- Glasgow-haskell-users

language shootout
by Brian Gregor 20 Feb '01

20 Feb '01

There's a page with microbenchmarks for a large array of languages, including Haskell: http://www.bagley.org/~doug/shootout/ and please note his disclaimer :-) : http://www.lib.uchicago.edu/keith/crisis/disclaimer.html Anyway, many of the categories are lacking a Haskell program. I've sent in 2. I thought that this could also serve as a nice little collection of examples for style and the use of some of the libraries in HSlibs for those of us (particularly me :) ) who are still learning the language. Any takers? -brian

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Exposing Haskell functions with String arguments in dll
by Janna Khegai 20 Feb '01

20 Feb '01

Hi, I want to expose the following Haskell function in dll to call it from Java application: trans: String -> IO String I read that I shoud use tools like GreenCard, HDirect or some marshalling libraries, but not sure, which way is better. If anyone has experience in this, I will be very grateful for an example, which shows the steps of bilding such dll. Thanks in advance, Janna Khegai.

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ANN: C->Haskell 0.8.1
by Manuel M. T. Chakravarty 19 Feb '01

19 Feb '01

I am pleased to announce the availability of version 0.8.1 of the interface generator C->Haskell. It works with the current stable release series 4.08.x of GHC as well as the current development series 4.11. For both versions of GHC, it supports the *same* FFI library that GHC natively only supports in the development version 4.11 and which constitutes the result of the work of the FFI Task Force over the last couple of months. The interface specification of the library is online available at http://www.cse.unsw.edu.au/~chak/haskell/c2hs/docu/c2hs-4.html For more information on C->Haskell and for downloading, see http://www.cse.unsw.edu.au/~chak/haskell/c2hs/ The main feature in this release is the new FFI library. It should allow users of the GHC stable series to use the new FFI library interface, which we hope to keep stable from now on. An update of the C->Haskell tool proper is being worked at. Happy Hacking, Manuel

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[Bug #133086] complete failure (fwd)
by Reuben Thomas 19 Feb '01

19 Feb '01

[This sort of thing is probably better on the list, because it doesn't really isolate a bug] > Date: Mon, 19 Feb 2001 07:25:29 -0800 > From: noreply(a)sourceforge.net > To: noreply(a)sourceforge.net, noreply(a)sourceforge.net, cvs-ghc(a)haskell.org > Subject: [Bug #133086] complete failure > Bug #133086, was updated on 2001-Feb-19 07:25 > Here is a current snapshot of the bug. > Details: I have tried to install ghc-4.08.2 under Windows NT > and (as usal with the last few releases) failed. Sorry to hear you've had difficulties with recent releases; for most people things seem to have improved. > I get an immediate warning that DEFAULT_TMPDIR is not set to anything > useful. Check you've got the most recent InstallShield (same date as the current one); there's a bug in previous versions. > Although files will compile they run without producing > any output (even Hello World). This is the mingwin problem. > By the way, > I note that mingw from Cygwin has no version dated > 20001111 but the only version before this January > is listed as 20001225 (yes really Christmas day). There is a 20001111, but since it's now the last version but one it's not available directly from the installer; you have to get it by hand. Sorry about that. It looks as though the latest version (from this year) has cured the problem, so you could try using that instead. As I write I'm building GHC 4.08.2 with the new mingwin package installed; if that works, I'll ship a new InstallShield shortly.

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RE: Haskell threads & pipes & UNIX processes
by Simon Marlow 15 Feb '01

15 Feb '01

[ moved to glasgow-haskell-users(a)haskell.org... ] > I need to compress the output of my Hakell program. To avoid > the creation > of huge files, I want to compress before writing by means of gzip or > bzip2. However, this seems to be quite involved. > > I decided to run the compressor with > > runProcess :: FilePath -- Command > -> [String] -- Arguments > -> Maybe [(String, String)] -- > Environment(Nothing -> Inherited) > -> Maybe FilePath -- Working > directory (Nothing -> inherited) > -> Maybe Handle -- stdin (Nothing > -> inherited) > -> Maybe Handle -- stdout (Nothing > -> inherited) > -> Maybe Handle -- stderr (Nothing > -> inherited) > -> IO () > > First I wanted to use Posix.createPipe to connect to the > compressor but > Posix.createPipe returns a Fd. So this does not fit. Aha, you want the (unadvertised) function PosixIO.fdToHandle :: Fd -> Handle > I ended up with using Posix.createNamedPipe. This creates a named pipe > that can be openend with IO.openFile (which again yields the > Handle needed > for runProcess). > > At this point, it turned out that the pipe has to be opened > for reading > before it can be opened for writing (ghc-4.08.1). This seems > to be a bug. > (In a shell, the order does not matter; the processes are suspended > as expected.) We've had some problems with named pipes - check the archives of glasgow-haskell-bugs. It seems certain operating systems disagree on the semantics of a non-blocking open of a named pipe. I don't recommend using named pipes if you want portable code. > Then, as expected, the problem occured that writing to the pipe and > compressing cannot be sequenced. If the producer is started first, the > producer blocks because there is no consumer. If the consumer > is started > first, the consumer blocks because there is no input. > > So I played around with threads. If both consumer and producer are > executed as threads, the program terminates immediately without any > output. There seems to be no need to start executing any of > the threads. In GHC, the main program terminates as soon as the main thread terminates. It doesn't wait for any child threads to terminate - if you want this behaviour, you can program it using MVars. We'll be happy to look at any of the other problems you mentioned: please some code demonstrating the problem to glasgow-haskell-bugs(a)haskell.org. Cheers, Simon

