- Haskell-Cafe - Haskell.org

ANN: SVGFonts 0.1
by Tillmann Vogt 06 Apr '09

06 Apr '09

I hereby publish my first library in Haskell. SVGFonts 0.1 It parses the pretty unknown SVG Font format to produce outlines of characters. The big advantage of this format is that it is XML, which means easy parsing and manipulating. Because I haven't found any svg-files on the Internet the typical way is to convert a more popular format (i.e. .ttf) into SVG Font via fontforge. This library may be useful if you want to have a direct access to specific algorithms which is of course harder when using a binding (i.e. Jeff Heards FTGL binding). The speed is improvable (see TO DO list) and since since this is my first library there might some errors which I am not aware of (please tell me). I also wonder why the library doesn't appear under graphics on hackage, although there is Category: Graphics in my cabal file. Depending on which library I like more, I will maybe integrate SVGFonts into LambdaCube or Fieldtrip Cheers, Tillmann

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Re: [Haskell-cafe] Combining sequences
by michael rice 06 Apr '09

06 Apr '09

I downloaded it and it appears more complicated than just adding files to a directory. There's a setup and a build, and no assurances it will work with Hugs. I think I'll wait for more information. Michael --- On Mon, 4/6/09, Thomas Hartman <tphyahoo(a)gmail.com> wrote: From: Thomas Hartman <tphyahoo(a)gmail.com> Subject: Re: [Haskell-cafe] Combining sequences To: "michael rice" <nowgate(a)yahoo.com> Cc: "Henning Thielemann" <lemming(a)henning-thielemann.de>, haskell-cafe(a)haskell.org Date: Monday, April 6, 2009, 12:26 AM It's not in hugs, nor in ghc. It's just in hackage. However, by the looks of it, you should probably be able to use it in hugs. I didn't actually check this, but the cabal file didn't name any fancy extensions, so it looks pretty cross-compiler. You can just go to http://hackage.haskell.org/cgi-bin/hackage-scripts/package/utility-ht-0.0.4 wget http://hackage.haskell.org/packages/archive/utility-ht/0.0.4/utility-ht-0.0… untar and put them with the rest of the files your hugs compiler uses for package import. (I don't actually know how package installation works in hugs... isn't it just put the files into a dir?) thomas. 2009/4/5 michael rice <nowgate(a)yahoo.com>: > Thanks. It looks like mergeBy will do the job, but is it available in Hugs? > > Michael > > > --- On Sun, 4/5/09, Henning Thielemann <lemming(a)henning-thielemann.de> > wrote: > > From: Henning Thielemann <lemming(a)henning-thielemann.de> > Subject: Re: [Haskell-cafe] Combining sequences > To: "michael rice" <nowgate(a)yahoo.com> > Cc: haskell-cafe(a)haskell.org > Date: Sunday, April 5, 2009, 9:09 PM > > > On Sat, 4 Apr 2009, michael rice wrote: > >> Is there a simple way to combine two sequences that are in ascending order >> into a single >> sequence that's also in ascending order? An example would be the squares >> [1,4,9,16,25..] >> combined with the cubes [1,8,27,64,125..] to form [1,1,4,8,9,16,25,27..]. > > http://hackage.haskell.org/packages/archive/utility-ht/0.0.4/doc/html/Data-… > > > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe > >

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Unary Minus
by Paul Keir 06 Apr '09

06 Apr '09

If I use :info (-) I get information on the binary minus. Is unary minus also a function? Thanks, Paul

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Questions about slow GC with STArray
by FFT 06 Apr '09

06 Apr '09

I've been following with interest the recent discussions on reddit about the extremely slow hash tables in Haskell compared to F# and OCaml, and as I understood it, this performance problem is caused by GC not liking mutable arrays http://hackage.haskell.org/trac/ghc/ticket/650 It appears from the discussion there that this is more than a simple bug, but a fundamental difficulty (slow writes vs slow GC trade-off). What I'm wondering though is how can this be unique to GHC: all arrays in OCaml and probably F# are mutable (and usually unboxed). How is this problem addressed there? Why is this supposed to be specific to boxed arrays only: wouldn't GC have to scan the whole mutable array whether it's boxed or unboxed?

