December 2008 - Haskell-Cafe

GHC on Fedora 10 - getMBlock: mmap: Permission denied
by Fraser Wilson 03 Dec '08

03 Dec '08

Hi all, Has anybody seen this? I thought it might be an SELinux thing, but then I wouldn't expect GHC or darcs to run. Audley is a fairly simple program in operating system feature terms, but I get the same error with anything I build myself. [fraser@astroboy audley]$ ./dist/build/audley/audley audley: internal error: getMBlock: mmap: Permission denied (GHC version 6.8.3 for i386_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Aborted [fraser@astroboy audley]$ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.8.3 [fraser@astroboy audley]$ cat /proc/version Linux version 2.6.27-0.352.rc7.git1.fc10.i686 ( mockbuild(a)x86-5.fedora.phx.redhat.com) (gcc version 4.3.2 20080917 (Red Hat 4.3.2-4) (GCC) ) #1 SMP Tue Sep 23 21:26:04 EDT 2008 [fraser@astroboy audley]$ cheers, Fraser. -- http://thewhitelion.org/mysister

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is there something special about the Num instance?
by Anatoly Yakovenko 03 Dec '08

03 Dec '08

module Test where --why does this work: data Test = Test class Foo t where foo :: Num v => t -> v -> IO () instance Foo Test where foo _ 1 = print $ "one" foo _ _ = print $ "not one" --but this doesn't? class Bar t where bar :: Foo v => t -> v -> IO () instance Bar Test where bar _ Test = print $ "test" bar _ _ = print $ "not test"

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Re: [Haskell-cafe] is there something special about the Num instance?
by Yuriy 03 Dec '08

03 Dec '08

Numeric literals are special. Their type is (Num t) => t, so it can belong to any type that is instance of Num. Whereas Test belongs to Test type only so you cannot call bar on any instance of Foo. So your pattern constrains type signature of bar more then it is constrained by class declaration. On Wed, Dec 03, 2008 at 03:05:37PM -0800, Anatoly Yakovenko wrote: > module Test where > --why does this work: > data Test = Test > > class Foo t where > foo :: Num v => t -> v -> IO () > > instance Foo Test where > foo _ 1 = print $ "one" > foo _ _ = print $ "not one" > > --but this doesn't? > > class Bar t where > bar :: Foo v => t -> v -> IO () > > instance Bar Test where > bar _ Test = print $ "test" > bar _ _ = print $ "not test" > _______________________________________________ > Haskell-Cafe mailing list > Haskell-Cafe(a)haskell.org > http://www.haskell.org/mailman/listinfo/haskell-cafe

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Re: [Haskell-cafe] library to process zip files
by Yuriy 03 Dec '08

03 Dec '08

Almost as fast as typing "proper" google query :) Thanks. On Wed, Dec 03, 2008 at 06:01:59PM -0500, Jeff Heard wrote: > http://hackage.haskell.org/cgi-bin/hackage-scripts/package/zip-archive > > On Wed, Dec 3, 2008 at 5:59 PM, Yuriy <yuriy.halytskyy(a)gmail.com> wrote: > > On Thu, Dec 04, 2008 at 11:56:10AM +1300, Yuriy wrote: > > Hi, > > > > Is there any haskell library to work with ZIP file format? > > > > Thanks, > > Yuriy > > _______________________________________________ > > Haskell-Cafe mailing list > > Haskell-Cafe(a)haskell.org > > http://www.haskell.org/mailman/listinfo/haskell-cafe > >

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library to process zip files
by Yuriy 03 Dec '08

03 Dec '08

On Thu, Dec 04, 2008 at 11:56:10AM +1300, Yuriy wrote: Hi, Is there any haskell library to work with ZIP file format? Thanks, Yuriy

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Problem building HXQ on Mac OS 10.5.5
by Tobias Kräntzer 03 Dec '08

