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ANN: stm-chans 3.0.0.3
by wren romano 30 Mar '15

30 Mar '15

-------------------------------------------- -- stm-chans 3.0.0.3 -------------------------------------------- The stm-chans package offers a collection of channel types, similar to Control.Concurrent.STM.{TChan,TQueue} but with additional features. -------------------------------------------- -- Changes since 3.0.0 (2013-05-29) -------------------------------------------- Cleaned up the header gunk to compile cleanly under GHC 7.10. No actual code has been altered. -------------------------------------------- -- Long description -------------------------------------------- In particular stm-chans offers the following data types: * Control.Concurrent.STM.TBChan: Bounded FIFO channels. When the channel is full, writers will block/retry. This ensures that the writers do not get too far ahead of the readers, which helps to make sure that memory and cpu resources are used responsibly. * Control.Concurrent.STM.TMChan: Closeable FIFO channels. * Control.Concurrent.STM.TMQueue: Closeable FIFO queues. Like TChan (Maybe a) but with a monotonicity guarantee that once Nothing is returned all future reads will be Nothing as well. * Control.Concurrent.STM.TBMChan: Bounded Closeable FIFO channels. * Control.Concurrent.STM.TBMQueue: Bounded Closeable FIFO queues. Combines the capabilities of TBChan and TMChan. -------------------------------------------- -- Links -------------------------------------------- Homepage: http://code.haskell.org/~wren/ Hackage: http://hackage.haskell.org/package/stm-chans Darcs: http://community.haskell.org/~wren/stm-chans Haddock (Darcs version): http://community.haskell.org/~wren/stm-chans/dist/doc/html/stm-chans -- Live well, ~wren

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ANN: logfloat 0.13.3
by wren romano 30 Mar '15

30 Mar '15

-------------------------------------------- -- logfloat 0.13.3 -------------------------------------------- This package provides a type for storing numbers in the log-domain, primarily useful for preventing underflow when multiplying many probabilities as in HMMs and other probabilistic models. The package also provides modules for dealing with floating numbers correctly. This version drops support for Hugs and GHC < 7.8. Nothing major has changed, so they should still work; it's just that they're no longer officially supported. Thus, this version of the library provides a transitional point between backwards compatability and adding new features (see below). -------------------------------------------- -- Changes since 0.12.1 (2010-03-19) -------------------------------------------- * Monomorphized logFloat, logToLogFloat, fromLogFloat, and logFromLogFloat: that is, they all take/return Double now. The change was made to help reduce the need for explicit type signatures. It shouldn't really affect most users, since it seems noone was really making use of the polymorphism provided by previous versions. To get the previous behavior back, just explicitly add calls to realToFrac wherever necessary. * Fixed some instances to get them to compile under the new role-based type system of GHC 7.10 * Cleaned up various extraneous rewrite rules, specializations, etc * Added the functions sum, product, and pow. Both sum and product preserve more precision than the fold-based definitions in the Prelude. Moreover, sum is _much_ faster than the Prelude version, since it only requires crossing the log/exp boundary n+1 times, instead of 2*(n-1) times. The only downside is that sum requires two passes over the input and thus is not amenable to list fusion. -------------------------------------------- -- Upcoming changes (0.14+) -------------------------------------------- * Since the Data.Number.RealToFrac module is no longer required by any of the others, it will probably be forked off to a separate package in order to improve portability of the rest of the package by removing the need for MPTCs. * There's long been clamoring for adding a vector:Data.Vector.Unboxed.Unbox instance. I've been reluctant to add such an instance due to wanting to retain backwards compatibility and portability. Having dropped support for Hugs and older versions of GHC, I'm now willing to add them in. The logfloat library is conceptually quite simple, and thus to whatever extent possible I'd still like to retain portability to non-GHC compilers. So if you are interested in using logfloat with another compiler/interpreter but run into problems (e.g., due to the type families required by the vector library), please get in touch and I'll try to get things to work. -------------------------------------------- -- Compatibility / Portability -------------------------------------------- The package is compatible with GHC 7.8.3 and 7.10.1. It may still compile with older versions of GHC (or even Hugs!), however they are no longer officially supported. The package is not compatible with nhc98 and Yhc because Data.Number.RealToFrac uses MPTCs. However, that module is no longer required by any others, and all the other modules should be compatible with these compilers. Thus, it should be fairly easy to port. If you do so, please let me know and I'll try to incorporate support for them. -------------------------------------------- -- Links -------------------------------------------- Homepage: http://code.haskell.org/~wren/ Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/logfloat Darcs: http://code.haskell.org/~wren/logfloat/ Haddock (Darcs version): http://code.haskell.org/~wren/logfloat/dist/doc/html/logfloat/ -- Live well, ~wren