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EclipseFP proposal for Google Summer of Code
by Thomas ten Cate 06 Apr '09

06 Apr '09

To everyone involved in the Google Summer of Code program, I have submitted a GSoC proposal to work on EclipseFP, the Haskell plugin for Eclipse. The proposal is crossposted to both haskell.org and the Eclipse Foundation, each in their respective templates. This is also stated at the top of the proposal. I send this e-mail because of possible scheduling issues: I will be away starting on April 15. So, if you want to ask me things, have suggestions for improvement, or want to do an interview or something, this can only be done *before* that date. This is also stated in the proposal, but since I have no idea how the proposals are processed by the mentoring organizations, I figured that an explicit notification would be a good idea. For your convenience, here are links to the proposal. haskell.org version: http://socghop.appspot.com/student_proposal/show/google/gsoc2009/thomastc/t… and also on http://docs.google.com/Doc?id=dfmvb7sr_13fzdg5qhr Eclipse Foundation version: http://socghop.appspot.com/student_proposal/show/google/gsoc2009/thomastc/t… and also on http://docs.google.com/Doc?id=dfmvb7sr_15gb9258fg If my schedule causes any problems, please let me know. Also, comments on the proposal in general would be much appreciated. Thanks, Thomas P.S. I hope it's okay that I post this to the haskell-cafe list as well; since haskell.org has no GSoC-specific mailing list, it seems to be the most appropriate place that I could find.

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high probability of installation problems and quality of the glorious implementation
by FFT 06 Apr '09

06 Apr '09

I'm still learning Haskell and also evaluating whether I want to use the language in my work. It seems like a fascinating language so far (although I don't know if laziness will be a detriment later for me eventually), but I'm a bit worried about the overall quality of its GHC implementation. For example, I tried installing GHC-6.10.2 on my Ubuntu 8.04 machine (probably the most mainstream Linux these days). 1st attempt: binary => failed "the impossible happened, report bug" (I think it's already in bugzilla for an even earlier version) 2nd attempt: source and docs => followed README, but "make" failed while building docs 3rd attempt: source only, no docs => make install succeeded, but ghci now seems to have its "readline" screwed up (no editing, can't quit even with Ctrl-C or Ctrl-D), while Ubuntu-bundled 6.8.* ghci works fine in this regard. If these kinds of issues are common only during installation, I can live with that, but if GHC is flaky overall, having to deal with this may cancel out whatever productivity advantages Haskell provides. If the quality of the installation procedures is different from the compiler itself, can you explain why?

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minor typo in "The Haskell 98 Report"
by Benjamin L.Russell 06 Apr '09

06 Apr '09

Today, as I was reading through "The Haskell 98 Report" (see http://www.haskell.org/onlinereport/) I came across a minor typo, but it seems that the only way to fix such typos is to report them on one of the Haskell mailing lists; viz.: >The original committees ceased to exist when the original Haskell 98 Reports were published, so every change was instead proposed to the entire Haskell mailing list. Therefore, please allow me to report this typo, though minor, here, as follows: The Haskell 98 Report - Preface (see http://www.haskell.org/onlinereport/preface-jfp.html) under the heading "Haskell 98: language and libraries," fourth paragraph, second line: >If these program were to be portable, a set of libraries would have to be standardised too. should be as follows: >If these programs were to be portable, a set of libraries would have to be standardised too. (I.e., the word "program" should be plural.) Is this the proper place to report any forthcoming similar typos? -- Benjamin L. Russell -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^

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Re: [Haskell] [OT] Plural forms of the word "octopus" [Was: Re: Marketing Haskell]
by ajb＠spamcop.net 06 Apr '09

06 Apr '09

[Shifted to haskell-cafe.] G'day all. Quoting "Benjamin L.Russell" <DekuDekuplex(a)Yahoo.com>: > According to the Merriam-Webster Online Dictionary, it is "topoi" (see > http://www.merriam-webster.com/dictionary/topos) Topoi form a certain class of category. You can study topous, you can prove theorems about topois and you can discover properties of topon. (That last one is an omega, so it's pronounced more like "top-own".) > Where did you find "octoposi?" In my ancient copy of Liddell and Scott. Here's the online entry: http://tinyurl.com/ck8gst Cheers, Andrew Bromage

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Linking hmatrix without LAPACK
by Duane Johnson 06 Apr '09

06 Apr '09

I'm curious if there is a quick fix to this. I installed GLS and hmatrix, and it runs wonderfully together in ghci. When I run ghc -- make, however, I run into the following link dependency: Linking SilkwormGame ... Undefined symbols: "_dgemm_", referenced from: _multiplyR in libHShmatrix-0.5.0.1.a(lapack-aux.o) "_dgesv_", referenced from: _linearSolveR_l in libHShmatrix-0.5.0.1.a(lapack-aux.o) ... etc Is there a way to tell ghc to not link these? Or am I making a poor assumption that if my code runs in ghci, it does not need LAPACK? Thanks, Duane Johnson

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cabal build on mac os 10.5.6 , can't find gmp
by brian 06 Apr '09

06 Apr '09

Hi, Cabal won't build zlib because it can't find libgmp. It's there, in /sw/lib (fink installation). I've modified the bootstrap script and added -L/sw/lib to the ghc options. This is a mystery in itself because ghc is itself a fink package and should know where gmp is, so that's already a bad sign. I can get to the build step with the additional -L option but then ./ Setup fails again because it can't find gmp. Help .... ? Thanks, Brian

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