- Haskell-Cafe - Haskell.org

ANN: ssh, darcsden vulnerability
by Simon Michael 20 Apr '15

20 Apr '15

We recently learned of a serious undocumented vulnerability in the ssh <http://hackage.haskell.org/package/ssh> package. This is a minimal ssh server implementation used by darcsden <http://hackage.haskell.org/package/darcsden> to support darcs push/pull. If you use the ssh package, or you have darcsden’s darcsden-ssh server running, you should upgrade to/rebuild with the imminent ssh-0.3 release right away. Or if you know of someone like that, please let them know. Also, if you're interested in cryptography/security, additional help and patches for the ssh and darcsden packages would be very welcome. I've blogged more details at http://joyful.com/blog/2015-04-20-ssh-darcs-hub-vulnerability.html <http://joyful.com/blog/2015-04-20-ssh-darcs-hub-vulnerability.html> (if you're a Darcs Hub user, hopefully you've already seen it). Best - Simon

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Attempt to emulate subclasses in Haskell, am I reinventing the wheel?
by Clinton Mead 20 Apr '15

20 Apr '15

I've linked to an ugly attempt to emulate subclasses in Haskell, and I'm wondering if anyone has done what I have perhaps in a cleaner way. Firstly, the code is here: http://ideone.com/znHfSG To explain what I've done, I first thought that a "method" basically takes some "input" (which I've called "i"), an object (which I've called "c" for class) and returns some output "o" and a potentially modified object "c". I've captured this behaviour in the badly named class "C". I've then made a class "User", with methods "getFirstName" and "putFirstName" and defined them appropriately. Furthermore, I've then made a data type "Age", and then "ExtendedUser" which combines "User" with "Age". At this point, I can still call "getFirstName" and "putFirstName" on "ExtendedUser", as would be hoped. I also defined "getAge", which naturally works on ExtendedUser. Furthermore, I can override "getFirstName" on "ExtendedUser", which I have done to instead return a capitalised version. Is what I've done of any practical use? And has someone done it better than me?

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Fall Internship Opportunities at Galois
by Ryan Wright 20 Apr '15

