August 2014 - Haskell-Cafe

http://www.downforeveryoneorjustme.com/haskell.org
by Tim C. Schroeder 03 Aug '14

03 Aug '14

Thinks always break on the weekend, don’t they! Apologies if this is a scheduled outtake. In the meantime, there’s fortunately a Haddock mirror on http://haddocks.fpcomplete.com/fp/7.7/20131212-1/ ;-) Cheers, Tim

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Haskell Platform 2014.2.0.0 Release Candidate 4 (Windows only)
by Mark Lentczner 02 Aug '14

02 Aug '14

This is an update to the Windows RC2 candidates. These candidates fix three problems with the installation scripts. The binary build of the packages has not changed. *Fixes:* - Fix the PATH to add the location where binaries are installed with "cabal install --global" - Fix the url shortcut that is installed, to point to the platform+ghc master indices, rather than just the ghc indices - Fix where a 32-bit HP installed on a 64-bit system was going *Installers can be found here:* - HaskellPlatform-2014.2.0.0-i386-RC4-setup.exe <http://www.ozonehouse.com/mark/platform/HaskellPlatform-2014.2.0.0-i386-RC4…> - HaskellPlatform-2014.2.0.0-x86_64-RC4-setup.exe <http://www.ozonehouse.com/mark/platform/HaskellPlatform-2014.2.0.0-x86_64-R…> - Mark P.S.: You might have noticed that the server that hosted the RC files was down intermittently yesterday and today. It suffered a double (!) disk failure. It is back up with shiny new disks. P.P.S: As always, for the reasonably wary: shasum -a 256: 975e014d53cfdb84036889923d6e9598e4623baa9c69d53dc4d9372fe100cf95 HaskellPlatform-2014.2.0.0-i386-RC4-setup.exe 05b39901cdc43de335583c461bcd77c0d8dd5765ab195ad387a0dc774a43bee2 HaskellPlatform-2014.2.0.0-x86_64-RC4-setup.exe

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unfoldr with a little extra
by David Feuer 02 Aug '14

02 Aug '14

Edward Kmett's NonEmpty module has a version of unfoldr (there just called unfoldr) for non-empty lists that seems also to be useful when applied to regular lists: unfoldr1::(b -> (a, Maybe b)) -> b -> [a] unfoldr1 f b= go b where go q = case f q of (a,may_b) -> a : maybe [] go may_b My question is whether it is possible to write this function using the usual unfoldr. I have the feeling there might be some way, but I just can't see it. David

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typed tagless-final interpretation examples broken with recent ghc
by Mathijs Kwik 02 Aug '14

02 Aug '14

Hi all, I've been reading up on typed tagless-final interpretations [1] and the accompanying examples. It seems the stuff about CPS transformations does no longer compile, probably because of stricter typing rules. I tried both ghc 7.6 and ghc 7.8, which both give a different kind of error message. It's a bit much and long to paste here though. I would really like to get the example working, but couldn't manage by only supplying type signatures. Perhaps there is some language pragma I can turn on or off to get the old behaviour back? The 2 files needed (no further libraries needed) are: - http://okmij.org/ftp/tagless-final/course/TTF.hs (working) - http://okmij.org/ftp/tagless-final/course/CPS.hs (problem) All help would be greatly appreciated. Regards, Mathijs [1] http://okmij.org/ftp/tagless-final/course/index.html

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re-reading a Samson Abramsky paper ..
by Vasili I. Galchin 02 Aug '14

02 Aug '14

http://staff.science.uva.nl/~ssimon/indjournal/pdf/abramsky.pdf .. no words .. I will let Samson speak for himself .. :-) Hopefully my audience cam keep up with Abramsky's terseness .. he is very "cheeky" ...

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Re: [Haskell-cafe] Tor project
by Adam Wick 01 Aug '14

01 Aug '14

Hi - Yes, we (Galois) are. The end goal is to have a Tor implementation running on a HaLVM. Right now the project is internal, but the plan is to push a basic relay node implementation out to our GitHub site sometime in the next few weeks. As for TLS, it is possible that timing attacks based on a functional language implementation could be more likely than those for a traditional C implementation. On the other hand, functional language implementations protect you from a wide variety of attacks that occur in C implementations. I don’t believe the balance has been studied, but it’d be interesting. I do know the OCaml/Mirage folks have been having good luck with their TLS implementation. I believe they’ve at least started doing some red team analysis of it, as well, with good results. See their various blog posts, starting with http://openmirage.org/blog/introducing-ocaml-tls. I’m not sure if Vincent’s library has been subject to similar evaluation, and I know the partial library in our Tor implementation has not been. - Adam Quoth: > I’ll make a question out of it: > > Is anyone working on a Haskell project compatible with Tor? Library, Server, Browser, etc. > Is anyone interested in such a project? > Would the Haskell Runtime and TLS modules have any time dependent behavior that would make encryption harder/easier to break than C implementations? Basically, is the TLS attach surface smaller or larger than openssl and is there any data to support claims of such?

