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Building PanDoc for iOS target,but failed in Haskell Template requirement by 'aeson' package

haskell-cafe - Mon, 12/23/2013 - 1:51pm
Hi, I've been trying to cross-compile PanDoc for iOS target for the last few days. I have been quite successfull from building stage-1 GHC for iOS target and many packages dependencies required by PanDoc until I see that 'aeson' package require Haskell Template which is not supported in cross compilation. As pointed in iOS CrossCompiling Wiki page, it seems that Template Haskell doesn't work yet and still in wish list. Is there any hack or workaround to be able to cross-compile 'aeson' package for iOS target? Can I compile 'aeson' without Haskell Template? Anybody know when Template Haskell in CrossCompiling for iOS will be added? Thanks a lot! Best regards, Joe_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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[ANN] Laborantin: experimentation framework

haskell-cafe - Mon, 12/23/2013 - 11:27am
Dear all, I am happy to announce Laborantin. Laborantin is a Haskell library and DSL for running and analyzing controlled experiments. Repository: Hackage page: Laborantin's opinion is that running proper experiments is a non-trivial and often overlooked problem. Therefore, we should provide good tools to assist experimenters. The hope is that, with Laborantin, experimenters will spend more time on their core problem while racing through the menial tasks of editing scripts because one data point is missing in a plot. At the same time, Laborantin is also an effort within the broad open-science movement. Indeed, Laborantin's DSL separates boilerplate from the actual experiment implementation. Thus, Laborantin could reduce the friction for code and data-reuse. One family of experiments that fit well Laborantin are benchmarks with tedious setup and teardown procedures (for instance starting, configuring, and stop
Categories: Offsite Discussion

New Functional Programming Job Opportunities

haskell-cafe - Mon, 12/23/2013 - 9:00am
Here are some functional programming job opportunities that were posted recently: Chief Data Scientist at Lazada Cheers, Sean Murphy
Categories: Offsite Discussion

Excellent bikeshedding opportunity! Frontend syntax for pattern synonym types

glasgow-user - Sun, 12/22/2013 - 4:09pm
Hi, As part of my work to add pattern synonyms to GHC ( I initially planned to postpone implementing type signatures ( However, since adding the feature in the first place requires Haddock support, some syntax will be needed for pattern synonym type signatures so that at least there's something to generate into the docs. The basic problem with pattern synonyms in this regard is that their type is fully described by the following five pieces of information: 1, Universially bound type variables 2, Existentially bound type variables 3, The (tau) type itself 4, Typeclass context required by the pattern synonym 5, Typeclass context provided by the pattern synonym To give you some parallels, functions are described by (1), (3) and (4), e.g. given the following definition: f = map fromIntegral (1) is {a, b} (3) is [a] -> [b] (4) is (Integral a, Num b) Data constructors are described by (1), (2), (3) and (5
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Adding a finalizer to a TVar

libraries list - Sun, 12/22/2013 - 2:56pm
Hi, Both MVar and IORef have specialized functions to attach a finalizer to there inner identifiable (stable) reference cell. I happen to need something similar for TVars, but that one doesn't seem to exist. The documentation of System.Mem.Weak tells me: "Finalizers can be used reliably for types that are created explicitly and have identity, such as IORef and MVar. However, to place a finalizer on one of these types, you should use the specific operation provided for that type, e.g. mkWeakIORef and addMVarFinalizer respectively (the non-uniformity is accidental). These operations attach the finalizer to the primitive object inside the box (e.g. MutVar# in the case of IORef), because attaching the finalizer to the box itself fails when the outer box is optimised away by the compiler." Does it make sense to add a similar function to the STM package? What I do now is hack around it by adding an IORef next to my TVar which I attach the finalizer to. Because my outer datatype is opaque I expect both variab
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Troubleshooting-type questions

haskell-cafe - Sat, 12/21/2013 - 1:30am
I wouldn't want to clutter the list with off-topic stuff, so I'll ask first. Once in a while I'll have trouble trying to use some piece of software, like Shpider or Yesod. Is it on-topic to ask specific "how-do-I-use/do"-type questions for particular packages like that on this list? -- Lucas Paul
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Haskell Job Opportunity

haskell-cafe - Sat, 12/21/2013 - 12:43am
AlephCloud is an early stage Silicon Valley startup creating a secure cloud content management system. Haskell is our main server side language and we are looking to hire a few more Haskell programmers. Some topics of interest to us are: cloud services, cryptography/security, cross compilation (javascript, iOS, ARM). We are somewhat flexible about location, though we¹d prefer people on the west coast of the US. If interested feel free to contact me (jeff< at > for more information, or send a message (and/or a resume) to resume< at > thanks, Jeff
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CFP - Rewriting Techniques for Program Transformations and Evaluation 2014

