February 2003 - Glasgow-haskell-users

RE: GHCi-5.04.2: Windows Open with ... problem.
by Simon Marlow 24 Feb '03

24 Feb '03

> Will this release include the -odir fix (the one for > hiearchical names)? I'm afraid not. That part of the compiler has changed a lot relative to the 5.04.x branch, the fix is non-trivial, and I don't feel confident making that kind of change at this stage of the release cycle. "Better the devil you know". Using make instead of --make, and explicit -o options instead of -odir, should let you workaround the problem. Cheers, Simon

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RE: identifying a raise_closure from C
by Simon Marlow 24 Feb '03

24 Feb '03

> In C, I have an StgClosure pointer, pointing to a THUNK. > > I would like to know whether this particular THUNK is a raise_closure, > (as built by raisezh_fast() in rts/Exception.hc). > > Is there any identifying information I can use to tell > definitely whether > this THUNK is a raise_closure? Perhaps the stg_raise_info info table > has enough information? Since raise closures don't have their own closure types, the only way is to compare the closure's info pointer against stg_raise_info. This is fine, and we use the same technique in several other places in the RTS. Cheers, Simon

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identifying a raise_closure from C
by Bernard James POPE 24 Feb '03

24 Feb '03

Hi all, In C, I have an StgClosure pointer, pointing to a THUNK. I would like to know whether this particular THUNK is a raise_closure, (as built by raisezh_fast() in rts/Exception.hc). Is there any identifying information I can use to tell definitely whether this THUNK is a raise_closure? Perhaps the stg_raise_info info table has enough information? Thanks heaps, Bernie.

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RE: compiling ghci...
by Simon Peyton-Jones 21 Feb '03

21 Feb '03

You probably want the cvs-ghc mailing list, used by GHC developers, rather than ghc-users. Assuming you already have a stage-2 compiler built (in ghc/compiler/stage2/ghc-inplace), if you change the RTS you should be able to type 'make' in ghc/rts, and then run the stage-2 compiler without recompiling either the stage-1 or stage-2 compiler. Simon | -----Original Message----- | From: Andre Rauber Du Bois [mailto:dubois@macs.hw.ac.uk] | Sent: 21 February 2003 12:16 | To: glasgow-haskell-users(a)haskell.org | Subject: compiling ghci... | | | Hello! | | I am playing with ghci and also trying to modify things in its | Scheduler. As ghci is only generated if it is compiled using the same | version of the compiler that you are trying to generate, if I change the | Scheduler.c file, I always have to compile the whole thing twice. I | already tried only recompiling the RTS but it does not work. Is there a | short cut, or, what files I have to recompile if I am changing the rts and | want to see these changes in ghci? | Is this the right place to ask these questions? :-) | | Cheers, | Andre. | -- | --------------------------------- | André Rauber Du Bois | dubois at macs.hw.ac.uk | http://www.macs.hw.ac.uk/~dubois/ | | _______________________________________________ | 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: permissions on ghc Windows installer?
by C.Reinke 21 Feb '03

21 Feb '03

To what extent does the windows ghc install actually depend on being in a particular place or having registry entries? Here, we'd occasionally like to use ghc on public machines which don't have it installed, and on which we have no installation permissions. Those machines do have access to network drives, however, for which we do have write permissions (though we don't have much control over the drive letter these appear under). Initial experiments (renaming installation directory after install; running ghc from a remote copy of the installation directory on a network server) at least do not fail immediately, so that may be a route. Sigbjorn also mentioned a while ago that there's a command-line way to run windows installers, with additional options.. hth, Claus > Thanks, I'll keep it in mind should I decide to revisit this. My > experiences of getting per-user installs to work reliably with > MSIs haven't been too positive. > > --sigbjorn > > ----- Original Message ----- > From: "Malcolm Wallace" <Malcolm.Wallace(a)cs.york.ac.uk> > To: <glasgow-haskell-users(a)haskell.org> > Sent: Monday, February 17, 2003 10:24 > Subject: permissions on ghc Windows installer? > > > > I have been attempting to solve some outstanding problems with > > building hmake, nhc98, and hat, using ghc under Windows. I don't > > have a Windows machine of my own, but our Dept has some public-access > > Windows 2000 Pro machines I can use. However, when I try to use the > > ghc .msi automatic installer package, it reports that I do not have > > sufficient privileges to install ghc in my own temporary disk area. > > Apparently it needs administrator privileges, which I do not have > > (and will not be able to acquire). > > > > Are administrator privileges really required? I notice that the > > installer for Cygwin (i.e. not ghc) explicitly allows you to choose > > whether to install for all users or "just for me". Would it be > > difficult to allow the same choice in the ghc installer? > > > > Regards, > > Malcolm > > _______________________________________________ > Glasgow-haskell-users mailing list > Glasgow-haskell-users(a)haskell.org > http://www.haskell.org/mailman/listinfo/glasgow-haskell-users

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compiling ghci...
by Andre Rauber Du Bois 21 Feb '03

21 Feb '03

Hello! I am playing with ghci and also trying to modify things in its Scheduler. As ghci is only generated if it is compiled using the same version of the compiler that you are trying to generate, if I change the Scheduler.c file, I always have to compile the whole thing twice. I already tried only recompiling the RTS but it does not work. Is there a short cut, or, what files I have to recompile if I am changing the rts and want to see these changes in ghci? Is this the right place to ask these questions? :-) Cheers, Andre. -- --------------------------------- André Rauber Du Bois dubois at macs.hw.ac.uk http://www.macs.hw.ac.uk/~dubois/

