February 2007 - Libraries

Is there already a list class?
by Marc Weber 13 May '07

13 May '07

Hello. Is here the right place to request a list class? eg class List l e where (:) :: e -> l e -> l e head :: .. This might be used in Data.Set, Data.Map class StorableAsList l e t where fromList :: l e -> t toList :: t -> l e I'd like to help implementing/ writing it. Do you consider this beeing a useful enhancement? Cheers Marc Weber

12 20

proposal: add 'unsafeCoerce'
by Malcolm Wallace 02 Apr '07

02 Apr '07

Currently, all implementations provide either the 'unsafeCoerce' or 'unsafeCoerce#' functions, but they live in implementation-specific locations. This proposal is to adopt the Haskell'98-compatible name 'unsafeCoerce', and to add it to the standard base library package. Suggested location: Data.Function.Unsafe? http://hackage.haskell.org/trac/ghc/ticket/994 Regards, Malcolm

17 45

Control.Monad.Cont documentation
by Andriy Palamarchuk 28 Mar '07

28 Mar '07

Documentation for the Continuation monad. Right now this module does not have any haddock comments. Per Jeff Newbern's gracious permission included relevant information from his cool tutorial "All About Monads" http://www.nomaware.com/monads/, created a couple of examples. The source of the module and haddock output for it are attached to the ticket: http://hackage.haskell.org/trac/ghc/ticket/1169 Here is the generated haddock output: http://hackage.haskell.org/trac/ghc/attachment/ticket/1169/Control-Monad-Co… Deadline for the proposal - 2 weeks. Questions, comments, suggestions? Andriy Palamarchuk ____________________________________________________________________________________ Yahoo! Music Unlimited Access over 1 million songs. http://music.yahoo.com/unlimited

3 2

Data.IntMap.findMax is missing
by Christian Maeder 18 Mar '07

18 Mar '07

recently I've switched from "Data.Map.Map Int" to "Data.IntMap.IntMap", but I was disappointed because I did not find a function that would yield the maximum key faster than in linear time, i.e. O(log n). In fact the whole "Min/Max" section is missing in Data.IntMap (resp. Data.IntSet) compared to Data.Map (resp. Data.Set). (The section "Indexed" is also only in Data.Map.) Would somebody care to fix this? Cheers Christian

2 2

Re: [Haskell] Composing applicative functors?
by Ross Paterson 12 Mar '07

12 Mar '07

[redirecting to libraries] On Wed, Feb 21, 2007 at 04:23:50PM -0800, Conal Elliott wrote: > Is the composition instance of Control.Applicative defined somewhere? I see > it in the McBride & Paterson paper [1], but not in the library docs [2]. > I'd rather pull it in from a library than (re)define it myself. > > [1] http://www.soi.city.ac.uk/~ross/papers/Applicative.pdf > [2] > http://www.haskell.org/ghc/docs/latest/html/libraries/base/Control-Applicat… It's not defined in the libraries. The type (and the identity functor) should probably go in the module that defines Functor (currently Control.Monad) with a Functor instance, and an Applicative instance in Control.Applicative.

3 4

EnumSet and EnumMap
by Chris Kuklewicz 08 Mar '07

08 Mar '07

I could not quickly find anyone else writing this boiler plate, so I have posted this useful wrapper on the Haskell wiki at http://haskell.org/haskellwiki/EnumSet_EnumMap This uses a cheap newtype to wrap IntSet and IntMap so that you can store any Enum in them. It saves either writing many toEnum/fromEnum functions or using the slower and more generic Data.Set and Data.Map. The original motivation was to go from Map Char to IntMap. And as a bonus, the type signature of the newtype is the same kind as Data.Set and Data.Map (which matters when declaring instances...) > newtype EnumSet e = EnumSet {unEnumSet :: S.IntSet} > deriving (Monoid,Eq,Read,Show,Ord) > newtype EnumMap k a = EnumMap {unEnumMap :: M.IntMap a} > deriving (Eq,Read,Show,Ord,Monoid,Foldable,Functor) This has been quickly tested with GHC 6.6 and may contain typographical errors I have not caught yet. -- Chris

3 6

[hoelz@wisc.edu: [Haskell] Haskell Xlib bindings]
by dons＠cse.unsw.edu.au 06 Mar '07

