- Glasgow-haskell-users

getContents
by George Russell 26 Oct '00

26 Oct '00

I don't really understand getContents. (Does anyone?) I have some code here (far too large to submit). If I do (on Linux, ghc4.08.1, both with and without optimisation) ------------------ contents <- hGetContents handle seq (last contents) (hClose handle) ------------------ the code works. However I looked at the manual and it seems that hClose should force the whole of contents to be read anyway. So I changed it to ------------------ contents <- hGetContents handle hClose handle ------------------ and then the code doesn't work. If these are meant to be the same, then we have a GHC bug. If not, could someone explain in words of one syllable why not? PS - if you want the source code you'll have to download and compile the whole of UniForM!!

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RE: Compiling mutually recursive modules involving instances
by Simon Peyton-Jones 26 Oct '00

26 Oct '00

The best thing to do is never to put an instance declaration in an hi-boot file. I don't think you ever really need to. In contrast, mutual recursion of type declarations is often unavoidable. The manual should really say this Simon | -----Original Message----- | From: José Romildo Malaquias [mailto:romildo@urano.iceb.ufop.br] | Sent: 24 October 2000 16:00 | To: glasgow-haskell-users(a)haskell.org | Subject: Compiling mutually recursive modules involving instances | | | Hello. | | I am having difficulties in compiling mutually recursive | modules involving classes and instances in GHC 4.08.1. | Basicaly I am not finding how to write a .hi-boot where | I want to put classes and instances. | | Consider a program with 3 modules: M1, M2 and Main. The | sources are attached to the message. What should go | into M2.hi-boot? Would anyone write M2.hi-boot for me | so that I can learn it. | | Thanks. | | Romildo | -- | Prof. José Romildo Malaquias <romildo(a)iceb.ufop.br> | Departamento de Computação | Universidade Federal de Ouro Preto | Brasil |

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Compiling mutually recursive modules involving instances
by José Romildo Malaquias 24 Oct '00

24 Oct '00

Hello. I am having difficulties in compiling mutually recursive modules involving classes and instances in GHC 4.08.1. Basicaly I am not finding how to write a .hi-boot where I want to put classes and instances. Consider a program with 3 modules: M1, M2 and Main. The sources are attached to the message. What should go into M2.hi-boot? Would anyone write M2.hi-boot for me so that I can learn it. Thanks. Romildo -- Prof. José Romildo Malaquias <romildo(a)iceb.ufop.br> Departamento de Computação Universidade Federal de Ouro Preto Brasil

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Overloaded function and implicit parameter passing
by José Romildo Malaquias 23 Oct '00

23 Oct '00

Hi. While experimenting with the implicit parameter extension to Haskell 98, implemented in GHC 4.08.1 and latest Hugs, I came accross a difference among those implementations regarding overloading functions with implicit parameters. As a test consider the program ------------------------- cut here module Main where class C a where f :: (?env :: Integer) => a -> Integer instance C Integer where f x = ?env + x main = putStrLn (show (f (45::Integer) with ?env = 100)) ------------------------- cut here Hugs accepts this program and outputs 145, as expected. But GHC 4.08.1 refuses to compile it, emitting the message $ ghc -fglasgow-exts Test1.hs -o test1 Test1.hs:7: Unbound implicit parameter `env_rJX :: Integer' arising from use of `env_rJX' at Test1.hs:7 In the first argument of `+', namely `env_rJX' In the right-hand side of an equation for `f': env_rJX + x Compilation had errors Would anybody comment on what is going on with GHC? I am willing to use implicit parameters in the software I am developing, but I have the need to overload functions with implicit parameters. While Hugs is good for development, its performance may rule it out when the final product is ready. So I will need a good Haskell compiler to compile my system. Any comments? Romildo -- Prof. José Romildo Malaquias <romildo(a)iceb.ufop.br> Departamento de Computação Universidade Federal de Ouro Preto Brasil

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RE: Interface Files _ HOWTO?
by Simon Peyton-Jones 23 Oct '00

23 Oct '00

Compile the module from bottom to top, with -c. Then link. THus ghc -c MyList.hs ghc -c ListFun.hs ...etc... ghc -c Main.hs ghc -o MyApp MyList.o ListFun.o ... Main.o Simon | -----Original Message----- | From: Ingo Sander [mailto:ingo@ele.kth.se] | Sent: 20 October 2000 17:09 | To: glasgow-haskell-users(a)haskell.org | Subject: Interface Files _ HOWTO? | | | After working a lot with Hugs I tried to compile my Haskell | code with GHC. | But it does not work, I am not able to figure out how to work with the | interface files (.hi). My program is build out of several | modules, like | this (much simpler, but facing the same problem...) | | File MyList.hs | ============== | | module MyList(MkList(Empty, (:-))) where | | infixr 5 :- | | data MkList a = Empty | | a :- (MkList a) deriving (Eq, Show) | | | File ListFun.hs | =============== | | module ListFun(mapL) where | | import MyList | | mapL f Empty = Empty | mapL f (x:-xs) = f x :- mapL f xs | | | | File ListLib | ============ | | module ListLib(module MyList, module ListFun) where | | import MyList | import ListFun | | | File Main.hs | ============ | | module Main(main) where | | import ListLib | | main = putStr (show (mapL (+1) (1:-2:-Empty))) | | | | As I said the code works with hugs, and I want to have the | hierarchy in | the library structure. | | So, how do I compile this in GHC? I hoped, that it would be enough to | compile all files with the -c option (generating .hi and .o files) and | then compiling Main.hs to get an executable program. Howeve, I get the | following: | | > ghc Main.hs | ghc: module version unchanged at 7 | Undefined first referenced | symbol in file | MyList_ZCzm_con_info Main.o | MyList_zdfShowMkList_closure Main.o | ListFun_mapL_closure Main.o | MyList_Empty_static_closure Main.o | ld: fatal: Symbol referencing errors. No output written to a.out | | So, what's wrong, and am I totally on the wrong track... (I | studied the | GHC User Guide, but could not find the answer to my problem). | | Thanks in advance! | | Ingo Sander | | | | _______________________________________________ | Glasgow-haskell-users mailing list | Glasgow-haskell-users(a)haskell.org | http://www.haskell.org/mailman/listinfo/glasgow-haskell-users |

