage.haskell.org/packages/archive/base/latest/doc/html/Control- Exception.html#g:3 (http://hackage.haskell.org/packages/archive/base/latest/doc/html/Control-Exception.html#g:3) but there is no explanation as to how to find the more case specific exceptions. In general, because Exception instances are Typeable instances, you can get a name, and then you can use that for searches. import Control.Exception import Data.Typeable main = do aida - try (readFile no) case aida of Left (SomeException e) - print (typeOf e) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe (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] Compiling with hsc2hs and -Wextra
Hi, when I compile my C binding using hsc2hs with the -Wextra enabled in my cabal file: cc-options: -std=c99 -Wall -Wextra -Werror This breaks the compilation started by hsc2hs: MyHsc.hsc: In function ‘main’: MyHsc.hsc:16:15: error: unused parameter ‘argc’ [-Werror=unused-parameter] MyHsc.hsc:16:27: error: unused parameter ‘argv’ [-Werror=unused-parameter] cc1: all warnings being treated as errors compiling dist/build/MyHsc_hsc_make.c failed (exit code 1) I would really like to compile my code with -Wextra -Werror though. Can't we just (void) argc; (void) argv; the arguments in the generated code, like described in [1]? Thanks Niklas [1] http://stackoverflow.com/questions/3599160/unused-parameter-warnings-in-c-code ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell Weekly News: Issue 250
Welcome to issue 250 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week of October 28 to November 3, 2012. Quotes of the Week * Cale: A list is a bit like a loop which hasn't happened yet. This operation is similar to how do I make the 5th iteration of my loop do something different from the others? * broombs: Why are there multiple packages for EitherT? broombs: edwardk: which is the better one? edwardk: broombs: either And today, we have our first quote submited via twitter! Thank you @gersei for sending this one in. If you'd like to submit quotes via twitter, add @HWNQuotes to your tweet. * @kmett:We now generate pretty core but have ugly code. Top Reddit Stories * Cartesian Closed Comic #15: Iteratees Domain: ro-che.info, Score: 75, Comments: 2 On Reddit: [1] http://goo.gl/9NpD2 Original: [2] http://goo.gl/SB7HZ * Are there any, or is there interest in starting, an online Haskell course like the Scala course on Coursera? Domain: class.coursera.org, Score: 69, Comments: 16 On Reddit: [3] http://goo.gl/UzBdF Original: [4] http://goo.gl/1Zzct * Why is this simple text processing program so much slower than in dynamic languages? Domain: honza.ca, Score: 65, Comments: 189 On Reddit: [5] http://goo.gl/jW5ow Original: [6] http://goo.gl/pPzIb * Fast Code Nation: The Bright Side of High-Level Languages Domain: bos.github.com, Score: 59, Comments: 11 On Reddit: [7] http://goo.gl/KmBRt Original: [8] http://goo.gl/jm9s7 * Fay slides Domain: fay-lang.org, Score: 56, Comments: 42 On Reddit: [9] http://goo.gl/0UM4T Original: [10] http://goo.gl/h8iZE * Data.Records: extensible records using the latest GHC features Domain: github.com, Score: 55, Comments: 44 On Reddit: [11] http://goo.gl/64wUj Original: [12] http://goo.gl/XVdB2 * Why Cabal Has Problems Domain: softwaresimply.blogspot.com, Score: 50, Comments: 41 On Reddit: [13] http://goo.gl/ZX1Ia Original: [14] http://goo.gl/TgnOG * The cabal/hackage situation, and what you can do about it Domain: alpmestan.com, Score: 49, Comments: 14 On Reddit: [15] http://goo.gl/jEGIj Original: [16] http://goo.gl/EK2DB * Brian O'Sullivan's favorite bug in GHC Domain: twitter.com, Score: 48, Comments: 12 On Reddit: [17] http://goo.gl/nMjeK Original: [18] http://goo.gl/odPH4 * Haskell for all: Hello, core! Domain: haskellforall.com, Score: 45, Comments: 6 On Reddit: [19] http://goo.gl/qXRd2 Original: [20] http://goo.gl/9cBeo * Michael Snoyman: Yesod, AngularJS and Fay Domain: yesodweb.com, Score: 43, Comments: 26 On Reddit: [21] http://goo.gl/8yfVd Original: [22] http://goo.gl/0xtPP * Cellular automata as comonads Domain: blog.sigfpe.com, Score: 41, Comments: 10 On Reddit: [23] http://goo.gl/73nr2 Original: [24] http://goo.gl/vH4TK * pipes-2.5: Faster and slimmer Domain: haskellforall.com, Score: 41, Comments: 56 On Reddit: [25] http://goo.gl/wtUZg Original: [26] http://goo.gl/rKR2D Top StackOverflow Questions * Writing cojoin or cobind for n-dimensional grid type votes: 41, answers: 3 Read on SO: [27] http://goo.gl/qbz7z * Why not be dependently typed? votes: 39, answers: 3 Read on SO: [28] http://goo.gl/1TSVh * Concrete example showing that monads are not closed under composition (with proof)? votes: 32, answers: 4 Read on SO: [29] http://goo.gl/sys7F * Monad Transformers vs Passing parameters to functions votes: 24, answers: 1 Read on SO: [30] http://goo.gl/UpU57 * Why is there no IO transformer in Haskell? votes: 16, answers: 2 Read on SO: [31] http://goo.gl/04Xc7 * Is it possible to make GHC optimize (deforest) generic functions such as catamorphisms? votes: 16, answers: 1 Read on SO: [32] http://goo.gl/f4ZlU * Is it possible to use irrefutable tilde (`~`) patterns in lambda expressions? votes: 14, answers: 1 Read on SO: [33] http://goo.gl/BmGY0 * Can Scala's Cake Pattern be implemented in Haskell? votes: 13, answers: 2 Read on SO: [34] http://goo.gl/QiMfg * Confused by the meaning of the 'Alternative' type class and its relationship to other type classes votes: 13, answers: 5 Read on SO: [35] http://goo.gl/RXNuV * How to add fields that only cache something to ADT? votes: 13, answers: 0 Read on SO: [36] http://goo.gl/FjLlX * Type algebra and Knuth's up arrow notation votes: 13, answers: 1 Read on SO: [37] http://goo.gl/kyYIn Until next time, Daniel Santa Cruz References 1. http://ro-che.info/ccc/15.html 2. http://www.reddit.com/r/haskell/comments/11t7ru/cartesian_closed_comic_15_iteratees/ 3. https://class.coursera.org/course/progfun 4.
[Haskell-cafe] Does anyone know where George Pollard is?
Hello, I sent a message to George Pollard (por...@porg.es) about his 'idna' package [1] a couple days ago, but he hasn't responded. I'd like to depend on his package for something that I'm working on, but his package fails to build (The email I sent him includes a patch that should fix up the build problems). The package hasn't been updated for 3 years and he hasn't listed a source control repository. Does anyone know where he is? If not, is there an accepted practice to resolve this situation? Should I upload my own 'idna2' package? Thanks, Myles [1] http://hackage.haskell.org/package/idna ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Does anyone know where George Pollard is?
On Wed, Nov 7, 2012 at 9:03 PM, Myles C. Maxfield myles.maxfi...@gmail.comwrote: Does anyone know where he is? If not, is there an accepted practice to resolve this situation? Should I upload my own 'idna2' package. Generally we try to contact the maintainer (and give him/her enough time to reply, in case he/she is e.g. on vacation). After that someone can announce their intention to take over maintenance of the package. -- Johan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
