October 2009 - Glasgow-haskell-users

IP issues in writing a ghci adaption?
by Christopher Svanefalk 21 Oct '09

21 Oct '09

Hey everyone, If one wants to write a ghci-like application for the C++ language (and/or other languages as well FTM), which is not a derivative work of the ghci source, are there any intellectual property issues that need to be addressed? For example, would this tool be allowed to use similar syntax and commands as those in ghci (:r, :l etc), have a similar name (gcci?), carry some specific license, etc, or is the field clear? The reason I am asking is of course that I am currently working on something like this (although it will probably differ from ghci in terms of design, implementation, features etc) so I am thankful for any answers! kind regards, Christopher Svanefalk, Student (comp.sc.), Univeristy of Gothenburg, Sweden.

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The template-haskell@haskell.org mailing list
by Simon Peyton-Jones 21 Oct '09

21 Oct '09

Question: is the template-haskell(a)haskell.org mailing list still useful? * It has 250 subscribers compared to 850 for ghc-users. * It has low traffic * template-haskell is the only GHC-specific mailing list associated with a particular language feature. Eg type functions, ghci, etc do not have their own list * The traffic on ghc-users is not dauntingly high. I suggest we abolish it in favour of ghc-users. Any dissenters? (I'd emit a warning, so that people could check they are subscribed to ghc-users.) Simon

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RE: [Template-haskell] How to extract name and type of exported functions in modules
by Simon Peyton-Jones 21 Oct '09

21 Oct '09

[ccing ghc-users] | I'm trying to extract the names and types of exported functions in a module. Quite a reasonable request. But it's not conveniently possible at the moment. Here's what you can do in the Q monad: class (Monad m, Functor m) => Quasi m where -- Fresh names qNewName :: String -> m Name -- Error reporting and recovery qReport :: Bool -> String -> m () -- Report an error (True) or warning (False) -- ...but carry on; use 'fail' to stop qRecover :: m a -> m a -> m a -- Recover from the monadic 'fail' -- The first arg is the error handler -- Inspect the type-checker's environment qReify :: Name -> m Info qLocation :: m Loc -- Input/output (dangerous) qRunIO :: IO a -> m a But you want one more function: qReifyModule :: String -> m ModuleInfo where ModuleInfo is something like: data ModuleInfo = MI { mi_exports :: [Name] , ... instances,rules, etc } Then you could use qReify to get info about a particular thing. This would not be hard in principle, the details need thought. For example, if module exports T( C1, C2), where C1, C2 are constructors of T which also has constructors C3, C4, what should appear in mi_exports? Should mi_exports reflect the structure of the export list (see the AvailInfo type in GHC). What is the info for an instance? Do we need a way to ask for all the instances of a class (or rules for a function) regardless of what module those instances come from? etc Does this ring bells for anyone else? Would someone like to write the spec? Are there other reify-related things that we need? Simon | -----Original Message----- | From: template-haskell-bounces(a)haskell.org [mailto:template-haskell- | bounces(a)haskell.org] On Behalf Of Oscar Finnsson | Sent: 16 October 2009 18:47 | To: template-haskell(a)haskell.org | Subject: [Template-haskell] How to extract name and type of exported functions in | modules | | Hi, | | I'm trying to extract the names and types of exported functions in a module. | | At the moment I've managed to get a list of all functions in a module | but I can't seem to figure out how to get their types. | | Lets say I got the module | | module Foo where | | foo1 :: String -> String | foo1 value = value | | foo2 = "hej" | | and then in anothor module... | | module Bar where | | bar = $(getAllFunctions "<some-path>/Foo.hs") | | At the moment I got getAllFunctions returning ["foo1","foo2"], but I | would really like to get it to return [("foo1",AppT (ConT "String") | (ConT "String")), ("foo2",ConT "String")] | | Using "parseModuleWithMode" from Language.Haskell.Exts I can get hold | of the names and the type signature of foo1 (since it's specified in | the source code) but I cannot get hold of the type signature of foo2 | (since it's not specified in the source code). | | Is there another way to get the names/signatures of exported functions | from a module other than using parseModuleWithMode so the developer | writing the Foo-module isn't forced to explicitly supply type | signatures of the exported functions? | | If I try "reify" to get information about the functions I get the error message: | "foo1 is not in scope at a reify" | | This seems to be a known bug about reify (reported here | http://hackage.haskell.org/trac/ghc/ticket/2339) My problem is that I | cannot use the workaround since I don't know the name of the | functions. | | Another disadvantage with this approach is that "getAllFunctions" must | have access to the source code of the module and that I must supply | the path the the module. If possible I would like to have code such as | | bar = $(getAllFunctions "Foo") | | instead of "<come-path>/Foo.hs". | | Regards, | Oscar Finnsson | _______________________________________________ | template-haskell mailing list | template-haskell(a)haskell.org | http://www.haskell.org/mailman/listinfo/template-haskell

