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Email spam from my account on May 26, 2011
by Gregory Propf 27 May '11

27 May '11

I just discovered that some evil spammer has somehow gotten my contacts list and used it to send out a bunch of spam. This is just to notify you that if you get an email from me on May 26, 2011 (other than this one or one like it - the problem was more extensive than I first thought) it wasn't from me. Please don't add me to your spam filters. I've changed my password and hopefully that's the end of it. At this point I don't know how they did it though. - Greg

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(no subject)
by Gregory Propf 27 May '11

27 May '11

As you my friend I invite you to visit my own site first!. http://prospero.ch/friends_links.php?uGIS=45ru4

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Policy for taking over a package on Hackage
by Ivan Lazar Miljenovic 26 May '11

26 May '11

With my wl-pprint-text package, Jason Dagit suggested to me on #haskell that it would make sense to make such a pretty-printer be class-based so that the same API could be used for String, ByteString, Text, etc. I was thinking of doing so, and in such a case it would probably make the most amount of sense to actually then migrate the package back to the wl-pprint package instead of defining yet another package (and corresponding namespace), especially as I recalled from when I first started hacking on wl-pprint-text at the beginning of the year that the last (and only) upload had been in 2007 by Stefan O'Rear. As such, I was going to email Stefan and asked if he minded if I took over maintaining wl-pprint. However, when I went to the package page to get his email address, I saw that Otakar Smrz had released a new version about a month ago, and that the only change in the package that I could find was that OverlappingInstances was added to the .cabal file (which I thought wouldn't make a difference anyway). Now, for all I know, Otakar had already asked Stefan for permission to take over the package (I've CC'd both of them just in case). But even if he didn't, we don't officially have any policies set in place - especially ones that are enforced by requiring registering a package and specifying a maintainer - to indicate that such a thing shouldn't be done. Furthermore, if packages aren't announced then there's no way for people to know that there _is_ a new maintainer. This situation also arose last year [1], and was resolved by someone volunteering to take over a package. However, no formal policy was set in place (despite one being proposed). As such, I'd like to propose the following policy based upon the one Ben Millwood proposed last time on how to take over maintainership of a package that hasn't been updated for a while: 1. Email the current listed maintainer and wait a specified period of time (e.g. 2 weeks). 2. Email haskell-cafe, explicitly CC'ing maintainers of reverse dependencies (at least those that are themselves still active) and request permission to take over. This way, people who know the maintainer might point out that they are indeed still around, etc. 3. If no-one objects within another two weeks, announce that you have taken over maintainership with a new email (in case people are ignoring the previous thread). 4. Upload a point release of the previous package (assuming it follows the PVP) with yourself as the new maintainer (just to get it out there). Alternatively, if you already have a new version ready to go then upload that. Of course, having a policy like this is useless if there is no way to enforce it. Is it possible at the very least to have Hackage note when a new version of a package is uploaded with a new maintainer and require it to be approved by someone before it iis officially available? I think this would be the bare minimum (as opposed to requiring explicit logins on a per-package basis or some kind of signing) required for this kind of scheme to be effective. [1]: http://www.haskell.org/pipermail/haskell-cafe/2010-August/081353.html and http://www.haskell.org/pipermail/haskell-cafe/2010-August/082319.html -- Ivan Lazar Miljenovic Ivan.Miljenovic(a)gmail.com IvanMiljenovic.wordpress.com

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Function application layout
by Jonas Almström Duregård 26 May '11

26 May '11

Hi, Would it be possible to allow this in Haskell (where <applied to> is some new operator or keyword): f <applied to> {x a;y b;z c} As an equivalent to: f (x a) (y b) (z c) Of course my intention is that the new keyword should initiate layout syntax so we can write this: f <applied to> x a y b z c In addition to the case where you have a big function application, this is useful for defining trees: Branch <applied to> Branch <applied to> Leaf Leaf Leaf Has something like this been suggested before? Are there any disadvantages other than a new keyword and some potential confusion for readers? Any suggestions for a good keyword? I suppose some variant of $ makes sense, a textual keyword like "with" would be nice but probably break a lot of code. Regards, Jonas

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Haskell Weekly News: Issue 183
by Daniel Santa Cruz 26 May '11

