[Haskell-cafe] Haskell User Group Hamburg (Germany) - Meeting Thursday November 8th 2012
Hello cafe, there's an upcomming meeting of the Haskell user group Hamburg next week on Thursday, November 8th. We'll start 19:00 at the fortytools GmbH in Hamburg (Georgsplatz 10, 20099 Hamburg). We don't have a program or talk yet. Maybe we'll discuss our experiences from the last ICFP and the Haskell Symposium. If you are interested to join us, have a look at our doodle (only in german) http://www.doodle.com/gvdsbsyfz7a7427g Be careful: the Google Maps link in the Doodle may direct you to the old address. Georgsplatz 10, 20099 Hamburg is the new one. Further announcements will be made via Twitter, so you may want to follow https://twitter.com/hug_hh. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell User Group Hamburg (Germany) - Meeting Thursday July 12th 2012
Hello cafe, there's an upcomming meeting of the Haskell user group Hamburg next Thursday (July 12th). We'll start 19:00 at the Xing AG in Hamburg (Dammtorstraße 35, 20354 Hamburg ). Jan Ahrens will give a short talk about web development with Yesod ( http://www.yesodweb.com/). Although this announcement is written in english the talk will be given in german. If you are interested to join us, have a look at our doodle (also in german) http://www.doodle.com/5ekivcacuam9czxs Further announcements will be made via Twitter, so you may want to follow https://twitter.com/hug_hh. ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] Haskell User Group Hamburg (Germany) - Meeting Thursday June 14th 2012
Hello cafe, there's an upcomming meeting of the Haskell user group Hamburg next Thursday (June 14th). We'll start 19:00 at the Xing AG in Hamburg (Gänsemarkt 43, 20354 Hamburg). Falko Peters will give a short talk about hedis ( http://hackage.haskell.org/package/hedis), a Redis client written in Haskell. Although this announcement is written in english the talk will be given in german. So if you are interested to come, have a look at our doodle (also in german) and give us a short note if you want to join us. http://www.doodle.com/3fz45uqupp8pzutb Further announcements will be made via Twitter, so you may want to follow https://twitter.com/hug_hh. Stefan Schmidt ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Actors and message-passing a la Erlang
Hi Yves, You say that With the help of this library it is possible to build Erlang-Style mailboxes, but how would you solve the issue of static typing? this wasn't an issue for me because I wanted as much type checking as possible. In many implementations, you have an implicit contract between the sender and the receiver process. In this case, the contract is explicit and the compiler can tell me if I'm trying to send or receive wrong data. Besides, Holumbus depends on package 'unix', preventing it from being used on non-unix platforms. Oh... hmm, I think, the unix-package is only needed for the console-modules. The distribution modules should not need them, but I may be wrong. I don't have access to proprietary plattforms, but I think about splitting the distribution package and extract the communication modules. Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] Actors and message-passing a la Erlang
Hi, I don't know if this solves your problem, but maybe you should take a look at the Holumbus-Distribution package: http://hackage.haskell.org/package/Holumbus-Distribution I've build this library because I needed a simple way to transfer messages between two haskell processes or threads.The current code can be found under Holumbus.Distribution.* especially the DNode and the DStreamPort modules. The modules located under Holumbus.Network are deprecated. Best Regards, Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANN: Holumbus-Distribution 0.1.0 - distributed data structures
Hello, after a long year, I've finally managed to upload the new version of Holumbus-Distribution to Hackage. Holumbus-Distribution offers distributed data structures like Chan, MVar or functions. These data types can be used for inter-process communication. With the help of this library it is possible to build Erlang-Style mailboxes for an easy implementation of distributed systems in Haskell. You can find the library on Hackage at: http://hackage.haskell.org/package/Holumbus-Distribution And the project homepage at: http://www.holumbus.org (for the current documentation please refer to the example programs in the source bundle, the Wiki will be updated soon) The following data structures are implemented so far: * distributed Chan (DChan) like the Chan datatype, but it allows the writing and reading from other programs * distributed MVar (DMVar) like the MVar data type, but the content of the MVar is shared among multiple programs. * distributed Functions (DFunction) an easy way to do remote procedure calls, just like haxr * distributed Values (DValue) a variable which could only be written once and which could easily read by other programs * distributed Streams and Ports (DStream, DPort) just like the DChan, but this time, you are only allowed to read from the channel from one program This library was completely rewritten between version 0.0.1 and 0.1.0. The old packages can be found under Holumbus.Network.* while the new ones are located at Holumbus.Distribution.*. The old packages will be removed in future versions (0.2.0). This library itself is independent from other Holumbus libraries although it contains some modules which are only to be used by the other Holumbus libraries but this may change in the near future. Regards, Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] How to compare PortNumbers or Bug in Network.Socket?