20 Apr '15

Galois has some exciting opportunities for interns in software engineering/research for the Fall of 2015. Most of our projects use Haskell to some extent, so this is a great chance to get experience applying functional programming to important real-world problems. Please pass along this posting to anyone you think might be interested--even if they don't yet know Haskell! Thank you, Ryan Wright — # Galois Software Engineering/Research Intern # Galois is currently seeking software engineering and research interns for Fall 2015 at all educational levels. We are committed to matching interns with exciting and engaging engineering work that fits their particular interests, creating lasting value for interns, Galois, and our community. A Galois internship is a chance to tackle cutting-edge, meaningful problems in a uniquely collaborative environment with world-leading researchers. Roles may include technology research and development, requirements gathering, implementation, testing, formal verification, and infrastructure development. Past interns have integrated formal methods tools into larger projects, built comprehensive validation suites, synthesized high-performance cryptographic algorithms, written autopilots for quad-copters, designed the syntax and semantics of scripting languages, and researched type system extensions for academic publication. We deeply believe in providing comprehensive support and mentorship to all of our employees, particularly interns. We provide our employees with a steward who regularly checks in to ensure that they feel welcome and safe in the Galois community while gaining real value from their experiences. ## Important Dates ## Applications due: June 1st, 2015 Internship period (flexible): September through December, 2015 ## About Galois ## Our mission is to create trustworthiness in critical systems. We’re in the business of taking blue-sky ideas and turning them into real-world technology solutions. We’ve been developing real-world systems for over ten years using functional programming, language design, and formal methods. Galois values diversity. We believe that differing viewpoints and experiences are essential to the process of innovation. We look broadly, including outside of established communities, to deliver innovation. ## How to Prepare ## An internship is an opportunity for learning and growth as an engineer. To make the most of the opportunity, we ask that candidates have experience reading, writing, and maintaining code in a realistic project. Many university courses involve multi-week collaborative projects that provide this type of experience. Most of our projects use the Haskell programming language and the git version control system. These tools aren’t often taught in computer science classes, but there are many free resources available that we recommend for learning: - [Learn You a Haskell] for Great Good! [1] by Miran Lipovača - [Real World Haskell] [2] by Bryan O’Sullivan, Don Stewart, and John Goerzen - [tryGit] [3] by Code School - [Pro Git] [4] by Scott Chacon [1]: http://learnyouahaskell.com/ [2]: http://book.realworldhaskell.org/ [3]: http://try.github.io [4]: http://git-scm.com/book ## Qualifications ## The ability to be geographically located in Portland during the internship Experience reading, writing, and maintaining code in a project as described above Proficiency in software development practices such as design, documentation, testing, and the use of version control Well-developed verbal and written communication skills; comfort in a collaborative team environment The following skills are not required, but may be relevant to a particular project. - Proficiency in Haskell or other programming languages with rich type systems (eg., Scala, OCaml, Standard ML) - Experience using C and assembly languages for low-level systems programming - Development experience in high assurance systems or security software - Specific experience in an area of Galois’ expertise, such as: - Assured information sharing - Software modeling and formal verification - Cyber-physical systems and control systems - Operating systems, virtualization and secure platforms - Networking and mobile technology - Cyber defense systems - Scientific computing - Program analysis and software evaluation - Web security ## Logistics ## The length and start date of the internship are negotiable: starting any time from the new year through next spring is acceptable, but an intern must be at Galois for at least three continuous months. The internship is paid competitively, and interns are responsible for living arrangements (although we can certainly help you find arrangements). Galois is located in the heart of downtown Portland with multiple public transportation options available and world-class bicycle infrastructure. ## Application Details ## We’re looking for people who can invent, learn, think, and inspire. We reward creativity and thrive on collaboration. If you are interested, please send your cover letter and resume to us via http://galois-inc.hiringthing.com.

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New Functional Programming Job Opportunities
by Functional Jobs 20 Apr '15

20 Apr '15

Here are some functional programming job opportunities that were posted recently: Mid/Senior Software Development Engineer at Lookingglass Cyber Solutions http://functionaljobs.com/jobs/8810-mid-senior-software-development-enginee… Senior/Principal Software Development Engineer at Lookingglass Cyber Solutions http://functionaljobs.com/jobs/8809-senior-principal-software-development-e… Cheers, Sean Murphy FunctionalJobs.com

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Maintenance of feed package
by Adam Bergmark 20 Apr '15

20 Apr '15

Hi café, Sigbjorn. I emailed Sigbjorn a week ago asking whether he was still maintaining the `feed' package. I haven't received a reply, and I haven't been able to find any sign of him online recently. Unless he resurfaces I'd like to take over as maintainer of the package to publish the changes required for GHC 7.10 compatibility and other dependencies that have fallen out of date. See: https://github.com/sof https://github.com/sof/feed/pulls https://github.com/haskell-infra/hackage-trustees/issues/12 Regards, Adam

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ANN: hsreadability-1.0.0
by Alexey Shmalko 19 Apr '15

19 Apr '15

I'm pleased to announce the first release of hsreadability: Haskell bindings to the Readability API [1]. The Readability provides three services for developers: Reader, Parser and Shortener: - Reader provides access to the user's info, bookmarks, articles and tags; - Parser is an interface to the powerful web content parser; - Shortener is a URL shortener (doesn't require authentication). With hsreadability you're able to access all the functionality of these services from Haskell. If you have any issues, report them on the GitHub page [2]. I'd also love to hear any other feedback so feel free to comment here or email me. Best regards, Alexey Shmalko [1] https://readability.com/developers/api [2] https://github.com/rasendubi/hsreadability

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Scala at position 25 of the Tiobe index, Haskell dropped below 50
by Henk-Jan van Tuyl 19 Apr '15

