April 2009 - Libraries

ANN: bindings-0.1
by Maurício 01 May '09

01 May '09

Hi, http://hackage.haskell.org/cgi-bin/hackage-scripts/package/bindings This is a package aimed at library writers, not to the everyday Haskell programmer. This the beggining of my goal to create a set of packages like: bindings-common bindings-sqlite3 bindings-openusb bindings-gsl bindings-yourFavoriteLibrary Those are not going to be Haskell style bindings. Instead, what I want is to create a set of low level bindings to the best libraries available, so that if you want to write your Haskell wrap to a foreign library using the latest Haskell features, you can do that relying on low level bindings that are comprehensive, well tested and well behaved, and with all problems regarding building and portability already solved in the best way the community was able to do. Beneficts you get by using it: - If 10 people are trying to write modules over, say, 'gsl', all of then will help contribute with bug-hunting and thoughts to the common package 'bindings-gsl'. - Use your time to write cool experiences with GADTs and Template Haskell. Leave the boring low level stuff to 'bindings-*'. - HUnit tests can be created to all bindings. If you suggest one in a ticket, and it does hold, it will be added to a test package. If you know library 'foo' very well, you won't need to read the documentation for 'bindings-foo'. A set of guidelines ensure that all these low-level bindings can be used after the original library documentation. If you know the guidelines and you know 'foo', you can use 'bindings-foo' after reading in the worst case just a few comments. These guidelines, actually, are community driven. You can find the current set here: http://hackage.haskell.org/packages/archive/bindings/0.1/doc/html/Bindings.… If you want changes or features, just open a ticket at package home: http://bitbucket.org/mauricio/bindings What I really need now is help from libraries experts. If you know your favorite library very well (specially its build process and compile time options) and are willing to answer a few questions on how it works, I'll add a binding to it. This package is a byproduct of professional, paid work. If it achieves some success, it will be maintained in the long term and, if something important depends on it, I'm willing to give maintenance to someone better than me. Best, Maurício

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Data.Map.assocs vs. Data.Map.toAscList
by Simon Hengel 30 Apr '09

30 Apr '09

In Data.Map we have three functions that do exactly the same thing (assocs, toAscList, toList), two of them (assocs, toAscList) by definition. Is this by design? What about deprecating at least one of them? Cheers, Simon Hengel

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Takusen, postgres and boolean fields
by Sasha Shipka 25 Apr '09

25 Apr '09

Let say one has to do something similar to this: execDML $ cmdbind (sql "update some_table set some_boolean_field = ? where ...") [bindP True, ...] When I do it, I have an error: DBError ("42","804") 7 "ERROR: 42804: column \"some_boolean_field\" is of type boolean but expression is of type text ..."

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Proposal: rename Data.Map.fromAscList to Data.Map.unsafeFromAscList
by Chris Eidhof 24 Apr '09

24 Apr '09

Hey all, I had some code where the function elems said a certain key was present, but looking it up returned a Nothing. After some debugging I found out that it did work if I used Prelude's lookup in combination with toList. After even more debugging it turned out there was a fromAscList somewhere deep down in my code where it should have been a fromList. Now, I know that I shouldn't have used fromAscList and that it was totally my fault. I also realize this is something that can't easily be checked using the type system, so I propose we do the next best thing: prefix the name with 'unsafe'. -chris

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Re: [Haskell-cafe] HPong-0.1.2 fails to compile in Debian ghc 6.10.1
by trentbuck＠gmail.com 23 Apr '09

23 Apr '09

"Ahn, Ki Yung" <kyagrd(a)gmail.com> writes: >>> I think this is because the filename of the OpenGL shared library is >>> /usr/lib/libGL.so.1 rather than libGL.so. >> >> No. Do not manually create the symlink. It sounds like you don't >> have the -dev packages for OpenGL installed. > > I do already have the dev package libgl1-mesa-dev installed. [...] > It's just seems to the bug of libgl1-mesa-dev 7.4-2 packaging. It > doesn't seem to make the symbolic link which it claims to make. Duh The file exists in that package, so it seems to me the problem is on your workstation, rather than in the package. I suggest you just reinstall the package in question. You may also want to use cruft(8) to find out if any other files have gone missing, and run a fsck over your root partition. $ aptitude download -t unstable libgl1-mesa-dev [...] Get:1 http://mirror.internode.on.net unstable/main libgl1-mesa-dev 7.4-2 $ dpkg -x libgl1-mesa-dev_7.4-2_all.deb . $ find -name \*.so -ls 13003 0 lrwxrwxrwx 1 twb twb 10 Apr 24 10:41 ./usr/lib/libGL.so -> libGL.so.1 $