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RE: Confused about enabling parallel ghc
by Simon Marlow 15 Feb '01

15 Feb '01

> I installed ghc 4.08.2 binaries for sparc solaris (and those for intel > linux, too), then tried compiling a sample program (the fibonacci one > in the user guide) with ghc -parallel. The compiler complained: > > Could not find interface file for `Prelude' > in the directories ./*.hi > /u/trebla/lib/ghc-4.08.2/imports/lang/*.mp_hi > > /u/trebla/lib/ghc-4.08.2/imports/concurrent/*.mp_hi > /u/trebla/lib/ghc-4.08.2/imports/lang/*.mp_hi > > /u/trebla/lib/ghc-4.08.2/imports/concurrent/*.mp_hi > /u/trebla/lib/ghc-4.08.2/imports/std/*.mp_hi > > (and similarly for Parallel.) > > Does it mean I must build ghc myself from source? > > The user guide promises a lot of binary bundles such as par. Ever > since 4.0x, the ghc download page ceases to mention them. Where > are they? This just means that Parallel support isn't included in the binary bundle you have. In fact, parallel support is developed and distributed separately. Contact the GPH (Glasgow Parallel Haskell) folks for more information: http://www.cee.hw.ac.uk/~dsg/gph/ Cheers, Simon

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Confused about enabling parallel ghc
by Albert Lai 15 Feb '01

15 Feb '01

I installed ghc 4.08.2 binaries for sparc solaris (and those for intel linux, too), then tried compiling a sample program (the fibonacci one in the user guide) with ghc -parallel. The compiler complained: Could not find interface file for `Prelude' in the directories ./*.hi /u/trebla/lib/ghc-4.08.2/imports/lang/*.mp_hi /u/trebla/lib/ghc-4.08.2/imports/concurrent/*.mp_hi /u/trebla/lib/ghc-4.08.2/imports/lang/*.mp_hi /u/trebla/lib/ghc-4.08.2/imports/concurrent/*.mp_hi /u/trebla/lib/ghc-4.08.2/imports/std/*.mp_hi (and similarly for Parallel.) Does it mean I must build ghc myself from source? The user guide promises a lot of binary bundles such as par. Ever since 4.0x, the ghc download page ceases to mention them. Where are they?

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questions about the installation instructions for WinNT and ghc-4.08x
by andreas.marth＠daimlerchrysler.com 14 Feb '01

14 Feb '01

I have some question relating the intsallation of ghc-4.08x on a WinNT/cygwin system. In the installation instruction is under 2.2.2.1 paragraph "Here's how to install Cygwin" written: After installation, start up a Cygwin shell and issue the following command: mount -f c: / assuming you installed Cygwin at C:\cygwin; otherwise change the drive and directory as appropriate. (So it definitely says / is at c: not at c:\cygwin. But later, when setting the environment variables it seems like it is assumed that / is at c:\cygwin.) Is it right to mount / at c: or should it be c:\cygwin? In "2.2.2.2 Environment variables" is a table that says I should add C:\usr\bin to PATH. That directory does not exist. the directory C:\cygwin\usr\bin exists (assuming you installed Cygwin at C:\cygwin) but is empty. The C:\cygwin\bin directory seems to be the one meant. Should I add C:\cygwin\bin to PATH? The same table says that SHELL should be C:/usr/bin/bash. (Observe the '/' signs instead of '\'.) But bash is in C:\cygwin\bin (assuming you installed Cygwin at C:\cygwin). Should I set SHELL to C:\cygwin\bin\bash (does it matter if I write C:\cygwin\bin\bash or C:/cygwin/bin/bash?)? Okay that are my questions at the moment. Any help would be appreciated. PS:Is there still something else to observe than putting ghc into scope of PATH?

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Message: "DEFAULT_TMPDIR has not been set to anything useful!"
by Lescher Christian 13 Feb '01

13 Feb '01

After installing the newest version of GHC on WinNT/Cygwin, I get the message "DEFAULT_TMPDIR has not been set to anything useful!" when executing GHC (however, compilation is ok.) Setting DEFAULT_TMPDIR to "c:/tmp" didn't change anything. What may be wrong with my settings? Christian

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Re: mingw-20001111-1.tar.gz still needed for cygwin WinNT?
by Lescher Christian 13 Feb '01

13 Feb '01

I had the same problem, and I solved it by changing the setup.ini file after downloading & putting the old mingw archive in latest/mingw: @ mingw version: 20001111-1 install: latest/mingw/mingw-20001111-1.tar.gz 130113 source: latest/mingw/mingw-20001111-1-src.tar.gz 121498 Cheers, Christian

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