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[announce] pipes-cliff - library for streaming to and from processes with Pipes
by Omari Norman 30 Mar '15

30 Mar '15

Sometimes you have to write Haskell code to interact with external processes. What a bother. The System.Process module makes it easy to send data in and out, but what if you want to stream your data in constant time and space? Then you need to cobble together your own solution using the provided Handles. Or you can use pipes-cliff, which lets you use the excellent Pipes library to stream your data in and out. Some simple examples in the package get you started. https://hackage.haskell.org/package/pipes-cliff Also, take a look at the README.md file, which lists some similar packages. Maybe one of those will work better for you. https://github.com/massysett/pipes-cliff/blob/master/README.md

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OS X builds of GHC 7.8.4, 7.10.1-rc2, and 7.10.1-rc3
by Miëtek Bak 30 Mar '15

30 Mar '15

An OS X build of GHC 7.10.1-rc3 is now available, courtesy of Mark Lentczner. This is in addition to the GHC 7.8.4 and 7.10.1-rc2 builds Mark has made available on February 2. Thanks, Mark. GHC 7.8.4 for OS X can already be downloaded from haskell.org, even though it’s not mentioned on the GHC 7.8.4 webpage: https://downloads.haskell.org/~ghc/7.8.4/ghc-7.8.4-x86_64-apple-darwin.tar.… To avoid running up Mark’s bandwidth bill, I’m omitting the URL to his staging area. I’ve mirrored all three builds in Halcyon public storage: 7.8.4: https://halcyon.global.ssl.fastly.net/original/ghc-7.8.4-x86_64-apple-darwi… 7.10.1-rc2: https://halcyon.global.ssl.fastly.net/original/ghc-7.10.0.20150123-x86_64-a… 7.10.1-rc3: https://halcyon.global.ssl.fastly.net/original/ghc-7.10.0.20150316-x86_64-a… Binary builds of GHC, repackaged with documentation removed, are also available in Halcyon — on OS X 10.10, 10.9, 10.8, and a considerable number of Linux distributions. This includes GHC 7.10.1-rc3, 7.10.1-rc2, 7.8.4, 7.8.3, 7.8.2, 7.6.3, 7.6.1, 7.4.2, 7.2.2, and 7.0.4. Using Halcyon, installing GHC together with cabal-install is expected to take 20-30 seconds: https://halcyon.sh/tutorial/#install-ghc-and-cabal -- Miëtek https://mietek.io

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Information about "definitive-base" prelude replacement
by Clinton Mead 30 Mar '15

30 Mar '15

I've played around a bit with "classy-prelude", but recently I stumbled into "definitive-base", on hackage here - https://hackage.haskell.org/package/definitive-base. The documentation is sparse, but there's some brief information here: https://marc.coiffier.net/projects/definitive-framework.html It looks interesting, but I was wondering if anyone has used it as a replacement prelude, and perhaps written/blogged on it? I'm just looking for a bit of a primer I guess.

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LTS Haskell 2.0: Last call
by Michael Snoyman 29 Mar '15

29 Mar '15

This is the last announcement about the upcoming LTS 2 release, which is schedule for this Wednesday, April 1 (no joke). For those unfamiliar with the process: we will essentially be taking that day's Stackage Nightly and promoting it to LTS 2, and locking down the major versions of all packages in that package set until LTS 3. If you'd like to get any additional packages in, please send your pull requests now[1]. I'd also like to call attention to the current upper bounds issues[2]. If we can get any of these issues resolved before Wednesday, then newer versions of the relevant packages can make it into LTS 2. Otherwise, LTS 2 will continue with the old versions. (Alternatively, we can consider dropping the packages with restrictive upper bounds, if there's demand to do so.) Things worth pointing out: * primitive 0.6 is out, and introduces very minimal breaking changes. If you can get your packages to support the new version (likely with just a cabal file change), that would be great. * criterion 1.1 is out. I may simply disable benchmarks on the relevant users to allow the new version to slip in. * QuickCheck 2.8 would be a nice addition * lens 4.8 is blocked on a number of diagrams-* packages and a few others. I have no idea how complicated the changes are there. * blaze-builder 0.4 is blocked by snap, and unlikely to unblock in time, which likely means we'll have two ByteString Builder variants for this release * wizards depends on an old control-monad-free Thanks for everybody's participation! [1] https://github.com/fpco/stackage#get-your-package-included [2] https://github.com/fpco/stackage/issues?q=is%3Aopen+is%3Aissue+label%3Aboun…

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cabal install wx failures
by Jeffrey Brown 29 Mar '15

