- Glasgow-haskell-users

Re: building ghc from source
by johago＠web.de 24 May '03

24 May '03

----- Original Message ----- From: Simon Peyton-Jones To: johago(a)web.de ; GHC bugs Sent: Monday, May 19, 2003 10:23 AM Subject: RE: building ghc from source [Redirecting this to GHC bugs] 9. Entered "./configure --host=i386-unknown-mingw32 --with-gcc=/cygdrive/c/MinGW/bin/gc c". No errors occurred. I believe your problem is here. You must not use Cygwin-style paths when specifying what GCC is. Instead use --with-gcc=c:/mingw/bin/gcc Can you let me know if that fixes it? (remove config.cache before reconfiguring) The online Building Guide is wrong on this point, but it's fixed in the repository. I'll try to get the fixed version online asap. Simon I tried to compile the current cvs sources (using the windows binary distribution of ghc-5.04.3), following your instructions. Giving a windows style path name for for the gcc executable seems to solve my (first) problem. According to Mike Thomas' and Derek Elkins' posts, I also enabled HAVE_O_BINARY in config.h. ./configure --build=i386-unknown-mingw32 --with-gcc=c:/MinGW/bin/gcc make --- snip --- [...] ../../glafp-utils/mkdependC/mkdependC -f .depend -I../../ghc/includes -s p -- -mno-cygwin -O -DTARGET_GHC -I../../ghc/includes -- GDITypes_stub_ffi.c Win3 2Bitmap_stub_ffi.c Win32Brush_stub_ffi.c Win32Clip_stub_ffi.c Win32Control_stub_ ffi.c Win32DLL_stub_ffi.c Win32Dialogue_stub_ffi.c Win32File_stub_ffi.c Win32Fon t_stub_ffi.c Win32Graphics2D_stub_ffi.c Win32HDC_stub_ffi.c Win32Icon_stub_ffi.c Win32Key_stub_ffi.c Win32MM_stub_ffi.c Win32Menu_stub_ffi.c Win32Misc_stub_ffi. c Win32NLS_stub_ffi.c Win32Palette_stub_ffi.c Win32Path_stub_ffi.c Win32Pen_stub _ffi.c Win32Process_stub_ffi.c Win32Region_stub_ffi.c Win32Registry_stub_ffi.c W in32Resource_stub_ffi.c Win32SystemInfo_stub_ffi.c Win32Types_stub_ffi.c Win32Wi nMessage_stub_ffi.c Win32Window_stub_ffi.c WndProc.c diatemp.c dumpBMP.c errors. c finalizers.c spawnProc.c ../../ghc/compiler/ghc-inplace -M -optdep-f -optdep.depend -optdep-s -optdepp -o suf o -H16m -O -cpp -fvia-C -optc-DTARGET_GHC -fglasgow-exts -package-name wi n32 -O -Rghc-timing -package lang GDITypes.hs StdDIS.hs Win32.hs Win32Bitmap.hs Win32Brush.hs Win32Clip.hs Win32Control.hs Win32DLL.hs Win32Dialogue.hs Win32Fil e.hs Win32Font.hs Win32Graphics2D.hs Win32HDC.hs Win32Icon.hs Win32Key.hs Win32M M.hs Win32Menu.hs Win32Misc.hs Win32NLS.hs Win32Palette.hs Win32Path.hs Win32Pen .hs Win32Process.hs Win32Region.hs Win32Registry.hs Win32Resource.hs Win32Spawn. hs Win32SystemInfo.hs Win32Types.hs Win32WinMessage.hs Win32Window.hs Win32Spawn.hs: can't locate import `GHC.Posix' make[2]: *** [depend] Error 1 make[1]: *** [boot] Error 1 make[1]: Leaving directory `/cygdrive/c/try6/fptools/hslibs' make: *** [build] Error 1 --- snap --- Unfortunately, module GHC.Posix doesn't exist. I read something about this module to be unavailable under mingw and that I first had to build a cygwin-ghc-inplace which supports posix and then compile mingw-ghc with it... Therefore, I try the following: ./configure --build=i686-pc-cygwin --host=i386-unknown-mingw32 omitting --with-gcc=c:/MinGW/bin/gcc Is this correct? Thanks again, Johannes johago(a)web.de

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instance MPlus IO?
by Hal Daume III 22 May '03

22 May '03

THe docs claim this instance exists, but it doesn't seem to. Moreoever, such an instance doesn't make sense to me. -- Hal Daume III | hdaume(a)isi.edu "Arrest this man, he talks in maths." | www.isi.edu/~hdaume

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RE: Converting things to and from binary
by Simon Marlow 21 May '03

21 May '03

> Several tests by SimonM and I have shown > that the bit style is about 20% slower than the byte style. Really? I seem to recall it was more like 250% :-) http://haskell.org/pipermail/libraries/2002-December/000742.html Cheers, Simon

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RE: Converting things to and from binary
by Simon Marlow 21 May '03

21 May '03

> (2) the York Binary library uses the IO monad, and presumably > various variables within a BinHandle, to keep track of state. > I think this is unnecessary, for example I don't think the > process of converting a value to a byte array should really > have to go through IO. We are supposed to be functional > programmers after all. When writing to a BinMem it would be possible to avoid the IO monad, and use something like the ST monad instead. However, I'm not sure it's worth making this generalisation, since it would necessarily complicate the library quite a bit. Do you have an application where being in the IO monad to do this stuff isn't possible, or is inconvenient? Cheers, Simon