19 Apr '15

L.S., From the Tiobe index page[0] of this month: Another interesting move this month concerns Scala. The functional programming language jumps to position 25 after having been between position 30 and 50 for many years. Scala seems to be ready to enter the top 20 for the first time in history. Haskell dropped from the top 50 last month and hasn't come back. I suppose, if Haskell compiled to JVM, Haskell would have a much wider audience. Regards, Henk-Jan van Tuyl [0] http://www.tiobe.com/index.php/content/paperinfo/tpci/index.html -- Folding@home What if you could share your unused computer power to help find a cure? In just 5 minutes you can join the world's biggest networked computer and get us closer sooner. Watch the video. http://folding.stanford.edu/ http://Van.Tuyl.eu/ http://members.chello.nl/hjgtuyl/tourdemonad.html Haskell programming --

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dependency issues on a new install of haskell-platform 2014.2.0.0 64bit on OSX
by Anatoly Yakovenko 18 Apr '15

18 Apr '15

so I keep seeing failures in some modules, but if i install them by hand things get resolved. How do i get cabal to do this for me? so the dependencies: criterion -> monad-par-0.3.4.7 -> parallel-3.2.0.4 which fails but installing parallel-3.2.0.6 unravels the broken dependency chain. Below is the output: cabal: Error: some packages failed to install: criterion-1.1.0.0 depends on monad-par-0.3.4.7 which failed to install. monad-par-0.3.4.7 failed during the building phase. The exception was: ExitFailure 1 statistics-0.13.2.3 depends on monad-par-0.3.4.7 which failed to install. anatolys-MacBook:rbm anatolyy$ cabal install monad-par Resolving dependencies... Configuring monad-par-0.3.4.7... Building monad-par-0.3.4.7... Failed to install monad-par-0.3.4.7 Last 10 lines of the build log ( /Users/anatolyy/.cabal/logs/monad-par-0.3.4.7.log ): Building monad-par-0.3.4.7... Preprocessing library monad-par-0.3.4.7... <command line>: cannot satisfy -package-id parallel-3.2.0.4-c330f8c64fe6816637464ee78fcb9a93 (use -v for more information) cabal: Error: some packages failed to install: monad-par-0.3.4.7 failed during the building phase. The exception was: ExitFailure 1 anatolys-MacBook:rbm anatolyy$ cabal install parallel Resolving dependencies... Downloading parallel-3.2.0.6... Configuring parallel-3.2.0.6... Building parallel-3.2.0.6... Installed parallel-3.2.0.6 Updating documentation index /Users/anatolyy/Library/Haskell/share/doc/index.html anatolys-MacBook:rbm anatolyy$ cabal install monad-par Resolving dependencies... Configuring monad-par-0.3.4.7... Building monad-par-0.3.4.7... Installed monad-par-0.3.4.7 Updating documentation index /Users/anatolyy/Library/Haskell/share/doc/index.html

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Re: [Haskell-cafe] Graph diagram tools?
by Ivan Lazar Miljenovic 17 Apr '15

