February 2015 - Haskell-Cafe

Re: [Haskell-cafe] learn you a good haskell exercises
by Roelof Wobben 04 Feb '15

04 Feb '15

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learn you a good haskell exercises
by Roelof Wobben 04 Feb '15

04 Feb '15

Hello, If I want to look if I understand the contents of the book , are these good exercises : https://github.com/noelmarkham/learn-you-a-haskell-exercises Roelof

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Haskell opportunities at Facebook
by Bryan O'Sullivan 04 Feb '15

04 Feb '15

Hi, friends – I have a number of very interesting openings at Facebook HQ in Menlo Park, California. There are two different teams hiring. The first set of positions are for an entirely new team. This project involves distributed systems, data mining, and machine learning. There may be roles on this team for less experienced candidates in a few months, but right now we are looking for people who have written a reasonable amount of Haskell, have built real production systems in some language or other (and have the scars to prove it), and can contribute in major ways to the design and construction of a demanding new system that we're building from scratch. The second set of positions are for a cousin team, which is building on the success of our Haxl project to extend our capability to fight spam and malware. For these roles, we're open to a broader range of experience levels. If you're interested, please drop me an email with a current CV. Cheers, Bryan.

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hiring fp engineers for information security systems
by Khushil Dep 04 Feb '15

04 Feb '15

About Guardtime We are team of US and Estonian scientists, network architects, software developers and security specialists who have decades of experience building cyber security solutions in our nations' military, supporting national objectives for mission and information assurance. In 2007 we invented Keyless Signature Infrastructure (KSI), a block-chain security technology designed for real-time detection and mitigation of cyber attack. About The Role We're looking for experienced functional software engineers to work on real-time backend systems dealing with high volume events. We need people who want to build systems to apply the power of workflow processing to security events to build deep intelligence platforms. We want people who understand the benefits of converged understanding over imperative understanding. About You - You should have an appetite for tackling complex and interesting software challenges. - Want to build systems that handle data on a global scale in a timely manner. - Have a strong understanding of Linux/UNIX kernel operations - Understand the value of documentation. - Be able to disseminate complex ideas to a wider audience. - Prepared to work in an agile but structured manner. - Prepared to travel in the E.U. - Prepared to travel to the U.S.A. on a quarterly basis. Minimum Qualifications - BS in Computer Science, Mathematics or Physics or equivalent work and life experience. - Clojure, Scala, Java, C/C++ Programming experience. - Large systems software design and development experience, with knowledge of Unix/Linux. Preferred Qualifications - MS or PhD in Computer Science, Mathematics or Physics. - Strong FP skills. - Strong competencies in data structures, algorithms, and software design. - Haskell, Clojure, Scala, Java, C/C++, NodeJS, Python programming experience, database design, knowledge of TCP/IP and network programming. Application Process In the first instance please send your C.V. and GitHub username (if you have one) to khushil.dep(a)guardtime.com. We have a two stage interview process and we hire quickly.

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GHC API - list all exports of a module
by Jochen Keil 02 Feb '15

02 Feb '15

Dear Cafe, currently I'm working on a small program for which I need a list of all *exported* function and data types. In order to achieve this I've been toying around with the GHC API. My observations so far: * Using the pure `parser` function yields a `HsModule` object, which gives me a list of all exports and all declarations (internal & exported). I cannot or don't know how to use the list of exports (just `RdrName`s) to filter the declarations. * Using `parseModule` (which is essentially the same as the `parser` function) and `typecheckModule` on a `ModuleGraph` yields a `TypecheckedModule` object which contains a list of exported `Name`s which in turn can be used to get additional information about them. So, the second approach seems more promising, but I'm not too happy with it. The reason is that calling `typecheckModule` results in a compilation of the module and all of its dependencies, which I think is not necessary for what I want to achieve. This is especially cumbersome for large modules like `GHC.hs` where I'm struggling to figure out all of the dependencies without the build system. My main goal would be to have a program which takes two modules of different versions, compare them and highlight the differences between them. I think that'd be helpful for upgrading dependant packages or for writing compatibility layers. Thank you and all the best, Jochen

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Cabal config file - default install flags?
by Lucas Paul 02 Feb '15

02 Feb '15

I'd like to have cabal automatically use -j8 when I cabal install something. Is there something I can put into the .cabal/config file that will accomplish this? More generally, where can I find documentation on that config file? - Lucas Paul

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Template Haskell attempts to load mingw32.dll during build
by Darren Grant 02 Feb '15

02 Feb '15

Hi all, Windows GHC 7.8.4 build issue here: I've noticed that GHC will attempt to link mingw32 if a related dependency (in my case sdl2) is required in a TH pass. Unsurprisingly, the OS fails to find the imaginary mingw32.dll file. Are there any known resolutions to this quirk? Cheers, Darren

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What could be the possible reason of linking errors on "_info" and "_closure"?
by Magicloud Magiclouds 02 Feb '15

02 Feb '15

Hi, I am making a cabal project including a library and a executable using the library. Building the library is fine. But when linking src/main, I got "undefined reference to someFunction1_info" and "someFunction1_closure". -- 竹密岂妨流水过山高哪阻野云飞 And for G+, please use magiclouds#gmail.com.

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ANNOUNCE: monad-levels
by Ivan Lazar Miljenovic 02 Feb '15

02 Feb '15

I'm pleased to announce the first release of my new monad-levels library (aka Yet Another Monad Transformer Library ;-) http://hackage.haskell.org/package/monad-levels I've written more about the motivations of the library here: https://ivanmiljenovic.wordpress.com/2015/02/02/monadic-yak-shaving/ -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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parallelism and purity
by Kazu Yamamoto 01 Feb '15

01 Feb '15

Hi cafe, I received questions about parallelism in Haskell. I'm familiar with concurrency but not with parallelism. So, let me ask: Q1) Are there any *applications* using Haskell parallelism? Q2) What kind of parallelism is used in the application? - Task parallel - Data parallel - Data-flow paralle? - etc Q3) Does Haskell purity contribute for the application in the parallelism point of view? I'm one of the translators of "Parallel and Concurrent Programming in Haskell" into Japanese. So, please don't say read the book. :-) --Kazu

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