29 Mar '15

Hi, I switched OSs to change other problems and in the process lost wxHaskell. The first time I tried to add it to my new system, cabal install wx gave me more output, installing a lot of things. Since then it has only given this: jeff@linux-ee07:~> cabal install wx Resolving dependencies... [1 of 1] Compiling Main ( /tmp/wxc-0.91.0.0-16672/wxc-0.91.0.0/Setup.hs, /tmp/wxc-0.91.0.0-16672/wxc-0.91.0.0/dist/setup/Main.o ) Linking /tmp/wxc-0.91.0.0-16672/wxc-0.91.0.0/dist/setup/setup ... Configuring wxc-0.91.0.0... Warning: No config found to match: /usr/bin/wx-config --version=2.9 --version-full in /usr/lib64/wx/config If you require this configuration, please install the desired library build. If this is part of an automated configuration test and no other errors occur, you may safely ignore it. You may use wx-config --list to see all configs available in the default prefix. readProcess failed: readProcess: wx-config "--version=2.9" "--version-full" (exit 1): failed Configuring wxc to build against wxWidgets 3.0.2.0 Building wxc /usr/bin/gcc -Wl,--hash-size=31 -Wl,--reduce-memory-overheads -Wl,--disable-new-dtags -Isrc/include -I/usr/include/wx-3.0 -I/usr/lib64/wx/include/gtk3-unicode-3.0 -D__WXGTK__ -DWXUSINGDLL -DwxDEBUG_LEVEL=0 -D_FILE_OFFSET_BITS=64 -DwxcREFUSE_MEDIACTRL -fPIC -c src/cpp/apppath.cpp -o dist/build/src/cpp/apppath.o gcc: error trying to exec 'cc1plus': execvp: No such file or directory Failed to install wxc-0.91.0.0 cabal: Error: some packages failed to install: wx-0.91.0.0 depends on wxc-0.91.0.0 which failed to install. wxc-0.91.0.0 failed during the building phase. The exception was: ExitFailure 1 wxcore-0.91.0.0 depends on wxc-0.91.0.0 which failed to install. jeff@linux-ee07:~> The file /usr/bin/wx-config exists. It may have gotten there today when I installed some wx packages via zypper (because I use openSuse). I don't remember which, but in the wx-configg file appear these lines: this_version="3.0" [ -z "$output_option_release" ] || echo "3.0" [ -z "$output_option_version" ] || echo "3.0.2" [ -z "$output_option_version_full" ] || echo "3.0.2.0" so I believe the version of wx I have is 3.0.2.0. I'm running OpenSuse 13.2 on a Lenovo Thinkpad Edge 535 or 545. Thanks, Jeff

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Command Line Args passed to wxHaskell
by Michael Jones 29 Mar '15

29 Mar '15

I am seeing strange behavior with a wxHaskell app compiled on Windows 7. On Linux, all is well. I can call my app like: app +RTS -N4 -RTS myArg And in the app I can process the myArg and start a wxHaskell frame. When I compile the same application on Windows 7, I get an error dialog box that says: “Unexpected parameter `+RTS`. And a second Usage dialog that looks like it comes from wxHaskell. I am not sure why Windows is different, but perhaps it is the fact that on Windows 7 I compiled up wxHaskell 0.92, and on Linux I used 0.91 from a cabal update. I used 0.92 on on Windows because I could not get 0.91 to compile due to some type problems where the wxPack version was incompatible with a header file and the Haskell compiler related to 64 bit types long long. There is some noise about this on the web, but no solutions. Nonetheless, I assume that args are grabbed directly by wxHaskell and Environment.getArgs does not consume them such that they are still available to wxHaskell. Is there some way to consume arguments so they are no longer available or a way to modify them so that when wxHaskell starts up it sees arguments I can control in code? In wx there is an API to set arguments, but it does not seem to be part of wxHaskell. So I think I need something I can do outside the wxHaskell API. Mike

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DSL
by Закиров Марат 28 Mar '15

28 Mar '15

Hi folks! Are there any examples of Domain Specific Language (DSL) on Haskell? Thank you in advance. -- *Regards, Marat.* *С уважением Марат.*

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I need your feedback (GSoC): Analyzing stock market in Haskell
by CESAR FABIAN ORCCON CHIPANA 27 Mar '15

27 Mar '15

Hello This is my second proposal. It would be really useful for me to read your comments about this proposal. http://cfoch-dev.tumblr.com/post/114754745097/analyzing-stock-market-in-has… Thanks, Fabián Orccón -- ------------------------------------ Fabián Orccón (cfoch) http://cfoch.tumblr.com http://cfoch-art.tumblr.com http://cfoch-dev.tumblr.com

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