- Haskell-Cafe - Haskell.org

quickcheck for compiler testing
by Maurizio Vitale 17 Feb '15

17 Feb '15

I'm starting to work on my first real haskell program (I've only RWH exercises under my belt) and wondering whether people use quickcheck at all for compiler testing. I've seen uses of quickcheck for testing parsers, but I'm interested in generating well-formed programs (e.g. random programs with all declarations in reasonable random places). This could be used to test passes other than parsing (or even parsing, for languages that needs to distinguish identifiers, like the 'typedef' problem in C/C++). The only thing I can think of, is to use quickcheck for randomly generating statements, go over them and figure out free variables (incl. functions) and generate declarations in random places for them. But I'm not sure how this would play with test size reduction and doesn't look like a nice solution anyhow. Any idea or pointers to examples? or should I give up on quickcheck for this and just do direct testing? Thanks, Maurizio

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Haskell Weekly News
by Kim-Ee Yeoh 17 Feb '15

17 Feb '15

Welcome. Here are this week's picks: - Scott Turner <http://ghc.haskell.org/trac/ghc/ticket/8539#comment:25> proffered a solution in getting exponentiation of complex numbers right, which includes an at-a-glance table to see if everything's sane. - GHC is unsound! <https://mail.haskell.org/pipermail/ghc-devs/2015-January/008189.html> It has a type safety leak. Iavor Diatchki <https://mail.haskell.org/pipermail/ghc-devs/2015-February/008269.html> is hard at work plugging the hole. - Richard Eisenberg <https://mail.haskell.org/pipermail/ghc-devs/2015-February/008271.html> discovered that Debug.Trace.traceStack does a better job debugging GHC than pprTrace. - The curtain is pulled back on the new face of www.haskell.org. Chris Done designed it, Gershom Bazerman announced it, and unsung heroes migrated it and kept it running under the flash crowd onslaught. The raves include: - This is far more welcoming and user-friendly, especially to those who might be curious about Haskell. [link] <https://news.ycombinator.com/item?id=9052129#up_9052355> - The website redesign is great from a new programmer's perspective. I just started learning Haskell a week ago, and I wish this was the first thing I saw. Looks wonderful. Cheers! [link] <http://www.reddit.com/r/haskell/comments/2vy1lw/new_haskell_homepage_is_liv…> - This new, awesome site is using the framework Yesod, which is kinda like the Rails of the Haskell world, only it can do rad stuff like prevent XSS and 404s at *compile *time. Yes, you read that right. [link] <https://news.ycombinator.com/item?id=9052129#up_9052279> - Repo of the week: Samuel Gélineau's hawk <https://github.com/gelisam/hawk>, a haskell command-line text-processor similar to unix awk. Quotes of the week: - "I have made several forays into the impredicative swamp, and barely made it back to the shore alive." - Simon Peyton Jones - "Web programming is like a mature RPG: everything's extremely complicated and everyone's overpowered." - Max Goldstein Tweets: - In Buenos Aires, Marcote Torres tweets <https://twitter.com/marcote_torres/status/565644584060198914> about the first ever Haskell meetup. - And "In Soviet Russia, #haskell learns a you" as @aberls <https://twitter.com/aberls/status/565669752853778432> reminds us. Got a letter to the editor? Hit reply. -- Kim-Ee

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Re: [Haskell-cafe] Refactor unqualified imports to qualified ones automatically?
by Jeffrey Brown 17 Feb '15

17 Feb '15

Thank you, Henning. I found a description [1] of what the -ddump-minimal-imports flag you suggest does ("Dump a minimal set of imports"), and I don't know what that means. I tried running it anyway, but I can't get the code to compile via GHC (or make, or cabal install, though it seems to want to be built via at least one of those). It was abandoned long ago, and I'm not convinced its network of dependencies is something I can disentangle. [1] https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/flag-refere… On Sun, Feb 15, 2015 at 1:20 PM, Henning Thielemann < lemming(a)henning-thielemann.de> wrote: > > Maybe the GHC flag > > -ddump-minimal-imports > > helps? >

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HaskBoard?
by Mike Meyer 16 Feb '15

