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sending email via gmail Re: [Haskell-cafe] Sending email from a Haskell program
by Thomas Hartman 05 Dec '08

05 Dec '08

I ran into this problem when I wanted to send email from a HAppS web app, routing it through gmail. There actually used to be an SMTP client in HAppS but it was dropped a while ago. The most common workaround appears to be, just use sendmail. But I couldn't figure out a way to get sendmail to interface with gmail. (I think there is a way, there are blogs on it, I just wasn't patient enough to follow the directions.) What I finally did is, I have successfully followed the instructions in http://www.ericstockwell.com/?p=3 to send myself email from the command line. So I will probably use HSH to run shell commands in my haskell web apps, to send email. This process only took a few minutes, and seemed easier than the postfix/sendmail solutions I came across. Of course, this only works in unixy environments. thomas. 2007/9/27 brad clawsie <clawsie(a)fastmail.fm>: >> jmuk's HaskellNet project from last year? >> >> http://darcs.haskell.org/SoC/haskellnet/HaskellNet/IMAP.hs > > sweet! was there any documentation created for this? examples? > anything? have people tried to make this work with ssl/tls libs? > > by the way there looks like some other gems in the haskellnet > dir. what exactly was haskellnet - a project to code to the major > network protocols? are these libs stable? how does the HTTP lib stack > up against Network.HTTP? any info on this project would be > appreciated. > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe >

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deleting spam on the wiki
by Duncan Coutts 05 Dec '08

05 Dec '08

Who is able to delete wiki spam? http://haskell.org/haskellwiki/?title=Special:Contributions&target=Tomso123 All the pages created by this user appear to be spam (check the google translation) so the account should probably be deleted too. As I understand it, any registered user can revert changes to a page: http://www.haskell.org/haskellwiki/Help:Editing However if a registered user creates new spam pages then other ordinary registered users cannot revert that change. Is there some way of reporting spam pages to the appropriate people that I missed? Duncan

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instance Applicative f => Applicative (StateT s f)
by Martijn van Steenbergen 05 Dec '08

05 Dec '08

Hello all, How do I implement the following? instance Applicative f => Applicative (StateT s f) The implementation of pure is trivial, but I can't figure out an implementation for <*>. Is it possible at all, or do I need to require f to be a monad? Thanks in advance, Martijn.

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Quickcheck in industry - own experience.
by Gianfranco Alongi 05 Dec '08

05 Dec '08

http://writert.blogspot.com/2008/12/quickchecking-code-i-c.html /Gf

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propogation of Error
by brad clawsie 05 Dec '08

05 Dec '08

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 hi. i have a partial library for parsing ogg files here: http://hpaste.org/12705 i have a question about an aspect of the code. in the function checkHeader there are a sequence of functions to check various elements in the header of a ogg file. if i test this function against a file that *isn't* an ogg file, i.e. badFile = "/home/user/.bashrc" :: String main = parseOgg badFile >>= (\x -> print x) i would expect to get back the Error from the *first* function in the sequence of functions in checkHeader (oggHeaderError from the oggHeader function). but instead i always see the Error from the *last* function in the sequence, OggPacketFlagError from the OggPacketFlag function. why is this? is there any way i can get the desired behavior...i.e. see the Error from the first function in the sequence that fails? thanks brad -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) iEYEARECAAYFAkk4tQYACgkQxRg3RkRK91PD9gCePloWFIvE9WjcfApxR2RmnHQ0 pUgAn0WAzRQR/y2yE8yeYP1s7eKHyKDh =EcOM -----END PGP SIGNATURE-----

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FunDeps vs. Associated Types
by Sebastian Fischer 05 Dec '08

05 Dec '08

Dear Haskellers, I have a question regarding the correspondence between functional dependencies and associated types. > {-# LANGUAGE TypeFamilies, > FlexibleInstances, > MultiParamTypeClasses, > FunctionalDependencies > #-} With associated types, we can define a (useless[^1]) type class > class Useless a > where > type T a > useless :: a -> T a and instances > instance Useless () > where > type T () = () > useless = id > > instance Useless a => Useless (() -> a) > where > type T (() -> a) = T a > useless f = useless (f ()) Now we can compute `()` in many different ways: useless () useless (\()->()) ... I thought I could express the same with a multi-parameter type class and a functional dependency: > class UselessFD a b | a -> b > where > uselessFD :: a -> b But the corresponding instances > instance UselessFD () () > where > uselessFD = id > > instance UselessFD a b => UselessFD (() -> a) b > where > uselessFD f = uselessFD (f ()) are not accepted (at least by ghc-6.10.1) without allowing undecidable instances: useless.lhs:50:2: Illegal instance declaration for `UselessFD (() -> a) b' (the Coverage Condition fails for one of the functional dependencies; Use -XUndecidableInstances to permit this) In the instance declaration for `UselessFD (() -> a) b' Is there a simple explanation for this? Cheers, Sebastian [^1]: Originally, I was implementing hidden generation of unique identifiers. So instead of `useless :: (() -> () -> ... -> ()) -> ()` I got something like `withUnique :: (ID -> ... -> ID -> a) -> a`.

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two type-level programming questions
by Nicolas Frisby 05 Dec '08

05 Dec '08

1) Type families, associated types, synonyms... can anything replace the use of TypeCast for explicit instance selection? Section 2, bullet 4 of http://www.haskell.org/haskellwiki/GHC/AdvancedOverlap indicates a negative response. Any other ideas? 2) Any progress/options for kind polymorphism in instances? Thanks for your time.