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6.12.1rc1: non-Latin filenames in GHCi
by Chryssochoidis Christos 20 Oct '09

20 Oct '09

I've noticed that when I load in GHCi a file that has a non-latin name, although it gets loaded, its name appears garbled in the message after the loading: > Prelude> :load πρόχειρον.hs > [1 of 1] Compiling Main ( ÏÏÎ > ¿ÌÏÎµÎ¹ÏÎ¿Î½.hs, interpreted ) > Ok, modules loaded: Main. > *Main> Is this expected, or something is wrong with my setup? It's a rather insignificant issue, but I thought to ask about it. I'm using GHC 6.12.1rc1 on Mac OS X 10.6.1. Thanks very much, Christos Chryssochoidis

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Broken link in GHC page
by Marco Túlio Gontijo e Silva 20 Oct '09

20 Oct '09

Hi. The link to the mailing list on the GHC page is not correct. It should link to http://www.haskell.org/ghc/docs/latest/html/users_guide/mailing-lists-GHC.h… instead of http://www.haskell.org/ghc/docs/latest/html/users_guide/introduction-GHC.ht… . Greetings. -- marcot http://marcot.iaaeee.org/

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TAG IN 6.8
by Aswad, Mustafa 20 Oct '09

20 Oct '09

Hi I am try update GUM But I have problem with Tagging and Untagging closures any can direct me to a document to understand the tagging procedure. best washes -- Heriot-Watt University is a Scottish charity registered under charity number SC000278.

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[Fwd: Re: [Gtk2hs-devel] Help with build on Alpha]
by Marco Túlio Gontijo e Silva 19 Oct '09

19 Oct '09

Hi. I sent a mail to gtk2hs-devel about this bug, and I'm forwarding it's response to here. Greetings. -------- Mensagem encaminhada -------- De: Axel Simon <Axel.Simon(a)ens.fr> (...) On Sep 27, 2009, at 18:02, Marco Túlio Gontijo e Silva wrote: (...) > I don't have a clue about this bug: > http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=540879 . Do you have > any idea about what could be causing this? (...) This is a limitation of ghc. So you should ask the ghc people if they can fix this. Then we could think of a work-around. But the only workaround there is is not to bind functions that are affected by the limitation. That would pretty much rule out all modules in ModelView/ which is a rather important part of Gtk2Hs. (...) -- marcot http://marcot.iaaeee.org/

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STM experiment
by Luca Ciciriello 14 Oct '09

14 Oct '09

Hi All. I'm very new using Concurrency and STM in Haskell. I'm trying some basic example using STM like this one: module Main where import IO import Control.Concurrent import Control.Concurrent.STM main :: IO () main = do forkIO (hPutStr stdout "Hello") hPutStr stdout " world\n" Loading this module in GHCi and running main, the result is: wHoerllldo On MacOs X 10.5.8 and on WindowsXp Compiling this module with: ghc --make Main.hs -o Main and launcing ./Main the result is just: Terminal> world Am I doing something wrong? My expected result was Hello world (or world Hello) Thanks in advance for any answer. Luca.

