January 2006 - Glasgow-haskell-users

RE: GHC-6.4.1 on FreeBSD-amd64 port progress
by Simon Marlow 30 May '06

30 May '06

On 25 October 2005 10:01, Wilhelm B. Kloke wrote: > Simon Marlow <simonmar(a)microsoft.com> schrieb: >> On 24 October 2005 19:04, Wilhelm B. Kloke wrote: >> >> Is it that it does not find the libraries, or does it find the >> libraries but still gets a bunch of undefined references? If the >> latter, then there could be an issue with the mangler. Try an 'nm' >> on libHSbase.a to see if the missing symbols are actually defined. > > Nm shows that the problem may come from splitting. The missing symbols > are marked as locals (small d); being in different .o modules they > are not resolved. Try with splitting off: set SplitObjs=NO in your mk/build.mk. Cheers, Simon

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RE: instance inference
by Simon Peyton-Jones 06 Feb '06

06 Feb '06

Interesting example. Yes, GHC builds recursive dictionaries these days. There's a bit of discussion in our SYB paper in ICFP'05. http://research.microsoft.com/%7Esimonpj/papers/hmap/ And Martin Sulzmann has a whole paper about this point. http://www.comp.nus.edu.sg/~sulzmann/ ("Co-induction...") Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Ross Paterson | Sent: 12 December 2005 10:46 | To: glasgow-haskell-users(a)haskell.org | Subject: instance inference | | I'm puzzled that the following is accepted. Is some sort of greatest | fixed point computation used for instances? | | {-# OPTIONS_GHC -fglasgow-exts #-} | module M where | | class C a b where c :: a -> b -> Bool | | instance C b b => C (Maybe a) b where c x y = c y y | | f :: Maybe a -> Bool | f x = c x x | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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RE: Linking with C++ produced by Visual Studio .NET on Windows XP?
by Simon Peyton-Jones 03 Feb '06

03 Feb '06

GHC now makes it easy for all users to contribute new documentation about GHC to help other users, by adding to the GHC documentation wiki. See the "Collaborative documentation" heading on http://haskell.org/haskellwiki/GHC:Documentation Linking to C++ would be an ideal topic. It's a regular question, and not one of our strengths at GHC HQ! Simon | -----Original Message----- | From: glasgow-haskell-users-bounces(a)haskell.org [mailto:glasgow-haskell-users- | bounces(a)haskell.org] On Behalf Of Cyril Schmidt | Sent: 23 January 2006 09:57 | To: glasgow-haskell-users(a)haskell.org | Subject: Re: Linking with C++ produced by Visual Studio .NET on Windows XP? | | I am far from being an expert, but I have seen no answer to your question | so far, so I'll tell how I'd do it (however ugly that might be). I don't | have a sample project, but it should be fairly easy to make it. | | 1. Make a DLL project in Visual Studio. VS will create a .vcproj and | .sln files for you. Add your C++ source files to this project. | | 2. Create a .def file for your DLL. It might look like | LIBRARY MyDLL | EXPORTS | function1 | function2 | | where function1 and function2 are the names of the C++ functions that | you want to invoke from Haskell (there can be more of them, of course), | MyDLL is the name of your DLL. | | 3. Create an import library that can be used by ghc: | dlltool -d MyDLL.def -l libMyDLL.a | | where MyDLL.def is the name of the .def file, libMyDLL.a is the import | library. | | 4. Link your Haskell project, adding the library: | ghc --make main.hs -optl-lMyDLL -optl-L. | (-optl switch passes its argument as an option to the linker). | | Hope this helps. | | Cheers, | | Cyril | | ___ | | >Hi - | >I'm wondering if anyone has a simple Visual Studio .NET C++ project that | >would demonstrate how to link C++ with Haskell (or vice versa). Ie a .sln, | >.vcproj, .cpp, and .h file containing one C++ function and a Haskell file | >main.hs that calls this function, so that if I click on the .sln file and | >hit F6 the VS project will build then on the command line if I type | >ghc --make main.hs the Haskell program will be built so that when I type | >"main" on the command line it will run and call the C++ function. | | >Sorry if this all sounds too basic but I don't know how to compile C++ from | >the command line at all or how to use make files, and I need to use the | >Visual Studio compiler because my own C++ code relies on Microsoft | >extensions...