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manipulating predicate formulae
by Ganesh Sittampalam 05 Dec '08

05 Dec '08

Hi, Are there any Haskell libraries around for manipulating predicate formulae? I had a look on hackage but couldn't spot anything. I am generating complex expressions that I'd like some programmatic help in simplifying. Cheers, Ganesh

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Hat cannot use with ghc 6.10?
by Magicloud 05 Dec '08

05 Dec '08

Hi, I want to do some tracing, and I thought hat could help. Well hmake and hat both could not been made with ghc 6.10....

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Finall Call For Papers (DSL WC)
by Emir Pasalic 05 Dec '08

05 Dec '08

*** IFIP Working Conference on Domain Specific Languages (DSL WC) *** July 15-17, 2009, Oxford http://www.hope.cs.rice.edu/twiki/bin/view/WG211/DSLWC * Call for Papers Domain-specific languages are emerging as a fundamental component of software engineering practice. DSLs are often introduced when new domains such as web-scripting or markup come into existence, but it is also common to see DSLs being introduced and adopted for traditional domains such as parsing and data description. Developing software using DSLs has many benefits. DSLs are often designed based on existing notations that are already in use by experts in a given domain. As such, successful DSLs often reduce or eliminate the effort needed to transform the concept or innovation produced by the domain expert into an executable artifact or even a deliverable software product. DSL implementations can capture and mechanize a significant portion of the repetitive and mechanical tasks that a domain expert traditionally needed to perform in order to produce an executable. DSLs can in many cases capture and make widely available special expertise that only top specialists in a given domain might have. By capturing expert knowledge and reducing repetitive tasks, DSLs often also lead to software that is significantly more portable, more reliable and more understandable than it would otherwise be. DSLs can be viewed as having a dual role to general-purpose languages: whereas general purpose languages try to do everything as well as possible, DSLs are designed to find a domain where they can solve some class of problems -- no matter how small -- in the best possible way. Widely known examples of DSLs include Matlab, Verilog, SQL, LINQ, JavaScript, PERL, HTML, Open GL, Tcl/Tk, Macromedia Director, Mathematica/Maple, AutoLisp/AutoCAD, XSLT, RPM, Make, lex/yacc, LaTeX, PostScript, Excel, among many others. But while these tools have been widely successful, they still fall short of realizing the full idea behind them. The goal of this conference is to explore the extent to which incorporating modern principles of language design and software engineering can benefit existing and future domain-specific languages. The ultimate goal of using DSLs is to improve programmer productivity and software quality. Often, this is achieved by reducing the cost of initial software development as well as maintenance costs. These improvements - programs being easier to write and maintain - materialize as a result of domain-specific guarantees, analyses, testing techniques, verification techniques, and optimizations. * Paper Criteria Papers are sought addressing the research problems, fundamental principles, and practical techniques of DSLs, including but not limited to: - Foundations, including semantics, formal methods, type theory, and complexity theory - Language design, ranging from concrete syntax to semantic and typing issues - Software engineering, including domain analysis, software design, and round-trip engineering - Software processes, including metrics for software and language evaluation - Implementation techniques, including parsing, compiling, and program generation - Program analysis and automated transformation - Reverse engineering, re-engineering, design discovery, automated refactoring - Hardware/software codesign - Programming environments, including visual languages, debuggers, and testing infrastructure - Teaching DSLs and the use of DSLs in teaching Case studies, including engineering, bioinformatics, hardware specification languages, parallel computing languages, real-time and embedded systems, and networked and distributed domains Papers will be judged on the depth of their insight and the extent to which they translate specific experience into general lessons for domain-specific language designers and implementers, and software engineers. Papers can range from the practical to the theoretical; where appropriate, they should refer to actual languages, tools, and techniques, provide pointers to full definitions and implementations, and include empirical data on results. * Important Dates - July 23rd, 2008: First Call for Papers - November 12th, 2008: Final Call for Papers - December 14th, 2008: Abstract submission due. - December 21st, 2008: Paper submission deadline. - February 23rd, 2009: Author notification of decisions - March 22nd, 2009: Camera ready manuscripts due * Instructions for Authors Proceedings will be published in the Springer LNCS series. Submissions and final manuscripts are to follow the LNCS stylesheet formatting guidelines, and are not to exceed 25 pages. Please submit your manuscripts online using the EasyChair conference management system. * Program Committee Jon Bentley, Avayalabs Martin Erwig, Oregon State University Jeff Gray, University of Alabama at Birmingham Robert Grimm, New York University Jim Grundy, Intel Strategic CAD Labs Tom Henzinger, EPFL Sam Kamin, UIUC Dick Kieburtz, Portland State University Ralf Lämmel, University of Koblenz Julia Lawall, University of Copenhagen Benjamin Pierce, University of Pennsylvania Vivek Sarkar, Rice University Jeremy Siek, University of Colorado at Boulder José Nuno Oliveira, University of Minho Doaitse Swierstra, Utrecht University Walid Taha (Chair), Rice University Eelco Visser, Delft University William Waite, University of Colorado at Boulder Stephanie Weirich, University of Pennsylvania * Organizers General Chair: Jeremy Gibbons, Oxford University Publicity Chair: Emir Pasalic, LogicBlox

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