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submitted by chrisdoner
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submitted by DrBartosz
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I'm an Italian IT teacher and I would like to introduce functional programming using haskell. As classroom activity, I would like to build-up a simple fuzzy inference engine. Does anyone know if someone has experience in teaching haskell to high school students or something has already been done with fuzzy logic and haskell? I found only this page: http://www.haskell.org/haskellwiki/AI/Logic/Fuzzy with some information and a link to a pubblication (with fee, I didn't download yet). Thanks Claudio _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Hello, I have found the Conduit abstraction to be very well suited to a set of problems I am facing. I am however wondering how to implement "branching" conduits, and even conduit pools. I am currently in the process of rewriting parts (the simple parts) of the Logstash tool. There is a sample program that I use here: https://github.com/bartavelle/hslogstash/blob/deprecateUtils/examples/RedisToElasticsearch.hs As it can be seen, it uses a "Redis" source, a conduit that decodes the JSON ByteString into a LogstashMessage, a conduit that stores it into Elasticsearch and outputs the result of that action as an Either, and finally a sink that prints the errors. My problem is that I would like more complex behaviour. For example, I would like to route messages to another server instead of putting them into Elasticsearch when the LogstashMessage has some tag set. But this is just an example, and it is probable I will want much more complex behavior soon. I am not sure how to proceed from here, but have t

Hi Ertugrul, Thank you for the detailed reply. From what you wrote, partial FFI still seems like the way to go. Unfortunately Ogre isn't the only large library I'm using, so "difficult" several times over sounds like a good way to handicap the project early on. I'm perfectly happy to use Haskell for the strengths that will most benefit my project. I can always go back and try to bring the C++ specific parts into the fold once a prototype is up and running. As it seems there is a great deal of c/c++ to do either way, I would really appreciate so thoughts towards my original question. What practices in C++ are preferred by Haskell users, in the know, for the parts of the app that will not be pure Haskell? Should I be looking to avoid OOP? Dependency Injection? I wont reiterate all the facets of the first post, but it would help me immensely to zero in on a few patterns and strategies that can minimized the damage I inflict in c++ land. Thanks, Casey p.s. With "That used to be true, but the reason

Hi Cafe, I downloaded the latest hugs98 source package, unzip and build, I get the following link errors. It seems many symbols are not defined, am I missing same depending libraries? This is my machine info: ➜ hugs98-plus-Sep2006 git:(master) ✗ uname -a Darwin lan-seimatoMacBook-Air.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:25:48 PDT 2012; root:xnu-1699.32.7~1/RELEASE_X86_64 x86_64 ================================ Preprocessing Network/Hackage/Version Undefined symbols for architecture x86_64: "_environ", referenced from: ___hscore_environ in ccuTP291.o (maybe you meant: ___hscore_environ) ld: symbol(s) not found for architecture x86_64 collect2: ld returned 1 exit status runhugs: Error occurred ERROR "libraries/bootlib/Foreign/C/Error.hs" - Error while running compilation command 'gcc -DNDEBUG=1 -g -no-cpp-precomp -flat_namespace -shared -fPIC -D__HUGS__ "-Ihugsdir/include" -o "libraries/bootlib/Foreign/C/Error.so" "libraries/bootlib/Foreign/C/Error.c" -Ipackages/b

Hi, I'm working on a project in Haskell and C++ where the former is the brains and the latter is for UI, interaction etc. I've read this http://www.altdevblogaday.com/2012/04/26/functional-programming-in-c/ and a number of other haskell posts suggesting the OOP is not the way to go. Without trying to emulate functional programming through templates or boost::phoenix, what approaches do you all favor when designing parts of an application in C++? Patterns to embrace or avoid? Should I just use functions and handle things with name spaces? I was thinking about handling the callbacks with boosts signals and slots 2 I know this is not entirely haskell centric, but it is a question for haskell users. Thanks, Casey