06 Mar '07

This question is best asked on the libraries(a)haskell.org list, so I'll forward it there. Failing that, best to contact the maintainer of the xlib package. Cheers, Don ----- Forwarded message from Rob Hoelz <hoelz(a)wisc.edu> ----- Date: Sun, 04 Feb 2007 16:00:44 -0600 From: Rob Hoelz <hoelz(a)wisc.edu> To: haskell(a)haskell.org Subject: [Haskell] Haskell Xlib bindings Hello everyone, This question probably belongs in GUI, but I tried posting there a week ago and have yet to get a response. My question is this: Why do the Haskell Xlib bindings have no way to extract the property event from an event pointer? For example, the following functions are available: get_KeyEvent, get_ButtonEvent, get_MotionEvent, etc. but there's no get_PropertyEvent. Why was this left out? It seems pretty critical to the functionality of an Xlib program to someone who's been programming in C with Xlib for quite some time. Thanks, Robert Hoelz _______________________________________________ Haskell mailing list Haskell(a)haskell.org http://www.haskell.org/mailman/listinfo/haskell ----- End forwarded message -----

4 6

Proposal: System.Timeout module for base (Trac #980)
by Peter Simons 01 Mar '07

01 Mar '07

4 10

ANNOUNCE: Gtk2Hs version 0.9.11 released
by Duncan Coutts 28 Feb '07

28 Feb '07

Gtk2Hs - A GUI Library for Haskell based on Gtk+ Version 0.9.11 is now available from: http://haskell.org/gtk2hs/download/ The source tarball and an installer for Windows are available. Packages are available for Gentoo and FreeBSD. Packages for various other platforms should become available soon (hopefully including Fedora, Debian and Darwin). Changes since 0.9.10: * works with GHC 6.6 and Gtk+ 2.10.x * new typed tree/list widget API * new OpenGL widget added * new cairo SVG package (for rendering SVG images on cairo surfaces) * new implementation of the Graphics.SOE API * new glade tutorial * many more demo programs (clock, graph, traffic congestion sim, fonts, noughts & crosses, opengl, svg and updated profile viewer and other tree/list demos) * much smaller binaries (thanks to the ghc 'split objs' feature) * many bugs fixed * new functions for working with the threaded RTS * various minor documentation improvements Gtk2Hs feature highlights: * automatic memory management * Unicode support * nearly full coverage of Gtk+ 2.8 API * support for several additional Gtk+/Gnome modules: * Glade visual GUI builder * cairo vector graphics library * SVG rendering for cairo * OpenGL extension (works with HOpenGL) * GConf, Gnome's system for storing app preferences * SourceView, code editor widget with syntax highlighting * the Mozilla browser rendering engine in a widget * an implementation of the Graphics.SOE API * extensive haddock API reference documentation * multi-platform support with native look * LGPL licence Platforms and requirements: * builds from source on Linux, Windows, MacOS X, FreeBSD and Solaris * builds with GHC 6.2 - 6.6 * works with Gtk+ version 2.0 through to 2.10 * SVG support requires librsvg version 2.16 or later Please report all problems to gtk2hs-devel(a)sourceforge.net Contributions and feedback are also most welcome. Windows release notes: The installer expects GHC 6.6 or 6.4.2. Support for GHCi is only available with GHC-6.6. Profiling libs are included (though you do not need to install them if you want to save disk space) The installer now comes bundled with Gtk+ itself so there's no need to download it separately. Hopefully this should also make the installation process a bit more reliable if only by reducing the number of configuration combinations. The windows build does not include the svgcairo, sourceview, gconf or mozembed packages since they introduce rather a large number of dependencies and would make the installer a much bigger download. Duncan (on behalf of the Gtk2Hs team)

1 0

Re: hasktags - small patch
by Claus Reinke 23 Feb '07

23 Feb '07

[cc-ed to libraries, as they seem to be more appropriate for cabal topics] > Some time ago I've tweaked cabal to start ghci with package options > given in the .cabal file. > > Perhaps it might be useful for someone: yes, i'd like to see something like this in cabal. cf also http://www.mail-archive.com/glasgow-haskell-users@haskell.org/msg11101.html claus > module Main where > import Distribution.Simple > import Distribution.Simple.Configure > import Distribution.Simple.LocalBuildInfo > import System > import System.Process > import System.Exit > import Monad > > main= do > args <- getArgs -- check args to launch ghci > when (length args > 0) $ do > when ((args!!0) == "ghci") $ do > lbi <- getPersistBuildConfig > let packageArgs = (concat.concat) [ [" -package ", showPackageId pkg] | pkg <- packageDeps lbi ] > system("ghci " ++ packageArgs) > exitWith ExitSuccess > defaultMain -- fallback to defaultMain > > Then you can use ./setup ghci to start ghci > It is incomplete but should work for default packages.. > > Marc > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users(a)haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

1 0