03 Dec '08

Hi, I'm new to haskell and wonted to start tinkering a bit with this language, specifically with HXQ. I have installed ghc with macports. Now while building HXQ I get the following error: Main.hs:20:9: Not in scope: type constructor or class `C.SomeException' Unfortunately I'm also new to Mac OS X. Before I developed on Linux. It would be great, if someone could give me a hint. Thanks, Tobias PS: Below the details -- ~$ cabal install hxq Resolving dependencies... 'HXQ-0.11.0' is cached. Configuring HXQ-0.11.0... Preprocessing library HXQ-0.11.0... Preprocessing executables for HXQ-0.11.0... Building HXQ-0.11.0... . . . Loading package haskell98 ... linking ... done. [20 of 21] Compiling Text.XML.HXQ.XQuery ( src/Text/XML/HXQ/XQuery.hs, dist/build/xquery/xquery-tmp/Text/XML/HXQ/XQuery.o ) [21 of 21] Compiling Main ( Main.hs, dist/build/xquery/ xquery-tmp/Main.o ) Main.hs:20:9: Not in scope: type constructor or class `C.SomeException' cabal: Error: some packages failed to install: HXQ-0.11.0 failed during the building phase. The exception was: exit: ExitFailure 1 -- ~$ ghc-pkg list /opt/local/lib/ghc-6.10.1/./package.conf: Cabal-1.6.0.1, HUnit-1.2.0.3, QuickCheck-1.2.0.0, array-0.2.0.0, base-3.0.3.0, base-4.0.0.0, bytestring-0.9.1.4, containers-0.2.0.0, directory-1.0.0.2, (dph-base-0.3), (dph-par-0.3), (dph-prim-interface-0.3), (dph-prim-par-0.3), (dph-prim-seq-0.3), (dph-seq-0.3), editline-0.2.1.0, filepath-1.1.0.1, (ghc-6.10.1), ghc-prim-0.1.0.0, haddock-2.3.0, haskell-src-1.0.1.3, haskell98-1.0.1.0, hpc-0.5.0.2, html-1.0.1.2, integer-0.1.0.0, mtl-1.1.0.2, network-2.2.0.1, old-locale-1.0.0.1, old-time-1.0.0.1, packedstring-0.1.0.1, parallel-1.1.0.0, parsec-2.1.0.1, pretty-1.0.1.0, process-1.0.1.0, random-1.0.0.1, regex-base-0.72.0.2, regex-compat-0.71.0.1, regex-posix-0.72.0.3, rts-1.0, stm-2.1.1.2, syb-0.1.0.0, template-haskell-2.3.0.0, time-1.1.2.2, unix-2.3.1.0, xhtml-3000.2.0.1 /Users/tobias/.ghc/i386-darwin-6.10.1/package.conf: readline-1.0.1.0 -- Tobias Kräntzer info(a)tobias-kraentzer.de

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handles and foreign C functions
by Andrea Rossato 03 Dec '08

03 Dec '08

Hello, suppose a simple C function like this: void printStuff(FILE *f) { fprintf (f, "Hello World\n"); } In order to use it I need to import fopen and pass to it a Ptr CFile: foreign import ccall unsafe "fopen" fopen :: CString -> CString -> IO (Ptr CFile) foreign import ccall unsafe "fclose" fclose :: Ptr CFile -> IO CInt foreign import ccall unsafe "printStuff" printStuff :: Ptr CFile -> IO () main = withCString "tmp.txt" $ \cpath -> withCString "w" $ \cmode -> do cfile <- throwErrnoIfNull "fopen: " (fopen cpath cmode) printStuff cfile fclose cfile How can I pass to printStuff a stdout FILE pointer? If, for instance, I do: foreign import ccall unsafe "stdout" c_stdout :: Ptr CFile main = withCString "tmp.txt" $ \cpath -> withCString "w" $ \cmode -> do printStuff c_stdout I get a segmentation fault. What am I missing? TIA Andrea

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Re: [Haskell-cafe] Problem building HXQ on Mac OS 10.5.5
by Tobias Kräntzer 03 Dec '08

03 Dec '08

Hi, Am 03.12.2008 um 02:00 schrieb Gwern Branwen: > I haven't looked at the source, so take this as off-the-cuff: try > importing not Control.Exception but Control.OldException. changing "Control.Exception"to "Control.OldException" didn't work. But changing "SomeException" to "Exception" seems to solve the problem (see below). At least I can now built it and use xquery. I think these days I get more in to it and understand what I was doing. ;-) Could it be a problem with the version of GHC? I'm using 6.10.1. Is "SomeException" still supported? At the moment I don't know how to look these things up. Regard, . . . Tobias -- Original: #if __GLASGOW_HASKELL__ >= 609 type E = C.SomeException #else type E = C.Exception #endif -- Modified: type E = C.Exception -- Tobias Kräntzer | Scharnweberstraße 52a | 10247 Berlin Telefon: +49-30-75636668 | +49-178-1353136 XMPP: anagrom_ataf(a)jabber.ccc.de

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Cabal and Hat?
by Magnus Therning 03 Dec '08

03 Dec '08

Is it possible to use cabal to build the files that hat would need to do tracing (i.e. .htx files)? /M -- Magnus Therning (OpenPGP: 0xAB4DFBA4) magnus＠therning．org Jabber: magnus＠therning．org http://therning.org/magnus identi.ca|twitter: magthe

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ByteString web site papers
by Galchin, Vasili 03 Dec '08

03 Dec '08

Hello, http://www.cse.unsw.edu.au/~dons/fps.html Are the papers/slides still up-to-date for someone to get up-to-speed on ByteString motivation and implementation? Anything more recent? Regards, Vasili

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