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RE: Converting things to and from binary
by Simon Peyton-Jones 21 May '03

21 May '03

| There was a *long* discussion of this on the libraries list a few months | back. See | | http://haskell.org/pipermail/libraries/2002-November/000691.html | | and the discussion that followed. | | I think that we should | | (a) move this discussion to the libraries list and | (b) work from the point reached by those discussions It would be great if someone took ownership of the discussion and brought it to a conclusion, giving us all a library or libraries we could use. Volunteers, stand forth! Simon

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Re: Converting things to and from binary
by George Russell 21 May '03

21 May '03

Derek wrote (snipped) > What's wrong with NHC's Binary/BinArray library? There seems to be a > GHC port on the GreenCard page. The home page of the York Binary library seems to be http://www.cs.york.ac.uk/fp/nhc13/libs/Binary.html Malcolm will doubtless have something to say here. However I would say not that there's something "wrong" with the Binary/BinArray library, but that it seems to be addressed towards a different class of problems (specifically data-compression) to those I am interested in (blasting data rapidly in and out). The main differences are (1) the framework I proposed in the original message: http://haskell.org/pipermail/glasgow-haskell-users/2003-May/005166.html is byte-based, while the York Binary framework is bit-based. I would imagine that this means the York Binary framework would be very much less efficient at handling long sequences of bytes, since they will presumably have to be shifted before being written to the destination. (2) the York Binary library uses the IO monad, and presumably various variables within a BinHandle, to keep track of state. I think this is unnecessary, for example I don't think the process of converting a value to a byte array should really have to go through IO. We are supposed to be functional programmers after all. (3) the York binary library provides two things you can write bits to (a Handle, and a fixed area in memory) and a large set of operations (seek and co), but it would be difficult for a normal programmer to extend this. (For example, what about someone in GHC wanting to write to a Posix Fd?) On the other hand the framework I propose has only two basic operations for writing, and two for reading, which means it should be much easier to define alternative consumers and sources of binary data.

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Re: Glasgow-haskell-users digest, Vol 1 #816 - 1 msg
by George Russell 20 May '03

20 May '03

Hal Daume wrote a lot, including the following. > More seriously, I think the idea of going to and from lists of Word8 is > going to kill performance. Especially if you are going to write to a file > in the end. You're going to have to go: > > data structure -> [Word8] -> File > > and likely the middle won't be deforested by any compiler. Whether you > use functional arrays or lists is somewhat irrelevant -- functional arrays > are also exceedingly slow. I completely agree that going via lists of Word8's is unacceptable. My design does not require this. An array of Word8's can be written or read to a file in a single operation (not counting the length, which needs to be communicated some other way). When you need to write to an intermediate data structure, the most efficient implementation would probably be to write directly to an array, which you realloc as necessary. This could be wrapped up into a single pure operation of type :: HasBinaryWrite a => a -> Bytes (say). Of course you would need to use IO in the middle, since it happens that the current interfaces to blocks of reallocable bytes require IO, but I don't really see how that can be avoided, and the end-user doesn't have to see it.

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hsc2hs feature request
by Nicolas Oury 20 May '03

20 May '03

Hello, I don't know if it's the place for that but I've got a problem with hsc2hs. In the C output file, it produces a main function of type int main (void) I think, it would be better to produce int main (int argc, char *argv []) It could seem not important, but with some C libs (for example SDL on OS X) that overwrite the main function with their main function and redirect main to SDL_main, it creates problems. (I've got a conflicting type with declaration which disappears if I correct this). Best regards, Nicolas Oury

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Converting things to and from binary
by George Russell 20 May '03

20 May '03

Sorry, I know there was an ongoing discussion on this topic somewhere, but I can't find it, so I'll have to hope this list is the most appropriate. The general problem to solve is "How to we convert things to and from a binary format, so they can be efficiently written to and from disk". I have solved this (incompletely) twice myself, I expect Glasgow Haskell has solved it too, there really ought to be a standard solution. From the deficiencies of my incomplete solutions I conclude: (1) you don't want to force everything to go via single Haskell characters. This is horrendously inefficient when what you want is to blast in and out large quantities of binary data, and of course that's precisely where you probably want efficiency. (2) you don't want a binary converter only to be able to write to Handles. I've found myself that it's useful to be able to convert to (for example) vectors of bytes. Now my idea is that this be implemented using monads. For example, consider the problem of writing out data to be converted into binary. We might consider there to be two primitive operations, based on the types Byte (a single Byte) and Bytes (an array of bytes). (I'm not sure exactly what these types should actually be in GHC.) The consumer of binary data should provide a record like data WriteBinaryData m = WriteBinaryData { writeByte :: Byte -> m (), writeBytes :: Bytes -> m () } Then something which can be written out in a binary form would instance the class class HasBinaryWrite a where writeA :: Monad m => WriteBinaryData m -> a -> m () The advantage of this approach is that an instance of HasBinary can both be written to a file (m = IO) and to a byte vector. Also this should be fairly efficient I think, and it should be easy to build up more complex instances of binary. The converse functions would likewise use monads data ReadBinaryData m = ReadBinaryData { readByte :: m Byte, readBytes :: Int -> m Bytes } class HasBinaryRead a where readA :: Monad m => ReadBinaryData m -> m a and again we can instance this either for files or for byte vectors, and again building up more complex instances should be easy enough. I wonder if this is the best way of doing this kind of thing, and if so should it be implemented and put in the standard libraries? Also, what should Byte and Bytes actually be?

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please help me
by John Jonas Savimbi 20 May '03

20 May '03

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