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Attempts to install libraries with GHC 6.12.1rc1
by Neil Brown 13 Oct '09

13 Oct '09

Hi, I downloaded the new GHC release candidate. It compiled and installed first time, which was great. However, this is not true of all the libraries. I'm posting here in the hope that it helps other users trying to get it to work, or library maintainers to see what breaks in the new compiler. I know most people should wait for the Haskell platform, but I'm happy to jump through hoops to try the release candidate. So, after installing GHC, I tried to bootstrap cabal-install with the bootstrap.sh script, but that told me it required parsec and network. (I have since seen a post on this list that cabal-install won't work, but anyway....) Parsec (and mtl, which it needed) installed fine with 6.12.1-rc1. The network package said: Network/Socket.hsc:1707:45: Not in scope: data constructor `System.Posix.Internals.Stream' (I also tried the latest version of network from the darcs repository, but that said: Warning: defaultUserHooks in Setup script is deprecated. Configuring network-2.2.1.4... Warning: The 'build-type' is 'Configure' but there is no 'configure' script. Setup.hs: Missing dependency on a foreign library: * Missing header file: HsNet.h Even though HsNet.h is in the include directory already... odd. ) Anyway, it looked like that Posix module was in the unix library, so I thought I'd install that. That said: Preprocessing library unix-2.3.2.0... gcc: unrecognized option '-R/home/nccb2/lib/ghc-6.12.0.20091010/base-4.2.0.0' gcc: unrecognized option '-R/home/nccb2/lib/ghc-6.12.0.20091010/integer-gmp-0.2.0.0' gcc: unrecognized option '-R/home/nccb2/lib/ghc-6.12.0.20091010/ghc-prim-0.2.0.0' gcc: unrecognized option '-R/home/nccb2/lib/ghc-6.12.0.20091010' gcc: unrecognized option '-R/home/nccb2/lib/ghc-6.12.0.20091010' #... Above 5 lines repeated a lot of times #gcc --version is 4.3.3 Building unix-2.3.2.0... dist/build/System/Posix/Signals.hs:127:0: error: Signals.h: No such file or directory I searched for Signals.h on my file system: /home/nccb2/ghc-6.10.4/includes/Signals.h /home/nccb2/lib/ghc-6.10.4/include/Signals.h /home/nccb2/lib/ghc-6.12.0.20091010/include/rts/Signals.h /home/nccb2/ghc-6.12.0.20091010/includes/rts/Signals.h /home/nccb2/ghc-6.12.0.20091010/rts/posix/Signals.h So I tried configuring with --extra-include-dirs=/home/nccb2/lib/ghc-6.12.0.20091010/include/rts which got further, but that said: [13 of 21] Compiling System.Posix.IO ( dist/build/System/Posix/IO.hs, dist/build/System/Posix/IO.o ) System/Posix/IO.hsc:217:11: Not in scope: `haFD' System/Posix/IO.hsc:218:2: Not in scope: `flushWriteBufferOnly' System/Posix/IO.hsc:219:2: Not in scope: `unlockFile' System/Posix/IO.hsc:223:13: `haFD' is not a (visible) constructor field name These functions seem to have gone in base-4, so I changed the unix.cabal file's base-depends to base < 4. That takes away the unlockFile error, but the others remain. Which is odd, because flushWriteBufferOnly is in GHC.Handle in base-3, which System/Posix/IO.hsc imports. So now I'm stuck. Can anyone say what the fix is that I need to apply to the unix package to get it working? Thanks, Neil. P.S. parallel, stm, HUnit and QuickCheck-2 all installed fine too.

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Should ghci understand this pthread library?
by Maurício CA 12 Oct '09

12 Oct '09

After using ghci to load a library I'm working in, I got this message: can't load .so/.DLL for: pthread (/usr/lib/libpthread.so: invalid ELF header) Then I did 'cat /usr/lib/libpthread.so' and, much to my surprise, it's a text file with the following contents: /* GNU ld script Use the shared library, but some functions are only in the static library, so try that secondarily. */ OUTPUT_FORMAT(elf32-i386) GROUP ( /lib/libpthread.so.0 /usr/lib/libpthread_nonshared.a ) Is this a standard file? Should ghci be able to understand it and, maybe, use the listed libraries instead? Thanks, Maurício

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