February 2007 - Libraries

Re: [Haskell] Haskell Xlib bindings
by Sven Panne 19 Feb '07

19 Feb '07

[ moved to libraries list ] Am Montag, 5. Februar 2007 00:15 schrieb Duncan Coutts: > [...] Perhaps these days binding xcb might be the way to go for low level > X11 stuff. I had a look and XCB, and it looks quite promising as a "better Xlib". What is not so clear to me is: * X.Org seems to use it as a basis for their Xlib implementation. Is this correct? * What about XFree86? * What about X11 implementations on *BSD, Solaris, AIX, HP-UX, etc.? * Is XCB 100% feature-complete compared to Xlib? I guess that XCB is not widespread enough yet to drop the X11 package now, but I'd like to hear what others think. OTOH, a Haskell binding for XCB can probably be generated automatically to a large degree via XSLT, if I understand things correctly, which would be a big plus. Cheers, S.

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Proposal: System.Timeout module for base
by Peter Simons 19 Feb '07

19 Feb '07

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time package needs a tiny README file
by Bryan O'Sullivan 17 Feb '07

17 Feb '07

Hello, Ashley - There's a bug open against ghc 6.6 regarding the time package, which notes that it doesn't install HsTime.h or HsTimeConfig.h when being installed. If one already has a copy of the time darcs repo, it's still not obvious how to build it. Please add a README with something like the following instructions, as a bit of Googling shows that I am not the first person to have spent a few minutes confused by this: To build the time package, you must have GNU autoconf installed. Run "autoreconf" before the usual Cabal build steps (configure/build/install). There is no need to run the "configure" script; the Cabal build process will do this for you. Thank you for your help, <b

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Where prelude alternatives/ classes and types to get values?
by Marc Weber 17 Feb '07

17 Feb '07

The prelude has some issues such like Map.empty, Sequnce.empty, Set.empty It would be much nicer to use class Empty where empty :: a except of more complicated error messages (especially for newbies) Are there already some proposals? Is this the right place to discuss these topics? I got this idea because I'm currently learning more about webfunctions. Some states (eg counters) are implemented using IORefs. I could imagine a class class ModifyIO m c where modify :: IORef a -> ( a -> a ) -> m c data Old a data New a data OldNew a = OldNew a a; modify f = do a <- readIORef io let new = f a writeIORef io new return $ f old new instance ModifyIO IO (Old a) = modify io f = modify io (\old _ -> Old old) instance ModifyIO IO (New a) = modify io f = modify io (\_ new -> New new) instance ModifyIO IO (OldNew a) = modify io f = modify io OldNew which would lead to code such as ... = do (New count) <- modify ioCounterRef (+1) ... compared to ... = do count <- readIORef ioCounterRef let count = count + 1 writeIORef ioCounterRef count ... Do you think this style is insane? Marc Weber

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Submitting a darcs patch
by Rob Hoelz 15 Feb '07

15 Feb '07

I just made some small changes (I figure smaller would be better for my first patch, and I'm also new to Haskell) to the Xlib bindings, adding support for property events and implementing an XGetAtomName function. Seeing as I'm new to darcs, how do I submit a patch and to whom do I submit it? I've already made the patch with darcs record. Thanks, Rob Hoelz

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Compiling Haskell X11 bindings
by Rob Hoelz 14 Feb '07

14 Feb '07

Hello everyone, I've been trying to improve the Haskell X11 bindings so they're more usable. So I tried to compile with my changes, and here's the output: rob@TheRing ~/programming/src/darcs/X11 $ runhaskell Setup.hs configure <A bunch of output that's ok> configure: creating ./config.status config.status: creating config.mk config.status: creating X11.buildinfo config.status: error: cannot find input file: include/HsX11Config.h.in How can I remedy this? I'm looking forward to seeing my changes in action! Thanks, Rob Hoelz

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swap minView/maxView return value.
by Jean-Philippe Bernardy 13 Feb '07

13 Feb '07

Some time ago (before ghc 6.6 / base 2.0 release), I introduced minView and maxView in Data.Set and Data.Map (at a user's request). I agreed with Robert Dockins to implement the same functionality as in his version of the Edison library. Unfortunately, I uselessly swapped the return values of minView and maxView, introducing a difference both with the corresponding functions in the edison library and similar functions in Data.Map/Set. I propose to restore the symmetry, at the cost of incompatibility. The incompatibility is probably acceptable because the functions are still short-lived. See the trac ticket for details. http://hackage.haskell.org/trac/ghc/ticket/1134 I provide no patch nor QuickCheck properties because of the triviality of the change. Cheers, JP.

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Proposal: add extra readline completion functionality
by Judah Jacobson 11 Feb '07

11 Feb '07

I propose adding some functionality to the readline package (really just wrappers of variables from that library) which is necessary to fix ghci bug #998. See the proposed patch at http://hackage.haskell.org/trac/ghc/ticket/1141 as well as the bug report at http://hackage.haskell.org/trac/ghc/ticket/998 The main addition is rl_completion_word_break_hook, which lets us change the set of word break characters based on the context of the line. Specifically for ghci, this is needed to change whether "/" is a word boundary (depending on whether we're expanding a Haskell name or a filename). Note that this variable is only present in readline version 5.0 or later; I've put in some ifdef's to support compiling against older versions. I've also included get/set functions for the rl_attempted_completion_over variable. If it's set to nonzero, readline won't use its default completer when our custom completer returns no results. Thanks, -Judah

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Proposal: Data.Proxy
by Musasabi 09 Feb '07

09 Feb '07

Hello I propose a module called Data.Proxy into the base package containing the common Proxy type used in many different libraries (e.g. HAppS, HList, ...). Attached is the source code. - Einar Karttunen

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Re: Proposal: Make StateT in mtl lazy
by Yitzchak Gale 08 Feb '07

08 Feb '07

Ian Lynagh wrote: > > Control.Monad.State.Class -- for the MonadState class > > Control.Monad.State.Lazy > > Control.Monad.State.Strict > > Control.Monad.State -- re-exports .Class and .Lazy > > Now done. Wonderful news! Thanks! -Yitz

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