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EsseOS: Haskell-based tailored services for the cloud
by Vo Minh Thu 01 Aug '14

01 Aug '14

Hi, I came across this seemingly interesting paper: EsseOS: Haskell-based tailored services for the cloud http://dl.acm.org/citation.cfm?id=2541587 which is unfortunately behind a paywall. I was wondering if someone knew about a freely accessible version of that paper, or about some project page, or just heard of it. Thank you, Thu

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ICFP 2014 Final Call for Participation
by David Van Horn 01 Aug '14

01 Aug '14

[ Early registration ends 3 Aug; Invited speakers and conference program have been announced. ] ===================================================================== Final Call for Participation ICFP 2014 19th ACM SIGPLAN International Conference on Functional Programming and affiliated events August 31 - September 6, 2014 Gothenburg, Swedenhttp://icfpconference.org/icfp2014/ ===================================================================== ICFP provides a forum for researchers and developers to hear about the latest work on the design, implementations, principles, and uses of functional programming. The conference covers the entire spectrum of work, from practice to theory, including its peripheries. A full week dedicated to functional programming: 1 conference, 1 symposium, 10 workshops, tutorials, programming contest results, student research competition * Program: http://icfpconference.org/icfp2014/program.html * Accepted Papers: http://icfpconference.org/icfp2014/accepted.html * Local arrangements (including travel and accommodation): http://icfpconference.org/icfp2014/local.html * Registration is available via: https://regmaster4.com/2014conf/ICFP14/register.php Early registration is due 3 August, 2014. * Programming contest, 25-28 July, 2014: http://icfpcontest.org/ * Follow @icfp_conference on twitter for the latest news: http://twitter.com/#!/icfp_conference Keynote speakers: * Kathleen Fisher (Tufts University): Using Formal Methods to Enable More Secure Vehicles: DARPA's HACMS Program * Robert Bruce Findler (Northwestern University): Behavioral Software Contracts * Stephanie Weirich (University of Pennsylvania): Depending on Types There are several events affiliated with ICFP: Sunday, August 31 ACM SIGPLAN Workshop on Generic Programming ACM SIGPLAN Workshop on Higher-order Programming with Effects Monday, September 1 – Wednesday, September 3 ICFP Thursday, September 4 ACM SIGPLAN Commercial Users of Functional Programming: Day 1, Tutorials ACM SIGPLAN Haskell Symposium: Day 1 ACM SIGPLAN Workshop on Functional High-Performance Computing ACM SIGPLAN ML Family Workshop Friday, September 5 ACM SIGPLAN Commercial Users of Functional Programming: Day 2, Tutorials ACM SIGPLAN Haskell Symposium: Day 2 ACM SIGPLAN OCaml Workshop ACM SIGPLAN Erlang Workshop Saturday, September 6 ACM SIGPLAN Commercial Users of Functional Programming: Day 3, Talks ACM SIGPLAN Haskell Implementors Workshop ACM SIGPLAN Workshop on Functional Art, Music, Modeling and Design Conference Organizers General Chair: Johan Jeuring, Utrecht University Program Chair: Manuel Chakravarty, University of New South Wales Local Arrangements Chair: Björn von Sydow, Chalmers University Industrial Relations Chair: Anil Madhavapeddy, University of Cambridge Workshop Co-Chairs: Tom Schrijvers, Ghent University Sam Tobin-Hochstadt, Indiana University Programming Contest Co-Chairs: Duncan Coutts, Well Typed LLP Nicolas Wu, University of Oxford Student Research Competition Chair: Meng Wang, Chalmers University Publicity Chair: David Van Horn, University of Maryland Video Chair: Iavor Diatchki, Galois Malcolm Wallace, Standard Chartered Bank Industrial partners: Platinum partners Jane Street Capital Gold partners Google Microsoft Research Mozilla Oracle Labs Standard Chartered Bank Silver partners Bloomberg Credit Suisse CyberPoint Erlang Solutions Facebook Galois Klarna Lexifi Twitter Bronze partners Alephcloud IntelliFactory Opera Software QuviQ Systeor Vest AS =====================================================================

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haskell on Debian
by Kees Bleijenberg 01 Aug '14

01 Aug '14

I want to reinstall Haskell on Debian (in Virtualbox on Windows). So: apt-get remove haskell-platform Deleted all maps with packages in it. apt-get install haskell-platform (installing previous selected ... etc) cabal update All this without errors of warnings. cabal install cabal-install Error: /var/lib/ghc/package.conf.d: openFile: does not exist Why this error? Setup doesn't create this directory?

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Tor project and Haskell (FPL) ,..
by Vasili I. Galchin 01 Aug '14

01 Aug '14

I wasn't trying to offend anybody .... Only trying to provoke a lively discussion in order lift all boats. Sometimes one sentence IHMO provokes thought. In any case I appreciate all responders :-) Kind thanks friends. Vasya

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