17 Apr '15

Wow, you really have resurrected an old thread! On 17 April 2015 at 03:12, Ivan Zakharyaschev <imz(a)altlinux.org> wrote: > Hi, > > I have some feedback on the API of the graphviz library's monadic API > (resulting form my explorations written down at > http://mathoverflow.net/a/203099/13991 ). > > Le jeudi 23 juin 2011 04:38:21 UTC+4, Ivan Lazar Miljenovic a écrit : >> >> On 23 June 2011 02:48, Stephen Tetley <stephen...@gmail.com> wrote: >> > Or Andy Gill's Dotgen - simple and stable: >> > >> > http://hackage.haskell.org/package/dotgen >> >> Within the next month, I should hopefully finally finish the new >> version of graphviz. Various improvements include: >> >> As such, I would greatly appreciate knowing what it is that makes you >> >> want to use a different library (admittedly the graphviz API isn't as >> stable as the others, but that's because I keep trying to improve it, >> and typically state in the Changelog exactly what has changed). >> >> > > ### graphviz Haskell library and other ones > > An alternative to "graphviz" Haskell package mentioned in > [haskell-cafe](https://groups.google.com/d/msg/haskell-cafe/ZfZaw2E9a18/xZ0O… > is [dotgen](http://hackage.haskell.org/package/dotgen). > > In [a > follow-up](https://groups.google.com/d/msg/haskell-cafe/ZfZaw2E9a18/9P-dazc… > to the post mentioning `dotgen`, the author of graphviz gives some > comparison between them (and other similar Haskell libs). I assume his > "plans" (about a monadic interface) have been implemented already: Yup: http://hackage.haskell.org/package/graphviz-2999.17.0.2/docs/Data-GraphViz-… > >> Within the next month, I should hopefully finally finish the new >> version of graphviz. Various improvements include: >> >> ... >> >> * A Dot graph representation based loosely upon **dotgen**'s monadic >> interface (with Andy's blessing) but with the various Attributes being >> used rather than (String, String). I think I'm going to be able to >> make it such that you can define a graph using the monadic interface >> that will almost look identical to actual Dot code. >> >> ... >> >> I would like to stress to people considering using other bindings to >> Graphviz/Dot (such as **dotgen**, language-dot, or their own >> cobbled-together interface): be very careful about quoting, etc. I >> have spent a _lot_ of time checking how to properly escape different >> values and ensuring correctness under the hood (i.e. there is no need >> to pre-escape your Text/String values; graphviz will do that for you >> when generating the actual Dot code). This, after all, is the point >> of having existing libraries rather than rolling your own each time. > > Both points are related. (So, graphviz's monadic iterface is a safer > improvement upon dotgen's one.) > > ### Considering dotgen vs graphviz closer > > But looking into the examples, I see that `dotgen` can use "Haskell > ids" to identify created nodes, whereas in graphviz's monad (see the > example above) one must supply extra strings as the unique ids (by > which we refer to the nodes). I used Strings as an example, as I was directly converting an existing piece of Dot code; the original can be found here: http://hackage.haskell.org/package/graphviz-2999.17.0.2/docs/Data-GraphViz-… But, you can use any type you like for the node identifiers, as long as you make them an instance of the PrintDot class. That's where the `n` in the `Dot n` type comes in. > > I like the first approach more ("Haskell ids"). I admittedly don't have any ability in graphviz to create new identifiers for you. I could (just add a StateT to the internal monadic stack which keeps track of the next unused node identifier) but I think that would _reduce_ the flexibility of being able to use your own type (it would either only work for `Dot Int`, or even if you could apply a mapping function to use something like `GraphID`, but that has a problem if you have a `Double` with the same value - and hence same textual representation - as your Int). The way I see it, graphviz is usually used for converting existing Haskell values into Dot code and then processing with dot, neato, etc. the Monadic interface exists so that you can still use the library for static pre-specified graphs (I wrote the module for a specific use case, but in practice found it not as useful as I thought it would be as I typically don't have a need for static graphs