Hello, I want to compare two PortNumber-Values from the Network.Socket module and I think I've experienced some unexpected behavior of the derived ordering methods. I'm using the ghc-6.10.1 and the network library 2.2.0.1 on a x86 32-Bit machine. The following program creates two pairs of PortNumber values and compares them with each other. module Main(main) where import Network.Socket -- Block A p1 :: PortNumber p1 = fromIntegral 9000 p2 :: PortNumber p2 = fromIntegral 1 -- Block B pp1 :: PortNumber pp1 = PortNum 9000 pp2 :: PortNumber pp2 = PortNum 1 main :: IO () main = do putStrLn $ A - ++ (show $ p1 p2) putStrLn $ B - ++ (show $ pp1 pp2) On my machine, I get the result: A - True A - False At the first glance, it seemed to me, that there is a bug in the fromIntegral Implementation. But after I looked into the code, I saw that fromIntegral calls the system function htons to change the byte order from my machine to the network byte order, which on my machine is different. Because of this the values 9000 and 1 are transferred, so that their ordering changes. Block B preservers this ordering, because the Constructor PortNum does not call htons, but since the byte order is wrong, I cannot use pp1 and pp2 to address port 9000 and 1. As a work around, I could convert two PortNumbers back to Int-Values before comparing them, but I think the ordering functions for the PortNumber-Type do not work as expected. Or am I wrong? Stefan Schmidt ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
Re: [Haskell-cafe] How to compare PortNumbers or Bug in Network.Socket?
Philippa Cowderoy wrote: On Thu, 2009-03-12 at 14:56 -0700, Bryan O'Sullivan wrote: However, it's also arguably the case that you shouldn't care about port number ordering. That smells dodgy to me. Port ranges aren't that uncommon. That's exactly were I need the comparison. I'm writing a program which takes a range of port numbers and tries to open a socket with the first available port number. The whole thing is part of a distributed system and I cannot specify just a single port number because I could already been taken. Stefan ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
[Haskell-cafe] ANNOUNCE: Holumbus-MapReduce 0.0.1
The Holumbus framework is known for building specialized search-engines like the Hayoo! Haskell API search. Now, I'd like to announce the newest libraries of the Holumbus framework: Holumbus-MapReduce0.0.1 Holumbus-Distribution 0.0.1 Holumbus-Storage 0.0.1 As part of my Master's Thesis at the University of Applied Sciences in Wedel, Germany, I have developed a library for building distributed MapReduce systems in Haskell. The existing Holumbus-Searchengine library already offers a MapReduce implementation, but it does not provide mechanisms for distributed computing. The newly developed Holumbus-MapReduce library contains of tools and modules for building individualized distributed MapReduce systems. Holumbus-MapReduce is based on two libraries: Holumbus-Distributed and Holumbus-Storage. Maybe they could be useful for building other distributed systems, not only a MapReduce system. Holumbus-Distribution consists of modules and tools for the implementation of distributed systems in general. Besides common data types and small helper functions, this library provides a mailbox-based data transfer mechanism. It offers an easy-to-use interface for inter- and intra-process communication like in Erlang or Mozart/Oz. Holumbus-Storage is designed to build a distributed storage system which can be linked into other programs. It is used by the MapReduce system for the data management. All three libraries are still under heavy development and should not be considered for creating applications in productive environments. But I think, it's time to give them to the community for suggestions on further development and features. Please email comments, bugs, etc. to s...@holumbus.org Stefan Schmidt Holumbus on Hackage: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Holumbus-MapReduce http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Holumbus-Distribution http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Holumbus-Storage link to my thesis: http://www.holumbus.org/redmine/attachments/37/thesis-mapreduce.pdf project homepage: http://www.holumbus.org/redmine/wiki/holumbus darcs repository (latest snapshots): http://holumbus.fh-wedel.de/holumbus/src ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
