- Libraries - Haskell.org

darcs patch: fix failure to compile with cabal included with ghc 6.6
by David Roundy 20 May '07

20 May '07

I'm not sure if this is sufficient, or even a good idea, but removing this type signature makes Setup.hs able to run on my system with an older cabal. David Wed May 16 09:18:47 PDT 2007 David Roundy <droundy(a)darcs.net> * fix failure to compile with cabal included with ghc 6.6

4 5

darcs patch: add test that X11 will actually build.
by David Roundy 20 May '07

20 May '07

Just for future benefits, it seems a good idea to occasionally check that the X11 library actually can be built. This patch is untested, since the X11 library won't build for me. David Wed May 16 09:26:26 PDT 2007 David Roundy <droundy(a)darcs.net> * add test that X11 will actually build.

2 1

terminateProcess
by Johannes Waldmann 18 May '07

18 May '07

according to documentation of System.Process.terminateProcess, "This function should not be used under normal circumstances." Well, then what function then *should* be used normally? I have the following code in a multithreaded Haskell program, which does not work (if this thread is killed, the external process keeps running after the Haskell program exits) bracket ( System.Process.runCommand cmd ) ( terminateProcess p ) ( polling_waitForProcess ) It took me a while to figure out why "waitForProcess" here does not work: Control.Concurrent.throwTo says "If the target thread is currently making a foreign call, then the exception will not be raised (and hence throwTo will not return until the call has completed.") That's why I defined let polling_waitForProcess p = do me <- getProcessExitCode p case me of Just e -> return () Nothing -> do threadDelay ( 10^5 ) polling_waitForProcess p any hints appreciated, J.W.

2 1

Proposal: ByteString based datagram communication (Ticket #1238 )
by Robert Marlow 18 May '07

18 May '07

I've made a proposal to add ByteString based datagram communication to Network.Socket and Network. Details are at: http://hackage.haskell.org/trac/ghc/ticket/1238#preview I rushed to get this done before I go on a trip tomorrow so I haven't completed testing and won't be available to discuss it for the next 9 days. As such, if discussion is needed, an extended deadline would be appreciated. Testing windows is a bit awkward for me since I don't have a windows machine, so if anyone can test that platform I'd be very appreciative. I'll try to work through the problems I was having with hugs and test when I get back unless someone else wants to test it first. Thanks. -- Robert Marlow MITS Co-operative Limited http://www.mits.coop/

7 23

darcs patch: fix failure to compile with cabal includ... (and 1 more)
by David Roundy 16 May '07

16 May '07

Here's a fixed patch for testing that X11 actually builds. This time it calls autoreconf as the README instructs. David Wed May 16 09:18:47 PDT 2007 David Roundy <droundy(a)darcs.net> * fix failure to compile with cabal included with ghc 6.6 Wed May 16 09:55:02 PDT 2007 David Roundy <droundy(a)darcs.net> * add fixed test that X11 builds

1 0

cgi-compat and ghc-6.6.1
by Johannes Waldmann 15 May '07

15 May '07

What is the status of cgi-compat with ghc-6.6.1? I have some older code that wants Network.CGI.Compat, which seems not available in ghc-6.6.1 standard installation. When I build cgi-compat from source cgi-compat-2006.9.6.tar.gz it will complain about missing "fps". I delete this requirement from cgi.cabal and then can build and install. But now when I compile my program, the message is Could not find module `Network.CGI.Compat': it was found in multiple packages: cgi-compat-2006.9.6 cgi-3001.1.1 I can ghc-pkg hide cgi-3001.1.1 and that seems to solve it for the moment. If I find the time, I probably should change my sources to use the newer API - is there a "migration guide" somewhere? Best regards, Johannes Waldmann.

2 1

Is there already a list class?
by Marc Weber 13 May '07

13 May '07

Hello. Is here the right place to request a list class? eg class List l e where (:) :: e -> l e -> l e head :: .. This might be used in Data.Set, Data.Map class StorableAsList l e t where fromList :: l e -> t toList :: t -> l e I'd like to help implementing/ writing it. Do you consider this beeing a useful enhancement? Cheers Marc Weber

