- Haskell-Cafe - Haskell.org

yhc install fails
by Thomas Hartman 21 Nov '07

21 Nov '07

I'm having the devil of a time getting yhc to install. http://hpaste.org/4028 or for posterity root@none:~/yhc-install/yhc>scons ... blah blah blah... Compiling PreludeAux ( src/packages/yhc-base-1.0/PreludeAux.hs ) YHC_build(["src/packages/yhc-base-1.0/Foreign/Util.hbc"], ["src/packages/yhc-base-1.0/Foreign/Util.hs"]) inst/bin/yhc --core --cpp -c src/packages/yhc-base-1.0/Foreign/Util.hs Compiling Foreign.Util ( src/packages/yhc-base-1.0/Foreign/Util.hs ) YHC_build(["src/packages/yhc-base-1.0/Foreign/C/String.hbc"], ["src/packages/yhc-base-1.0/Foreign/C/String.hs"]) inst/bin/yhc --core --cpp -c src/packages/yhc-base-1.0/Foreign/C/String.hs Error: File not found, Foreign.Storable Reason: imported from Foreign.C.String Looked in: /root/yhc-install/yhc/src/packages/yhc-base-1.0/ /root/yhc-install/yhc/inst/lib/yhc/packages/yhc-base/1.0 scons: *** [src/packages/yhc-base-1.0/Foreign/C/String.hbc] Error 1 scons: building terminated because of errors. root@none:~/yhc-install/yhc>ghc --version The Glorious Glasgow Haskell Compilation System, version 6.8.1 advice? thomas.

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Re: wxHaskell / Proxima (was Tetris)
by Gerbo Engels 21 Nov '07

21 Nov '07

Peter Verswyvelen <bf3(a)telenet.be> wrote: > > Talking about wxHaskell, one of the applications shown on the website is > Proxima. I've been looking for something like that for a long time > (combined structural and freestyle editing). The screenshot > <http://wxhaskell.sourceforge.net/images/proxima-mac.png> seems to imply > that it supports Haskell. Anyone has experience with that? Recently, Proxima changed the GUI from wxHaskell to Gtk2Hs. And the screenshot is an instantiation of a Helium [1] editor (using Helium as the backend to show the type information and values in the editor), so no support for (full) Haskell yet. But I'm about to start my Master thesis project, which will (partially) be about creating a Proxima instance using GHC as the backend (and thus hopefully opening ways to implement a Haskell IDE). So maybe in some months Proxima does support full Haskell :) Gerbo [1] http://www.cs.uu.nl/helium/

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[Offtopic?] Cabal package license and copyright holder question
by Alfonso Acosta 21 Nov '07

21 Nov '07

Hi all, I don't know if this is the right place to ask but, since it's somehow Haskell-related I decided to use haskell-cafe. I'm cabalizing a library which, apart from my own code, has code taken from others. As it could be expected, each piece has its own copyright holder and (slightly) different license. The concrete holder and licenses are clearly annotated in every module. But, even with that, I'm not sure if I'm entitled to set an overall copyright holder and license for the whole cabal package. So, right now, I'm not sure about what license and holder filelds should I set in my .cabal file. Could anyone who had encounterd this problem before suggest a solution? Thanks, Fons

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More accessible papers
by Peter Verswyvelen 21 Nov '07

21 Nov '07

Most research papers have the same layout: two columns per A4 page. They mostly come as PDF or PS. Although this is standard, it is not really accessible for people with people with bad vision, who prefer larger fonts. When you print this, the fonts are rather small. For those people, a reflowable PDF would make much more sense, so they can choose how big the fonts are on screen & paper. Also, some of the new epaper devices, such as the Sony Reader or IRex, don't really support the format of these research papers (they become unreadable). Do any of you have ideas how to convert a two column per page PDF/PS to a single larger column per page, and maybe even reflowable PDF? Thanks, Peter

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State of the GHC-embedded Haddock (AKA Haddock 2.0)?
by Alfonso Acosta 21 Nov '07

21 Nov '07

Hi, Can someone shed some light on what's the state of GHC-Haddock? The thread [1] mentions a haddock.ghc repository which doesn't exist anymore. Are there any plans of releasing it anytime soon? I have a haddock-annotated library which makes massive use of TH, making Haddock 0.8 fail miserably Cheers, Fons .

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Re: GHC 6.8.1 and HDirect
by Olivier Boudry 21 Nov '07

21 Nov '07

On 11/21/07, Fernand <quarantedeux42(a)yahoo.fr> wrote: > > Hi dear fellow ghc users, > > I simply wanted to let people know that I apparently succeeded in > compiling a patched version of HDirect with GHC 6.8.1 (with typelibs > support). > At least, I could compile some of the examples and had very simple test > programs launch/connect to Word and Excel using automation. I lack time > to really clean up the library (I did not made any Cabal patch and > currently directly link with the « .a » and « .o » of the various > modules), but feel free to contact me if you need some help to use > hdirect with GHC 6.8.1. > > Sincerely yours, > > sL > > Hi Fernand, Congratulations! I once tried to compile HDirect with GHC 6.6.1 but finally stopped trying after having made a bunch of unsuccessful modifications. It's just too bad this library is no more maintained. Having a clean and maintained COM interface would be really valuable for Haskell. I would be interested in getting the patches for compiling HDirect with GHC 6.8.1. Cheers, Olivier.