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new i/o library
by Bulat Ziganshin 03 Feb '06

03 Feb '06

Hello Simon i'm now write some sort of new i/o library. one area where i currently lacks in comparision to the existing Handles implementation in GHC, is the asynchronous i/o operations. can you please briefly describe how this is done in GHC and partially - why the multiple buffers are used? i'm now use just one buffer, which can contain read or write data, but not both - this buffer is just flushed before switching "mode" of operations. am i lose something due to this simplified algorithm? moreover, i have an idea how to implement async i/o without complex burecreacy: use mmapped files, may be together with miltiple buffers. for example, we can allocate four 16kb buffers. when one buffer is filled with written data, the program unmaps it and switches to use the next buffer. i don't tested it, but OS can guess that unmapped buffer now should be asynchronously written to disk. the same for reading - when we completely read one buffer, we can unmap it, switch to the second buffer and map the third so that the OS can asynchronously fill the third buffer while we are reading second. should this work, at least on the main desktop OSes? at least, mmap/VirtualAlloc available afaik on the all ghc-supported platforms, so this should work anywhere. of course, this scheme omits async i/o on sockets in Windows -- Best regards, Bulat mailto:bulatz@HotPOP.com

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RE: Lexically scoped type variables
by Simon Peyton-Jones 02 Feb '06

02 Feb '06

It'll be the HEAD, when I commit; I'll send a message. SImon | -----Original Message----- | From: Christian Maeder [mailto:maeder@tzi.de] | Sent: 18 January 2006 16:18 | To: Simon Peyton-Jones | Cc: GHC Users Mailing List | Subject: Re: Lexically scoped type variables | | Simon Peyton-Jones wrote: | > I'm very interested to know whether you like it or hate it. | > In the latter case, I'd also like to know whether you also | > have programs that will be broken by the change. | | I don't use GADTs yet and I assume this change will not (seriously) | break our code, but let me/us know which compiler we should use for testing. | | Cheers Christian

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ghci from darcs HEAD buggy on MacOS X?
by Geoffrey Alan Washburn 27 Jan '06

27 Jan '06

I just installed the Darwin Ports ghc-devel package, which grabs the latest from the darcs repository. It seems to build fine, but when I run ghci it seems to run and work (as far as I've tested) just fine except that it beeps continuously. Any ideas?

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Full Release Notes for GHC 6.4.1?
by Rich Fought 26 Jan '06

26 Jan '06

Hello, I'm wondering if there exists a full description of bug fixes between GHC 6.4 and 6.4.1. The short one on the GHC web site only details new features. Specifically, I'm interested to know if there were any changes to the concurrency/threading portion of GHC? I'm encountering some nasty FFI/threading issues that are causing GHC 6.4 to crash. Thanks, Rich

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ghc and gcc-4
by Johannes Waldmann 24 Jan '06

24 Jan '06

are there known problems with ghc-6.4.* and gcc-4.*? It seems that -O2 does not work (on i386), as gcc says something like "Prologue junk". (Suse linux 10.0 comes with gcc-4.?`as default compiler). -- -- Johannes Waldmann -- Tel/Fax (0341) 3076 6479/80 -- ---- http://www.imn.htwk-leipzig.de/~waldmann/ -------

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Re: Linking with C++ produced by Visual Studio .NET on Windows XP?
by Cyril Schmidt 24 Jan '06

24 Jan '06

Brian Hulley wrote: > Thanks. The only problem is that dlltool doesn't work because I don't > have > cygwin installed. dlltool usually comes with the Windows distribution of GHC (at least GHC 6.4 and 6.4.1 have it; check gcc-lib directory). Cheers Cyril

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Re: Linking with C++ produced by Visual Studio .NET on Windows XP?
by Cyril Schmidt 23 Jan '06

23 Jan '06

I am far from being an expert, but I have seen no answer to your question so far, so I'll tell how I'd do it (however ugly that might be). I don't have a sample project, but it should be fairly easy to make it. 1. Make a DLL project in Visual Studio. VS will create a .vcproj and .sln files for you. Add your C++ source files to this project. 2. Create a .def file for your DLL. It might look like LIBRARY MyDLL EXPORTS function1 function2 where function1 and function2 are the names of the C++ functions that you want to invoke from Haskell (there can be more of them, of course), MyDLL is the name of your DLL. 3. Create an import library that can be used by ghc: dlltool -d MyDLL.def -l libMyDLL.a where MyDLL.def is the name of the .def file, libMyDLL.a is the import library. 4. Link your Haskell project, adding the library: ghc --make main.hs -optl-lMyDLL -optl-L. (-optl switch passes its argument as an option to the linker). Hope this helps. Cheers, Cyril ___ >Hi - >I'm wondering if anyone has a simple Visual Studio .NET C++ project that >would demonstrate how to link C++ with Haskell (or vice versa). Ie a .sln, >.vcproj, .cpp, and .h file containing one C++ function and a Haskell file >main.hs that calls this function, so that if I click on the .sln file and >hit F6 the VS project will build then on the command line if I type >ghc --make main.hs the Haskell program will be built so that when I type >"main" on the command line it will run and call the C++ function. >Sorry if this all sounds too basic but I don't know how to compile C++ from >the command line at all or how to use make files, and I need to use the >Visual Studio compiler because my own C++ code relies on Microsoft >extensions... >Thanks, >Brian.

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