General haskell list - Fri, 12/20/2013 - 11:30pm
CALL FOR PAPERS First International Workshop on Rewriting Techniques for Program Transformations and Evaluation (WPTE'14) affiliated with RTA/TLCA 2014 (a FLoC 2014 workshop, FLoC is part of the Vienna Summer of Logic 2014) 13th July 2014, Vienna, Austria Aims and Scope ============== The aim of WPTE is to bring together the researchers working on program transformations, evaluation, and operationally based programming language semantics, using rewriting methods, in order to share the techniques and recent developments and to exchange ideas to encourage further activation of research in this area. Topics of interest and in the scope of WPTE are: * Correctness of program transformations, optimizations and translations. * Program transformations for proving termination, confluence and other properties. * Correctness of
Categories: Incoming News

Call for Papers: ITP 2014

General haskell list - Fri, 12/20/2013 - 12:10pm
Call for Papers ITP 2014 5th International Conference on Interactive Theorem Proving 14th-17th July 2014 in Vienna, Austria IMPORTANT DATES Abstract submission: 24th January 2014 Paper submission: 31st January 2014 Author notification: 21st March 2014 Camera-ready: 18th April 2014 Conference: 14th-17th July 2014 CONFERENCE BACKGROUND ITP is the premier international conference for researchers from all areas of interactive theorem proving and its applications. It represents the natural evolution of the TPHOLs conference series to include research related to all other interactive theorem provers. TPHOLs meetings took place every year from 1988 until 2009. In 2010, the first ITP conference was held in Edinburgh, Scotland, as part of the Federated Logic Conference (FLoC). Subsequent ITP conferences were held in Nijmegen, The Netherlands, in 2011
Categories: Incoming News

Haskell Weekly News: Issue 288

General haskell list - Fri, 12/20/2013 - 6:02am
Welcome to issue 288 of the HWN, an issue covering crowd-sourced bits of information about Haskell from around the web. This issue covers the week from December 08 to 14, 2013. Quotes of the Week * nlogax: With FRP.Sodium and Graphics.UI.GLUT you could put together a MonadSodium GLUTamate Top Reddit Stories * The reason why `cabal update` takes so long Domain:, Score: 175, Comments: 89 On Reddit: [1] Original: [2] * structured-haskell-mode ­— Structured editing minor mode for Haskell in Emacs Domain:, Score: 103, Comments: 37 On Reddit: [3] Original: [4] * Amazing LVars talk by Linsey Kuper Domain:, Score: 86, Comments: 20 On Reddit: [5] Original: [6] * 24 Days of Hackage: acid-state Domain:, Score: 84, Comments: 15 On Reddit: [7]
Categories: Incoming News

memory ordering

glasgow-user - Fri, 12/20/2013 - 3:36am
Hello, I'm working on a lock-free algorithm that's meant to be used in a concurrent setting, and I've run into a possible issue. The crux of the matter is that a particular function needs to perform the following: and the algorithm is only safe if these two reads are not reordered (both the vector and IORef are written to by other threads). My concern is, according to standard Haskell semantics this should be safe, as IO sequencing should guarantee that the reads happen in-order. Of course this also relies upon the architecture's memory model, but x86 also guarantees that reads happen in order. However doubts remain; I do not have confidence that the code generator will handle this properly. In particular, LLVM may freely re-order loads of NotAtomic and Unordered values. The one hope I have is that ghc will preserve IO semantics through the entire pipeline. This seems like it would be necessary for proper handling of exceptions, for example. So, can anyone tell me if my worries are unfounded, or i
Categories: Offsite Discussion

Job opportunities at Galois Inc.

haskell-cafe - Thu, 12/19/2013 - 7:34pm
Hello, Galois is still hiring! We are located in beautiful Portland, Oregon and are currently looking for researchers, principal investigators, and software engineers, including those with expertise in functional programming, formal methods, computer security, control systems, informatics, or networking. For more information, take a look at and please feel free to drop me an e-mail if you have questions. Happy Holidays, -Iavor _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
Categories: Offsite Discussion