26 May '11

Welcome to issue 180 of the HWN, a newsletter covering developments in the Haskell community. This release covers the week of May 15 to 21, 2011. Announcements Janis Veigtlander announced that the 20th edition of the Haskell Communities and Activities reports is hot off the press! http://goo.gl/GRi7V Simon Marlow announced that he has put together a tutorial on Parallel and Concurrent programming in Haskell. http://goo.gl/LPst8 Quotes of the Week * Sergey Mironov:I looked further and found that 'Oleg already did it'. * monochrom: just say "yes" Top Reddit Stories * Wolfgang - A Wolfram Alpha clone in Haskell (under heavy load?) Domain: jabberwock.xs4all.nl, Score: 75, Comments: 10 On Reddit: http://goo.gl/okNC7 Original: http://goo.gl/7pSXA * Numeric Haskell: a tutorial about the multi-dimensional, parallel arrays package, Repa Domain: haskell.org, Score: 54, Comments: 7 On Reddit: http://goo.gl/ZRSn3 Original: http://goo.gl/InWB9 * Space leak zoo: a catalog of common space leaks in Haskell programs Domain: blog.ezyang.com, Score: 41, Comments: 7 On Reddit: http://goo.gl/npVLv Original: http://goo.gl/aMbo5 * Exercises in Optimization: A (soon to be) three-part series detailing an adventure in optimizing Haskell code. Domain: csks.wordpress.com, Score: 34, Comments: 0 On Reddit: http://goo.gl/cjWBX Original: http://goo.gl/wPqbl * Tutorial: Parallel and Concurrent Programming in Haskell :: PDF Domain: community.haskell.org, Score: 33, Comments: 7 On Reddit: http://goo.gl/CB1wt Original: http://goo.gl/yzTOU * Anatomy of a thunk leak: How to debug Haskell’s most famous space leak Domain: blog.ezyang.com, Score: 32, Comments: 3 On Reddit: http://goo.gl/f18jX Original: http://goo.gl/PiQ98 * Preview release of diagrams EDSL for declarative drawing Domain: haskell.org, Score: 31, Comments: 9 On Reddit: http://goo.gl/6sykO Original: http://goo.gl/uhbV1 * I/O is not a monad Domain: r6.ca, Score: 31, Comments: 23 On Reddit: http://goo.gl/zAra5 Original: http://goo.gl/mn49r * Eliza in 70 lines of Haskell Domain: github.com, Score: 28, Comments: 7 On Reddit: http://goo.gl/hjgNf Original: http://goo.gl/S7t9m * The "Whole Program" Fallacy Domain: lukepalmer.wordpress.com, Score: 26, Comments: 10 On Reddit: http://goo.gl/Efja3 Original: http://goo.gl/vzXVK Top StackOverflow Questions * What Haskell representation is recommended for 2D, unboxed pixel arrays with millions of pixels? votes: 48, answers: 3 Read on SO: http://goo.gl/gVpwB * Good introductory text about GHC implementation? votes: 24, answers: 2 Read on SO: http://goo.gl/6MZoh * Questions on a Haskell -> C# conversion votes: 13, answers: 3 Read on SO: http://goo.gl/0t3Gu * Can't perform I/O in foldr? votes: 12, answers: 4 Read on SO: http://goo.gl/d9Jg0 * What does "this function will fuse" mean? votes: 11, answers: 3 Read on SO: http://goo.gl/tMdlR * Haskell function type question votes: 10, answers: 3 Read on SO: http://goo.gl/gyTns * Is this always true: fmap (foldr f z) . sequenceA = foldr (liftA2 f) (pure z) votes: 10, answers: 1 Read on SO: http://goo.gl/emKmg * Difference between hsc2hs and c2hs? votes: 8, answers: 2 Read on SO: http://goo.gl/1wnhC * Is it possible to create PHP extensions in Haskell? votes: 8, answers: 2 Read on SO: http://goo.gl/QwkpK * How can configuration tools like sdl-config be used with a cabalized project? votes: 8, answers: 2 Read on SO: http://goo.gl/vHCOu About the Haskell Weekly News To help create new editions of this newsletter, please send stories to dstcruz(a)gmail.com. Until next time, Daniel Santa Cruz

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[ANN] Released HSnippets, Emacs YASnippets for Haskell
by Christophe McKeon 26 May '11

26 May '11

Just released HSnippets, Emacs YASnippet snippets for Haskell https://github.com/polypus74/HSnippets cheers, _c

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lambdabot hoogle
by Jacek Generowicz 25 May '11

25 May '11

I have recenly installed lambdabot. Its response to *each* *and* *every* hoogle command is *always* A Hoogle error occurred. I'm hoping that someone on Cafe might be able to offer a more helpful diagnosis than this ... erm ... terse ... error message.

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lambdabot check
by Jacek Generowicz 25 May '11

25 May '11

I've installed lambdabot, but check within it seems to be broken: the only answer it ever gives is "Terminated". For example: lambdabot> check True Terminated lambdabot> quickCheck works just fine in a GHCi session: Prelude> :m + Test.QuickCheck [...] Prelude> quickCheck True [...] +++ OK, passed 100 tests. (GHC 7.0.3 on Ubuntu Natty, everything freshly installed with cabal install as far as possible.) Any advice?

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Calling a C function that returns a struct by value
by Matthew Steele 25 May '11

25 May '11

From Haskell, I want to call a C function that returns a struct by value (rather than, say, returning a pointer). For example: typedef struct { double x; double y; } point_t; point_t polar(double theta); I can create a Haskell type Point and make it an instance of Storable easily enough: data Point = Point CDouble CDouble instance Storable Point where -- insert obvious code here And now I want to do something like this: foreign import ccall unsafe polar :: CDouble -> IO Point ...but that doesn't appear to be legal (at least in GHC 6.12). Is there any way to import this C function into Haskell _without_ having any additional wrapper C code? I mean, I suppose I could write something like: // C: void polar_wrapper(double theta, point_t* output) { *output = polar(theta); } -- Haskell: foreign import ccall unsafe polar_wrapper :: CDouble -> Ptr Point - > IO () polar :: CDouble -> IO Point polar theta = do -- insert obvious code here ...but that's a lot of extra boilerplate if I have many such functions to wrap, and it seems like GHC should be able to do that sort of thing for me. P-: Cheers, -Matt

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code review?
by Chris Bolton 25 May '11

25 May '11

Hey guys. Pretty new to haskell here. I've started off by writing a small command-line interface to plurk.. I was just wondering if anyone would be willing to give everything a look-over and lemme know what kinds of things I should be looking to improve upon, style-wise. Not sure I'm currently doing things in the 'haskell-way' so to speak . Thanks a bunch! https://github.com/saiko-chriskun/hermes (note: the JSON and Plurkell submodules are also mine.)

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