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beginner question on module loading error
by Olympia S 21 Feb '03

21 Feb '03

With the last couple of modules I have been trying to load in GHCi, I get the message 'can't find file...' Before, I was able to load modules without a problem (on the same day), so does anybody know a solution to this? I had saved my modules exactly the same way as the others that loaded. (I have just started learning haskell). Thanks... _________________________________________________________________ Hotmail now available on Australian mobile phones. Go to http://ninemsn.com.au/mobilecentral/hotmail_mobile.asp

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Small JAPI binding for GHC in CVS
by Mike Thomas 19 Feb '03

19 Feb '03

Hi there. Under "fptools/libraries/Japi" (the GHC CVS repository) please find a preliminary binding to a subset of the Japi library: http://www.japi.de/ from which site you can obtain precompiled libraries and headers for different platforms. Japi is a simple C wrapper on Java which means that either "jre" or "java" needs to be in your path, but it avoids callbacks and uses the Haskell 98 FFI so I would expect it to be easy to port to "nhc98". You have to do an event loop in Haskell. The makefiles have been tested with MinGW32 GHC, but I expect you would need little effort under Linux, for example. Some examples are provided including a Fractal program, based on the C originals including the one below which will probably have mangled formatting courtesy of Outlook. Cheers Mike Thomas. --------------------------------------------------- module Main(main) where import Graphics.UI.Japi.Binding import Graphics.UI.Japi.Types import Graphics.UI.Japi.Constants import Control.Monad main = do j_setdebug 4 rv <- j_start when (0 == rv) (error "Could not start the JAPI server (jre or java)") frame <- j_frame "Frame demo" j_show (Object $ fromIntegral $ frame) icon <- j_loadimage "../c-examples/images/new.gif" when (0 == icon) (error "Could not find the icon file.") j_seticon frame icon waitForFrameAction frame return j_quit waitForFrameAction :: Frame -> IO () waitForFrameAction frame = do rv <- j_nextaction when (not (rv == (EventListener $ fromIntegral $ frame))) (waitForFrameAction frame) return ()

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concurrent assertions [was re: awaitEval etc]
by Colin Runciman 19 Feb '03

19 Feb '03

Dean Herrington has mailed me to point out that the metatype is unnecessary: class Assert a where assertW :: MVar a -> a -> a assertR :: MVar a -> a instance Assert a => Assert [a] where assertW mv [] = unsafePerformIO $ do putMVar mv []; return [] assertW mv (x:xs) = unsafePerformIO $ do mvx <- newEmptyMVar mvxs <- newEmptyMVar putMVar mv (assertR mvx : assertR mvxs) return (assertW mvx x : assertW mvxs xs) assertR mv = unsafePerformIO $ takeMVar mv When I picked up Claus Reinke's suggestion I divided the problem into (1) define the writer, and then *separately* (2) define the reader, which led me to define a type explicitly representing the interface between the two. But I missed the opportunity to apply a suitable deforestation tactic at the end, eliminating this intermediate structure by shifting reader applications into the writer. Beside the elimination of the metatype, an additional attraction of this latest solution is that a single definition of assertR suffices for all instances. (Even without automation, defining assertW instances should be light work given a few handy combinators.) Thank you Dean! Colin R

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FreeBSD + FIFO pipes
by George Russell 19 Feb '03

19 Feb '03

Yes I know it's a FAQ, but despite the information in the GHC FAQ I can't get my program to work. I'm trying to get HTk to work on FreeBSD (actually FreeBSD running inside a VMware virtual machine, but I don't think that should make any difference). How HTk works is it creates a couple of pipes (readIn,writeIn) <- Posix.createPipe (readOut,writeOut) <- Posix.createPipe It then forks off a process which first dup2's readIn onto its stdin and writeOut onto its stdout, and then runs the Tcl/Tk shell wish (which does graphics). The idea is that sending commands along writeIn will cause them to be executed by wish, and wish's output can be read from readOut. We do the reading/writing of readOut/writeIn using the Posix fdRead/fdWrite primitives. In addition, before every call to fdRead we do a Posix.threadWaitRead on it, to make sure there is actually input there. All this works fine on Linux and Solaris by the way. (On Windows we use a completely different mechanism.) The problem I am getting with FreeBSD is that fdRead sometimes reports EOF, even though threadWaitRead has just reported the presence of data. (And no, I don't think we have a race condition here, the relevant bit of code is in an exclusive lock.) If I tell it to ignore the EOF and try to read again and again it just throws it into an endless loop, seemingly. The GHC FAQ says: > A workaround > for all systems is to open the FIFO for writing yourself, > before (or at the same time as) opening it for reading. What does it mean "open the FIFO for writing yourself"? I've tried putting in the following lines immediately after creating the pipes > byteCountOut <- fdWrite writeOut "#" > (strIn,byteCountIn) <- fdRead readOut 1 > case (byteCountOut,byteCountIn,strIn) of > (1,1,"#") -> done > x -> error ("ChildProcess.999 error"++show x) > > byteCountOut <- fdWrite writeIn "#" > (strIn,byteCountIn) <- fdRead readIn 1 > case (byteCountOut,byteCountIn,strIn) of > (1,1,"#") -> done > x -> error ("ChildProcess.9998 error"++show x) which just write a single character down each pipe; unfortunately this doesn't seem to help. Any other suggestions? By the way this is all GHC5.04.1, which seems to be the last FreeBSD version available, at least with pkg_add. Thanks. George Russell

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