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Re: [Haskell-cafe] HPong-0.1.2 fails to compile in Debian ghc 6.10.1
by John Goerzen 23 Apr '09

23 Apr '09

Ahn, Ki Yung wrote: > I don't know the exact reason but this should not fail since I have > Debian packaged ghc 6.10.1 and OpenGL-2.2.1.1 on my system. > > I think this is because the filename of the OpenGL shared library is > /usr/lib/libGL.so.1 rather than libGL.so. This is why we have two No. Do not manually create the symlink. It sounds like you don't have the -dev packages for OpenGL installed. You should install them and then you should be OK.

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ANNOUNCE: dataenc 0.12.1.0
by Magnus Therning 22 Apr '09

22 Apr '09

I've just uploaded version 0.12.1.0 of dataenc with the following (visible) changes compared to the previous version (0.12): - implementation of a bunch of new encodings: - xxencode - hexadecimal - quoted-printable - python escaping - url encoding - squashing of a bug in the yEncoding implementation that only manifested on 32-bit systems - an attempt to conform to the guidelines for the Haskell Platform regarding versioning and dependencies This release brings the full list of encodings to - Base16 - Base32 - Base32Hex - Base64 - Base64Url - Base85 - Hexadecimal - Python string escaping - quoted-printable - URL encoding - uuencoding - xxencoding - yEncoding The hackage page[1] now reads: Versions 0.9, 0.10.1, 0.10.2, 0.11, 0.11.1, 0.12, 0.12.1.0 Dependencies array (>=0.2.0 && <0.3), base (>=4.0.0 && <4.1), containers (>=0.2.0 && <0.3) License BSD3 Copyright Magnus Therning, 2007-2009 Author Magnus Therning Maintainer magnus(a)therning.org Category Codec Home page http://www.haskell.org/haskellwiki/Library/Data_encoding Upload date Wed Apr 22 19:40:22 UTC 2009 Uploaded by MagnusTherning /M [1]: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/dataenc -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe Haskell is an even 'redder' pill than Lisp or Scheme. -- PaulPotts

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Re: [Haskell-cafe] ANN: list-tries-0.0 - first release
by Martijn van Steenbergen 21 Apr '09

21 Apr '09

Matti Niemenmaa wrote: > In order to run properly, list-tries needs a version of 'containers' > that hasn't yet been released. I incorporated a little hack which makes > it compile even with 0.2, but some calls will fail by calling 'error': > 30 of my 1014 test cases do so. 1014 test cases?! Wow. :-) FYI, list-tries installed without any problems (with containers-0.2.0.0). Thanks, Martijn.

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NFData
by Sittampalam, Ganesh 20 Apr '09

20 Apr '09

Hi, NFData seems to be the "standard" deepseq-style class these days, but it lives in Control.Parallel.Strategies in the parallel package whereas it obviously has uses beyond this. Is there a case for moving it into its own package and module? I'd also like to add something like strictly :: (Monad m, NFData a) => m a -> m a strictly ma = do a <- ma rnf a `seq` return a The most important use for this would be to provide a standard way to do strict IO: strictly $ readFile "..." strictly $ hGetContents ... Thoughts? Cheers, Ganesh =============================================================================== Please access the attached hyperlink for an important electronic communications disclaimer: http://www.credit-suisse.com/legal/en/disclaimer_email_ib.html ===============================================================================

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ANN: time 1.1.2.4
by Ashley Yakeley 20 Apr '09

20 Apr '09

time 1.1.2.4 is available on Hackage. This version of time should compile on Windows. It's been tested on a Vista machine that didn't have cygwin, just the standard GHC install. No other changes have been made.

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