January 2011 - Haskell-Cafe

Haskell Vim Indentation
by beo wulf 25 Jan '11

25 Jan '11

I am using: http://www.vim.org/scripts/script.php?script_id=1968 and http://projects.haskell.org/haskellmode-emacs/ Indenting a single do-block looks fine. However, let blocks, where blocks, nesting let/where within do's, nesting anything inside of anything -- tend to give ugly looking code. Anyone know of a good vim indenting script? Thanks!

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Chicago Haskell User Group Meetup this Thursday @ 8PM
by Jeremy Shaw 24 Jan '11

24 Jan '11

Hello, The Chicago Haskell User Group will be meeting at the Pumping Station One hackerspace this Thursday @ 8PM. This meeting coincides with a regularly scheduled Haskell class at PS:One. Among other things, we will discuss how to grow the local Chicago Haskell user community, and a possible group project. Haskell users of all levels (including no experience at all) are invited to come! Facebook Invite: http://www.facebook.com/event.php?eid=158855480832147 Pumping Station One website: http://pumpingstationone.org/ Chicago Haskell User Group Facebook Group: http://www.facebook.com/pages/Chicago-Haskell-User-Group/115989593098 Chicago Haskell User Group Mailing List: http://groups.google.com/group/haskell-chicago - jeremy

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Installing a top-level handler on an existing thread
by Leon Smith 24 Jan '11

24 Jan '11

I've been toying with a little thread manager library, and for sanity's sake I really need a way to install another top-level exception handler on an existing thread. I don't want to replace any other handlers, just put my own handler around the thread's continuation. Of course, it would be pretty easy to do if the IO monad had a nice efficient implementation of call/cc and call/cc1, although I don't need the full power of continuations. I really don't want to create my own "Thread" monad (which could use ContT), I want to be able to do it on plain old IO threads. Is there any way to do this in GHC? Best, Leon

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The F# Team are Hiring
by Simon Peyton-Jones 24 Jan '11

24 Jan '11

Dear Haskell'ers The F# team in Seattle/Redmond have an opening for a Senior Program Manager<https://careers.microsoft.com/JobDetails.aspx?ss=&pg=0&so=&rw=1&jid=33994&j…>. A demonstrated love for applied Haskell/OCaml/F# programming would be highly regarded background experience :) We also have positions open for software development engineers specializing in compilers and tools (see https://careers.microsoft.com/JobDetails.aspx?ss=&pg=0&so=&rw=3&jid=34078&j…) Kind regards & best wishes, Don Syme The F# Team are Hiring!!! * Do you have a love for modern, industry-leading programming technologies? * Can you help us take the F# language to the next level? * Do you have the vision to combine functional programming with technologies for data, cloud, web, finance and technical computing? * Do you have a passion for delivering great visual tools and a simple, clear end-to-end experience for F# programmers? * And do you want to work on a talented agile team that releases compiler sources on codeplex.com and has originated major innovations for C# and Visual Basic? If so, we have a great opportunity for you! The Visual Studio Pro team is looking for an experienced Program Manager to drive the F# area. Partnering with your engineering team in Redmond and Microsoft Research in Cambridge, you will define the F# developer experience for Visual Studio and out of band releases such as the F# PowerPack. As a strong customer advocate, you will drive changes into the F# language, libraries and tools. You will develop and update community programs that drive increased awareness and adoption of F#. Being responsible for delivering integrated solutions, you have experience in building strong cross-group partnerships, ensuring alignment of schedules and business goals, and the natural skill of getting things done. Specific responsibilities include: * Travelling to major conferences, user group meetings, and enterprises to get people excited about solving problems using F# * Defining the strategy for marketing F# to the developer community * Owning our content strategy and community engagement programs * Driving multiple concurrent projects for the F# team including Visual Studio and out of band releases * Working closely with groups within Microsoft such as Technical Computing, .NET Framework, SQL and Azure to deliver great experiences for F# developers * Contributing to the design of all aspects of F# from language & libraries to the tools that integrate with Visual Studio Basic Qualifications: * 3-5 years experience in Program Management or related experience, including a proven track record of delivering on challenging projects * A BS or equivalent degree in Computer Science, Electrical Engineering, or a related field. * Passionate for language and user experience design * Knowledge of Visual Studio, .NET & functional programming languages, and the ability to dig deep into technical challenges * Strong sense of teamwork, personal integrity, responsibility and accountability * Excellent verbal and written communication skills * Strong customer advocate, self-starter and problem solver * Strong knowledge of F# or language design on managed platforms is preferred If you'd would like more details, please either contact me (dsyme(a)microsoft.com<mailto:dsyme@microsoft.com>), or Sean Laberee (seanla(a)microsoft.com<mailto:seanla@microsoft.com>) directly. To apply immediately, please fill in the online forms<https://careers.microsoft.com/JobDetails.aspx?ss=&pg=0&so=&rw=1&jid=33994&j…> and drop us a note that you're applying. https://careers.microsoft.com/JobDetails.aspx?ss=&pg=0&so=&rw=1&jid=33994&j… don