Abstracting configuration directories

haskell-cafe - Thu, 12/19/2013 - 5:46am
I'm writing a small utility whose only non-portable code involves the two paths, /etc/htsnrc $HOME/.htsnrc These have sort-of analogues under Windows; in .NET they are available through something like, Environment.SpecialFolder.CommonApplicationData Environment.SpecialFolder.ApplicationData I personally will only ever need to run on Linux, but as a matter of principle I'd like to abstract the paths. Is there a library that can do this already?
Categories: Offsite Discussion

Persisting a Map

haskell-cafe - Thu, 12/19/2013 - 2:58am
I have a Map. It's a lovely Map, with keys and values and everything. It's not _that_ large. Few 10s of MB at most. Unfortunately, I need to persist it somewhat reliably. I'd somewhat like to avoid having to use an external database (obviously a key/value store like Riak would work, but that's a major dependency to impose on the system) so I'm wondering if there is a low tech way to do this. I can control concurrent access to the file (or whatever), and the file system is robust. So that part is fine. I just need to externalize the map. I'm wondering if just using cereal or so would be sufficient (there is a Serialize instance, of course), or whether I should be using some acid-state thing, or a Haskell binding to gdbm, or sqlite, or... Any suggestions? AfC Sydney
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Decomposition of given equalities

glasgow-user - Thu, 12/19/2013 - 1:38am
Hello, The upcoming GHC 7.8 recently gave me this error: Could not deduce (i ~ i1) from the context (f1 i ~ f i1) Which is strange to me: shouldn't (f1 i ~ f i1) exactly imply (f1 ~ f, i ~ i1)? (Or with nicer variable names: (f a ~ g b) => (f ~ g, a ~ b)?) When I inquired about this in #haskell on IRC, a person going by the name xnyhps had this to say: and later: I'm not quite so well versed in the workings of GHC's type checker as she or he is, but I don't understand why it's this way either. Is this a relic of and Is there a principled reason this shouldn't be true? Is it an intentional limitation of the constraint solver? Or is it just a bug? Thanks in advance, Gábor P.S. I got the error on this line:, possibly after having added kind annotations to `InnerEq` (which also gets a less general kind inferred than the one I expect). If
Categories: Offsite Discussion

ANNOUNCE: Ajhc Haskell Compiler Release

haskell-cafe - Wed, 12/18/2013 - 7:07pm
We are happy to announce Ajhc as Christmas release! You can get Ajhc using "cabal install drift && cabal install ajhc" command. The usage is found at Ajhc's project web site The source code at Welcome sending any bugs or your ideas to ## News ### Android demo Android demo application using Haskell is available at Google Play. ### Clear license notification * Runtime: [MIT License]( * Haskell libraries: [MIT License]( * The others: [GPLv2 or Later]( ## Other changes * Depend on DrIFT again / Do not need derive * Fix GC root BUG * Use findExecutable instead of the raw `which` * Come back bytestring * And fix other BUGs Enjoy! :) - - - Metasepi team
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Haskell Singapore Meetup

haskell-cafe - Wed, 12/18/2013 - 12:12pm
Hi all, I've already posted on the reddit but forgot to post it here. It's going to be Christmas, and a good way to celebrate it is to have a Haskell meetup. On this Friday, Dec 20. We are going to host it at Google Singapore office. There would be a short sharing and have some time to meet with other Haskell programmers (or FP programmer in general) after the talk. If you happen to be in Singapore, welcome to stop by! For people signed up before, notice that we are moving from Zalora to Google's office to have a bigger meeting room. And due to the access policy, please fill out your full name, e-mail and company in the following form. Paul Meng _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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glasgow-user - Wed, 12/18/2013 - 11:08am
The documentation for --split-objs states that "this only makes sense for libraries". How is an executable compiled against a split-objs library? According to, this isn't happening by default. -- View this message in context: Sent from the Haskell - Glasgow-haskell-users mailing list archive at
Categories: Offsite Discussion

SYB supports genuine gmap. [Was: Polymorphicupdating with TC/TFs?]

haskell-cafe - Wed, 12/18/2013 - 11:06am
adam vogt wrote SYB supports the type-changing generic map, of the signature It was discovered back in 2008. Please see the following thread starting The fake described in haskellwiki/SYB#fmap with unsafeCoerce is not needed at all. There is a genuine gmap.
Categories: Offsite Discussion

Haskell and Big Data

haskell-cafe - Wed, 12/18/2013 - 9:41am
Hello Cafe, Big Data is a bit trendy these days. Does anybody know about plans to develop an Haskell eco-system in that domain? I.e tools such as Storm or Spark (possibly on top of Cloud Haskell) or, at least, bindings to tools which exist in other languages. Thank you Regards J-C _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe< at >
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