16 Feb '15

I asked about running GHCI on something like the Arduino due, and was told that there wasn't enough CPU on it for that. How about getting it running on something like a PyBoard? http://www.adafruit.com/products/2390

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New Functional Programming Job Opportunities
by Functional Jobs 16 Feb '15

16 Feb '15

Here are some functional programming job opportunities that were posted recently: Senior Developer (Big Data Tech Stack) at Recruit IT Group Ltd http://functionaljobs.com/jobs/8783-senior-developer-big-data-tech-stack-at… Senior Development Engineer at Lookingglass Cyber Solutions http://functionaljobs.com/jobs/8782-senior-development-engineer-at-lookingg… Cheers, Sean Murphy FunctionalJobs.com

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Is there a cross platform CA certificate bundle solution for HsOpenSSL?
by Marios Titas 16 Feb '15

16 Feb '15

If I want to use HsOpenSSL for a tls client application that verifies the server certificate I have to manually specify a CA certificate bundle containing the trusted roots. For example, in a linux system, I would do the following mkTlsContext :: IO Context mkTlsContext = do ctx <- context contextSetVerificationMode ctx (VerifyPeer True False Nothing) contextSetCADirectory ctx "/etc/ssl/certs" return ctx The problem is that the above solution only works for linux. Is there a cross-platform way to find a reasonable CA bundle and use it with HsOpenSSL? Note that the tls package has x509-system [1] that does exactly that. So I am basically asking if anybody has written something similar for HsOpenSSL. [1] https://hackage.haskell.org/package/x509-system

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Cancelled: Re: Typed TH
by Gautier DI FOLCO 16 Feb '15

16 Feb '15

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Événement annulé: Re: Typed TH - Lun. 16 Févr. 2015 09:00 - 10:00 (gautier.difolco@gmail.com)
by gautier.difolco＠gmail.com 16 Feb '15

16 Feb '15

Cet événement a été annulé et supprimé de votre agenda. Titre : Re: [Haskell-cafe] Typed TH Date : Lun. 16 Févr. 2015 09:00 - 10:00 Paris Agenda : gautier.difolco(a)gmail.com Participants : * Gautier DI FOLCO- organisateur * haskell-cafe * ben.franksen(a)online.de Invitation de Google Agenda : https://www.google.com/calendar/ Vous recevez ce message à l'adresse haskell-cafe(a)haskell.org, car vous participez à cet événement. Pour ne plus recevoir de notifications pour cet événement à l'avenir, refusez cet événement. Vous avez également la possibilité de créer un compte Google sur la page https://www.google.com/calendar/ et de définir vous-même les paramètres de notification pour l'intégralité de votre agenda.

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Invitation: Re: Typed TH - Lun. 16 Févr. 2015 09:00 - 10:00 (Gautier DI FOLCO)
by Gautier DI FOLCO 16 Feb '15

16 Feb '15

Vous avez été invité à l'événement suivant. Titre : Re: [Haskell-cafe] Typed TH Date : Lun. 16 Févr. 2015 09:00 - 10:00 Paris Agenda : Gautier DI FOLCO Participants : * Gautier DI FOLCO- organisateur * haskell-cafe * ben.franksen(a)online.de Détails de l'événement : https://www.google.com/calendar/event?action=VIEW&eid=XzcxaTNhZTFtY2RqM2diY… Invitation de Google Agenda : https://www.google.com/calendar/ Vous recevez ce message à l'adresse haskell-cafe(a)haskell.org, car vous participez à cet événement. Pour ne plus recevoir de notifications pour cet événement à l'avenir, refusez cet événement. Vous avez également la possibilité de créer un compte Google sur la page https://www.google.com/calendar/ et de définir vous-même les paramètres de notification pour l'intégralité de votre agenda.

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Typed TH
by Christopher Done 16 Feb '15

16 Feb '15

http://lpaste.net/116791 If someone feels like spending time exploring this and putting it in a library I will be interested in trying it. I saw some old work to patch GHC to do this including typed quotation of expressions, which doesn't seem to have arrived. Relatedly I made a trivial Lisp with untyped and typed quotation https://gist.github.com/chrisdone/516489f4f27846712225 It doesn't seem to be a much-explored area in the Lisp world, Haskell is treading new waters in some ways.

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