Welcome to issue 256 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the weeks of January 20 to 26, 2013. Quotes of the Week * elliott: cmccann: unfortunately it is too perfect an abstraction to be useful. * SamanthaD: shachaf: you're one of those dirty imperative communists who want the state to dictate everything! * monochrom: I refuse camel case and mark zuckerberg. same level. not negotiable. * mauke: a newtype is like an existing type but wearing glasses and a fake mustache and a sign saying "you've never seen me before" Top Reddit Stories * Taking magic out of GHC or: Tracing compilation by transformation (intro to Core transformations, inlining,.. Domain: ics.p.lodz.pl, Score: 59, Comments: 2 On Reddit: [1] http://goo.gl/lJmsb Original: [2] http://goo.gl/IbJ5O * Introduction to Haskell IO Domain: haskellforall.com, Score: 57, Comments: 26 On Reddi

If you possess multiple instances (may be different versions, may be same version different builds) of a package, life can be hard and confusing. The problems are explained in my http://www.vex.net/~trebla/haskell/sicp.xhtml and faced by many people regularly. (Just read this mailing list.) cabal-install has a mechanism for not adding more instances. It is available since version 0.14.0, or earlier. It is just little known. It is also a bit manual. You have to give 1 instruction for each package. If you want to say it for n packages, you have to give n instructions. Also, if you give such an instruction for a package you do not already have, there is a problem: now you can't install that package. To insure package sanity, add these lines to your $HOME/.cabal/config, one line per package you want to protect. (Cannot merge into one line.) constraint: array installed constraint: bytestring installed constraint: Cabal installed constraint: containers installed ... Generally, do it for every package

Hello, (sorry for the repost, I forgot to add a subject.) I was just doing some work with Template Haskell and I noticed that the AST does not have support for record puns and wild-cards. I know that these could be desugared into ordinary record patterns but I think that it would be more convenient for users (and also more consistent with the rest of the AST) if we provided direct support for them. So I propose to change: type FieldPat = (Name, Pat) to data FieldPat = RecordFileldP Name Pat -- x = P | RecordPunP Name -- x | RecordWildP -- .. Would there be any objections to doing so? If not, I'd be happy to have a go at making the change. -Iavor _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users< at >haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

Hello, I was just doing some work with Template Haskell and I noticed that the AST does not have support for record puns and wild-cards. I know that these could be desugared into ordinary record patterns but I think that it would be more convenient for users (and also more consistent with the rest of the AST) if we provided direct support for them. So I propose to change: type FieldPat = (Name, Pat) to data FieldPat = RecordFileldP Name Pat -- x = P | RecordPunP Name -- x | RecordWildP -- .. Would there be any objections to doing so? If not, I'd be happy to have a go at making the change. -Iavor _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users< at >haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

Dear Haskell community, I have recently written an introductory-level tutorial article about GADTs in GHC (inspired by LASER 2012 summer school and to be submitted to their proceedings). I have already send this draft to the "Haskell Cafe" mailing list, but I was also advised to use these mailing lists, so I would like to ask for your feedback: http://anton-dergunov.ru/publications/gadts_draft_v4.pdf Any opinion about this article and any suggestions are very welcome!

I would like to explore making a backend for .NET. I've done a lot of background reading about previous .NET and JVM attempts for Haskell. It seems like several folks have made significant progress in the past and, with the exception of UHC, I can't find any code around the internet from the previous efforts. I realize that in total it's a huge undertaking and codegen is only one of several significant hurdles to success. I would like to get a very, very, very simple translation working inside GHC. If all I can compile and run is fibonacci, then I would be quite happy. For my first attempt, proof of concept is sufficient. I found a lot of good documentation on the ghc trac for how the compilation phases work and what happens in the different parts of the backend. The documentation is excellent, especially compared to other compilers I've looked at. When I started looking at how to write the code, I started to wonder about the "least effort" path to getting something (anything?) working. Here are some ques

Thanks to John Lato and Duncan Coutts for the latest bugfix release! The latest packages should be buildable on GHC 7.6, and the cairo package should behave a bit nicer in ghci on Windows. Thanks to all!

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