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Interface Files _ HOWTO?
by Ingo Sander 20 Oct '00

20 Oct '00

After working a lot with Hugs I tried to compile my Haskell code with GHC. But it does not work, I am not able to figure out how to work with the interface files (.hi). My program is build out of several modules, like this (much simpler, but facing the same problem...) File MyList.hs ============== module MyList(MkList(Empty, (:-))) where infixr 5 :- data MkList a = Empty | a :- (MkList a) deriving (Eq, Show) File ListFun.hs =============== module ListFun(mapL) where import MyList mapL f Empty = Empty mapL f (x:-xs) = f x :- mapL f xs File ListLib ============ module ListLib(module MyList, module ListFun) where import MyList import ListFun File Main.hs ============ module Main(main) where import ListLib main = putStr (show (mapL (+1) (1:-2:-Empty))) As I said the code works with hugs, and I want to have the hierarchy in the library structure. So, how do I compile this in GHC? I hoped, that it would be enough to compile all files with the -c option (generating .hi and .o files) and then compiling Main.hs to get an executable program. Howeve, I get the following: > ghc Main.hs ghc: module version unchanged at 7 Undefined first referenced symbol in file MyList_ZCzm_con_info Main.o MyList_zdfShowMkList_closure Main.o ListFun_mapL_closure Main.o MyList_Empty_static_closure Main.o ld: fatal: Symbol referencing errors. No output written to a.out So, what's wrong, and am I totally on the wrong track... (I studied the GHC User Guide, but could not find the answer to my problem). Thanks in advance! Ingo Sander

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GHC RPMs for RedHat 7
by Reuben Thomas 19 Oct '00

19 Oct '00

There are now GHC RPMs for RedHat 7 available from the download page (http://www.haskell.org/ghc/download.html) Note that (as stated there) you need to install GMP 2 RPMs if you don't have them already (they're provided). The development version of GHC has now moved to GMP 3, so we'll have this wrinkle ironed out in the next release. -- http://sc3d.org/rrt/ | certain, a. insufficiently analysed

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RE: GHC RPMs for RedHat 7
by Simon Marlow 19 Oct '00

19 Oct '00

> Keith Wansbrough wrote: > > > > > On this subject, where am I to get the libgmp2.a required > by 4.08.1 > > > (on Linux anyway). I tried compiling the very latest > version of GMP > > > but it only produced a libgmp.a file. Is that the same? > > > > Same happened to me. ln -s libgmp.a libgmp2.a worked for > me. I satisfied myself I was doing the right thing by > noticing all the 2.x.x version numbers on the libgmp source > I'd compiled. > Yes, that's what I did. Probably everyone has . . . Sorry about that, my fault. I built the binary distribution from a build linked against libgmp2.a on our box here, and it isn't reasonable to expect everyone to have that library with the same name. In the future the binary distributions will come with a static libgmp, but the RPMs will still have a dependency on the right external gmp package. Cheers, Simon

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RE: Socket.hs problem under Windows 2000
by Sigbjorn Finne 18 Oct '00

18 Oct '00

You need to init WinSock first, i.e., main = withSocketsDo $ do {...} --sigbjorn Martijn [mailto:martijn@cs.uu.nl] writes: > > Hi, > > I'm trying to set up some socket connections with Haskell on > a Windows 2000 > platform, but I can't seem to get them working. > > My program is rather simple: > -- > import Socket > > main = do { socket <- listenOn (PortNumber 1234) > ; return () > } > -- > > I know this shouldn't do anything at all, but instead it > gives an error > message: > > Fail: does not exist > Action: getProtocolByName > Reason: no such protocol entry > > I get the same message for any socket operation I try to > perform. Also a > basic call like getHostName from module BSD does not work. > I've compiled > with ghc version 4.05 with option "-syslib misc" > > Should I compile differently, is this a problem with CygWin, or am I > overlooking something? > > TIA, > Martijn Schrage >

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Socket.hs problem under Windows 2000
by Martijn 18 Oct '00

18 Oct '00

Hi, I'm trying to set up some socket connections with Haskell on a Windows 2000 platform, but I can't seem to get them working. My program is rather simple: -- import Socket main = do { socket <- listenOn (PortNumber 1234) ; return () } -- I know this shouldn't do anything at all, but instead it gives an error message: Fail: does not exist Action: getProtocolByName Reason: no such protocol entry I get the same message for any socket operation I try to perform. Also a basic call like getHostName from module BSD does not work. I've compiled with ghc version 4.05 with option "-syslib misc" Should I compile differently, is this a problem with CygWin, or am I overlooking something? TIA, Martijn Schrage

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