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Re: [Haskell-cafe] More accessible papers
by Peter Verswyvelen 21 Nov '07

21 Nov '07

Christopher L Conway wrote: > style is attached (I'm sure many on the list already have it), in case > Peter is feeling brave. Note that the ACM has several different I'm feeling brave but tired ;-) Besides I'm spending all of my free time learning Haskell! :) I don't know tex at all, I just wanted to mention the unfortunate fact that people with bad eyes (or tired eyes, like mine) might have problems (well at least I have) reading this standard format. I did some Googling, and at first sight <http://www.ntg.nl/pipermail/ntg-pdftex/2006-May/002213.html> (but my sight is not that good ;-) creating a reflowable PDF from tex is not obvious. But it would already help a lot if instead of having two columns per page, we just had a single column, with less space between the margins, and using a >2x larger font. That can't be that hard I guess? Peter Well, I would Christopher L Conway wrote: > On Nov 19, 2007 2:57 PM, Neil Mitchell <ndmitchell(a)gmail.com> wrote: > >> Hi Peter, >> >> >>> Although this is standard, it is not really accessible for people with >>> people with bad vision, who prefer larger fonts. When you print this, the >>> fonts are rather small. For those people, a reflowable PDF would make much >>> more sense, so they can choose how big the fonts are on screen & paper. >>> >> It is the standard for ACM workshops and conferences, which includes >> ICFP and Haskell Workshop. All these PDF's are produced from a >> standard Latex class file. If you wrote to people expressing this, and >> did whatever magic is required to make the class file produce both the >> current format and a reflowable PDF, you might get somewhere. >> > > Neil, > > The person responsible for this at the ACM is Gerry Murray > (murray(a)hq.acm.org) He has been extremely responsive in the past when > I have had problems with the class file. The standard ACM conference > style is attached (I'm sure many on the list already have it), in case > Peter is feeling brave. Note that the ACM has several different > formats (e.g., journal vs. conference) and they would all need to be > updated. > > Chris >

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Re: [Haskell-cafe] More accessible papers
by Miguel Mitrofanov 21 Nov '07

21 Nov '07

> >Building a .tex file can be rather hard with packages and what-not, > >plus quite a few of us use lhst2tex as a preprocessor. It's not > >impossible, but its not trivial either, and I can't imagine that > >anyone would use a .tex over a PDF. > > > I would prefer the .tex version any day! Why not have both versions. Yeah, me too.

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Re: [Haskell-cafe] More accessible papers
by PR Stanley 21 Nov '07

21 Nov '07

>Hi Peter, > > > Yes, but why don't researchers just publish their TEX file? You can > > regard that as the "source code" for generating PDF/PS whatever no? > >Building a .tex file can be rather hard with packages and what-not, >plus quite a few of us use lhst2tex as a preprocessor. It's not >impossible, but its not trivial either, and I can't imagine that >anyone would use a .tex over a PDF. > >I would prefer the .tex version any day! Why not have both versions. Cheers, Paul

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Stream fusion for Hackage
by Don Stewart 21 Nov '07

21 Nov '07

Just a quick announce: the stream fusion library for lists, that Duncan Coutts, Roman Leshchinskiy and I worked on earlier this year is now available on Hackage as a standalone package: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/stream-fusion-0.… As described in the recent paper: "Stream Fusion: From Lists to Streams to Nothing at All" Duncan Coutts, Roman Leshchinskiy and Don Stewart. ICFP 2007 This is a drop-in replacement for Data.List. Haddocks here, http://code.haskell.org/~dons/doc/stream-fusion/ (but note the interface is exactly the same as the Data.List library) You might expect some small percent performance improvement for list heavy programs, using ghc 6.8 and this list library with -O2 (use -ddump-simpl-stats and look for: STREAM stream/unstream fusion messages, indicating your intermediate lists are getting removed. To get an idea of what is happening, consider this list program: foo :: Int -> Int foo n = sum (replicate n 1) Compiled with ghc-6.8.1 -O2 -ddump-simpl Normally, as sum is a left fold, an intermediate lazy list is allocated between the call to sum and replicate, as GHC currently does: foo :: Int# -> Int# foo n = Data.List.sum (case <=# n 0 of False -> go n True -> []) where go :: Int# -> [Int] -- intermediate list! go n = case <=# n 1 of False -> 1 : (go (n -# 1)) True -> [1] By using Data.List.Stream instead, you get a strict fused loop instead, with no intermediate structure allocated: loop_sum :: Int# -> Int# -> Int# loop_sum k n = case <=# n 0 of False -> loop_sum (k +# 1) (n -# 1) True -> k foo :: Int# -> Int# foo n = loop_sum 0 n This is a the halfway mark before porting other sequence types -- especially Data.ByteString -- over to the full stream fusion model (in particular, strict bytestrings will benefit a lot, due to the O(n) cost of intermediate bytestrings being removed). The stream fusion types and combinators are also available in stripped down form in the mlton sml compiler's extended prelude. Enjoy. -- Don

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