in my Haskell code). > > Cf. dotgen (from > <https://github.com/ku-fpg/dotgen/blob/master/test/DotTest.hs>): > > module Main (main) where > import Text.Dot > -- data Animation = Start > src, box, diamond :: String -> Dot NodeId > src label = node $ [ ("shape","none"),("label",label) ] > box label = node $ [ ("shape","box"),("style","rounded"),("label",label) > ] > diamond label = node $ > [("shape","diamond"),("label",label),("fontsize","10")] > main :: IO () > main = putStrLn $ showDot $ do > attribute ("size","40,15") > attribute ("rankdir","LR") > refSpec <- src "S" > tarSpec <- src "T" > same [refSpec,tarSpec] > c1 <- box "S" > c2 <- box "C" > c3 <- box "F" > same [c1,c2,c3] > refSpec .->. c1 > tarSpec .->. c2 > tarSpec .->. c3 > m1 <- box "x" > m2 <- box "y" > ntm <- box "z" > same [m1,m2,ntm] > c1 .->. m1 > c2 .->. m2 > xilinxSynthesis <- box "x" > c3 .->. xilinxSynthesis > gns <- box "G" > xilinxSynthesis .->. gns > gns .->. ntm > ecs <- sequence > [ diamond "E" > , diamond "E" > , diamond "Eq" > ] > same ecs > m1 .->. (ecs !! 0) > m1 .->. (ecs !! 1) > m2 .->. (ecs !! 0) > m2 .->. (ecs !! 2) > ntm .->. (ecs !! 1) > ntm .->. (ecs !! 2) > _ <- sequence [ do evidence <- src "EE" > n .->. evidence > | n <- ecs > ] > edge refSpec tarSpec > [("label","Engineering\nEffort"),("style","dotted")] > () <- scope $ do v1 <- box "Hello" > v2 <- box "World" > v1 .->. v2 > (x,()) <- cluster $ > do v1 <- box "Hello" > v2 <- box "World" > v1 .->. v2 > -- x .->. m2 > -- for hpc > () <- same [x,x] > v <- box "XYZ" > v .->. v > () <- attribute ("rankdir","LR") > let n1 = userNodeId 1 > let n2 = userNodeId (-1) > () <- n1 `userNode` [ ("shape","box")] > n1 .->. n2 > _ <- box "XYZ" > _ <- box "(\n\\n)\"(/\\)" > netlistGraph (\ a -> [("label","X" ++ show a)]) > (\ a -> [succ a `mod` 10,pred a `mod` 10]) > [ (n,n) | n <- [0..9] :: [Int] ] > return () > My preference - and hence overall design with graphviz - is that you would generate the graph first, and _then_ convert it to a Dot representation en masse. > > Cf. graphviz with string ids: > > A short example of the monadic notation from [the > documentation](http://hackage.haskell.org/package/graphviz-2999.16.0.0/docs…: That version is a tad out of date, but shouldn't affect this. > > digraph (Str "G") $ do > > cluster (Int 0) $ do > graphAttrs [style filled, color LightGray] > nodeAttrs [style filled, color White] > "a0" --> "a1" > "a1" --> "a2" > "a2" --> "a3" > graphAttrs [textLabel "process #1"] > > cluster (Int 1) $ do > nodeAttrs [style filled] > "b0" --> "b1" > "b1" --> "b2" > "b2" --> "b3" > graphAttrs [textLabel "process #2", color Blue] > > "start" --> "a0" > "start" --> "b0" > "a1" --> "b3" > "b2" --> "a3" > "a3" --> "end" > "b3" --> "end" > > node "start" [shape MDiamond] > node "end" [shape MSquare] > > Thanks for the packages, and best wishes, > Ivan Z. -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com http://IvanMiljenovic.wordpress.com

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Re: [Haskell-cafe] Scala at position 25 of the Tiobe index, Haskell dropped
by Gregory Guthrie 17 Apr '15

17 Apr '15

I find that Haskell has a very different learning curve from other languages that I use/know/have-tried, in that the basic language itself is very simple and easy to learn and appreciate. However once one starts using a lot of monads and applicatives and other libraries, it can begin to look more like APL. >>> parser >>= >>> ( \s -> return ( pl' { P.payloadData = setField pld (Just s) } } ) ) Certainly one can learn to parse and read this, but with all of the new operators and thus syntax not familiar to standard IP language users. (Not a complaint, just an observation from teaching this to students new to FP.) And in my experience the cabal problems are the "fatal-flaw"; it is not infrequent that I have had to delete all libraries and start over, and I have only very simple usage. I would not want to have a business project that depended on this, as often I have not found a good solution where I could install all the packages I wanted. (Perhaps I just need to learn more about sandboxing techniques.) I am not a fan of the Scala syntax, but it does seem to be an easier transition because it look-and-feel's more like the typical IPs. ------------------------------------------- > -----Original Message----- ...

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