12 20

The Proper Definition of (evaluate :: a -> IO a)
by Isaac Dupree 11 May '07

11 May '07

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 The obvious "evaluate x = x `seq` return x" fails one of the following laws for evaluate: " evaluate x `seq` y ==> y evaluate x `catch` f ==> (return $! x) `catch` f evaluate x >>= f ==> (return $! x) >>= f Note: the first equation implies that (evaluate x) is not the same as (return $! x). " However, strictness does not obey the monad laws. A correct definition for IO would be "evaluate x = (x `seq` return x) >>= return", or equally, "(return $! x) >>= return", or even more horrible-looking, "fmap id (return $! x)"! This works because (at least in present Haskell implementations) IO's (>>=) is not strict in its first argument. Noticing that this function has been implemented (slightly wrongly) for NHC in base, so I mention this odd suggestion. Isaac -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGPHKtHgcxvIWYTTURAmT2AKC+pipeHff1jVOCqxjOOz2p+6/JqQCeNqAN bjkaLwbn+BRVCya2e49diF4= =J9iV -----END PGP SIGNATURE-----

6 9

Re: Fwd: Report this to bug-autoconf@gnu.org
by Simon Marlow 10 May '07

10 May '07

Forwarding to list on behalf of "Marek Burza" <mkburza(a)gmail.com>. > ---------- Forwarded message ---------- > From: "Marek Burza" <mkburza(a)gmail.com <mailto:mkburza@gmail.com>> > To: libraries(a)haskell.org <mailto:libraries@haskell.org> > Date: Thu, 10 May 2007 09:50:23 +0200 > Subject: Fwd: Report this to bug-autoconf(a)gnu.org > <mailto:bug-autoconf@gnu.org> > Hi, > > When I tried to install network package an error ocurred to me > below you can find a more detailed description on what it is and how it > can be fixed > - I figured you might be interested > > Best regards, > Mark > > ---------- Forwarded message ---------- > From: *Ralf Wildenhues* < Ralf.Wildenhues(a)gmx.de > <mailto:Ralf.Wildenhues@gmx.de>> > Date: 10-May-2007 08:59 > Subject: Re: Report this to bug-autoconf(a)gnu.org > <mailto:bug-autoconf@gnu.org> > To: Marek Burza < mkburza(a)gmail.com <mailto:mkburza@gmail.com>> > Cc: bug-autoconf(a)gnu.org <mailto:bug-autoconf@gnu.org> > > Hello Marek, > > Thanks for the report. > > * Marek Burza wrote on Wed, May 09, 2007 at 05:57:45PM CEST: > > > > I was trying to install an extension (network-2.0) to Haskell on cygwin > > and I got an error or warning which requested to be reported to you :) > > You can see the output below and if you need more info I'll be glad to > > provide it to you. > [...] > > > checking winsock.h usability... no > > checking winsock.h presence... yes > > configure: WARNING: winsock.h: present but cannot be compiled > > configure: WARNING: winsock.h: check for missing prerequisite headers? > > configure: WARNING: winsock.h: proceeding with the preprocessor's result > > configure: WARNING: ## ------------------------------------ ## > > configure: WARNING: ## Report this to bug-autoconf(a)gnu.org > <mailto:bug-autoconf@gnu.org>. ## > > configure: WARNING: ## ------------------------------------ ## > > checking for winsock.h... yes > [...] > > Please read > > http://www.gnu.org/software/autoconf/manual/html_node/Present-But-Cannot-Be… > > and then show that to the maintainer of the Haskell package, who can > fix this in his package. The error becomes clearer if you look at the > part of the config.log file that deals with this compile failure (and > maybe also some Cygwin documentation). > > > nlv13536@NLVEHVRES2DT1C9 $ runghc Setup.hs build > > Preprocessing library network-2.0.. . > > Building network-2.0... > > cbits\ancilData.c: In function `sendFd': > > > > cbits\ancilData.c:47:0: > > error: variable `msg' has initializer but incomplete type > [...] > > FWIW, these may or may not be followup errors; I don't know. > > Cheers, > Ralf >

1 0

problems using ghc-6.6.1 (due to fgl-5.4.1)
by Christian Maeder 09 May '07

09 May '07

I wrote: > Dear Hets- and GHC-Developers, > we have a problem using ghc-6.6.1. The created hets binary runs a > couple > of times slower than the one created using ghc-6.6. This problem is gone when I install and use fgl-5.3 (where "hiding (indices)" needs to be deleted in Data.Graph.Inductive.Monad.IOArray). I strongly suspect the new functions context1l' and context4l' in Data.Graph.Inductive.Graph (fgl-5.4.1) to be the reason for our drastic slow down. In fgl-5.3 the functions fst4 and fth4 have been used instead. A cyclic edge (an edge from and to the very same node) was only returned as ingoing edge and not as outgoing one. (a design decision documented elsewhere). I think, the change in fgl-5.4.1 now returns a cyclic edge also as outgoing edge (and possibly twice as ingoing one). Our application heavily uses in- and outgoing edges that may be cyclic. Christian P.S. ghc-6.6.1/libraries/fgl/Setup.hs does not compile with ghc-6.6.1

2 2