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building hslogger error windows
by Gang Yu 24 Jan '11

24 Jan '11

Hi cafe, I just get a build error on install config-file (which depends on hslogger), C:\Documents and Settings\lenovo>cabal install hslogger Resolving dependencies... Downloading hslogger-1.1.1... Configuring hslogger-1.1.1... Preprocessing library hslogger-1.1.1... Preprocessing executables for hslogger-1.1.1... Building hslogger-1.1.1... src\System\Log\Handler\Rotating.hs:48:7: Could not find module `System.FilePath.Windows': It is a member of the hidden package `filepath-1.1.0.4'. Perhaps you need to add `filepath' to the build-depends in your .cabal fil e. Use -v to see a list of the files searched for. cabal: Error: some packages failed to install: hslogger-1.1.1 failed during the building phase. The exception was: ExitFailure 1 I am using platform-2.0, How can I solve it? Thanks in advance Gang

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Re: [Haskell-cafe] Delivery to haskell-platform@projects.haskell.org
by Yitzchak Gale 24 Jan '11

24 Jan '11

Erik de Castro Lopo wrote: > ...my mail server is rejecting the message coming back > to me... > Nun.haskell.org really should have a reverse DNS entry Ah, that is probably a casualty of the recent upgrade of the haskell.org server. As part of that process, control of the domain was moved from Yale to the community. I think someone at Galois is admin for the domain now, I'll see if I can get them to put the reverse DNS back in. I'm also creating a support ticket for community.haskell.org and taking the liberty of making you the "requestor". Regards, Yitz

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Adding a builder to the "bytestring" package?
by John Millikin 23 Jan '11

23 Jan '11

Most people who work with binary data have had to construct bytestrings at some point. The most common solution is to use a "Builder", a monoid representing how to construct a bytestring. There are currently three packages (that I know of) which include builder implementations: binary, cereal, and blaze-builder. However, all of these libraries have additional dependencies beyond just "bytestring". All three depend on "array" and "containers", and blaze-builder additionally depends on "text" (and thus "deepseq"). Since the current implementation of GHC uses static linking, every additional dependency adds to the final size of a binary. Obviously the "Builder" concept is very useful, as it has been implemented at least three times. How about adding it to the "bytestring" package itself? We could have a module Data.ByteString.Builder, with functions (at minimum): toByteString :: Builder -> Data.ByteString.ByteString toLazyByteString :: Builder -> Data.ByteString.Lazy.ByteString fromByteString :: Data.ByteString.ByteString -> Builder fromLazyByteString :: Data.ByteString.Lazy.ByteString -> Builder empty :: Builder append :: Builder -> Builder -> Builder Plus whatever implementation details might be useful to expose. Existing libraries could then add their extra features (word -> builder for binary and cereal, UTF/HTTP for blaze-builder) on top of the existing types. Is this something the community is interested in? Is there any work currently aimed at this goal?

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Is SHE (the Strathclyde Haskell Enhancement) portable?
by Maciej Piechotka 23 Jan '11

23 Jan '11

It may be strange question but: - Is SHE portable (assuming that the compiler have the extensions)? - If yes why there is only information how to use it with GHC? Regards

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ANN: follower 0.0.1
by R. Emre Başar 23 Jan '11

23 Jan '11

Hello Cafe, I'm happy to announce the first version of the anonymous Twitter following tool: follower Basically the tool allows you to follow people's tweets without having a Twitter account. It keeps a list of the people you follow and keeps track of the tweets you already saw. Thanks to the authors of those nice libraries on hackage, it's just a little more than a hundred lines (probably would be much less using the right *morphisms) hacked up in an hour or so. Any comments, bug reports, rants, requests and patches are welcome. Get it from hackage: http://hackage.haskell.org/package/follower -- R. Emre Başar İstanbul Bilgi University Department of Computer Science

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Tool for evaluating "GHCi>" lines in a source file
by Steffen Schuldenzucker 23 Jan '11

23 Jan '11

Hi, some time ago I read of a small tool that extracts lines like "GHCi> some_expression" from a source file and appends GHCi's output to them. Now I can't find it again. Does anyone remember its name? Thanks. Steffen

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