- Glasgow-haskell-users

Haddock, .lhs, and GHC
by Richard Giraud 16 Jun '08

16 Jun '08

Hello I did a little digging on this issue and didn't find a definitive answer. According to the Haddock page in the wiki, Haddock is the de facto way of documenting files [http://haskell.org/haskellwiki/Haddock] Does this mean that literate source files should be discouraged? They seem to be fairly common, especially in conjunction with Cabal (i.e., Setup.lhs). They also appear in quite a few beginner tutorials, which can send new users down the wrong path (e.g., http://haskell.org/haskellwiki/How_to_write_a_Haskell_program) Is there an effort and/or intent to move the GHC sources away from .lhs entirely? --- The reason I ask is: I'm looking at the Test.HUnit modules and there are no Haddock annotations. I thought I'd help document the modules but, when I had a look at the source files, I found they were .lhs instead of .hs. There is already some documentation in the files but it's not visible to Haddock. What's the best way to proceed in a case like this? 1. Shoe-horn in the Haddock annotations by putting them in the code sections (e.g., > -- | Document comment...) but this seems a little cumbersome, especially if these comments show up in the published form of the .lhs file. 2. Rename to the files to .hs and touch up the files so they compile, then add the Haddock annotations. 3. Another option? --- I get the feeling that HUnit isn't getting much attention. Is that because it's "done" or because it's obsolete and will soon be removed? Thanks, Richard G.

4 6

Problems interrupting IO with -threaded
by Judah Jacobson 16 Jun '08

16 Jun '08

Hi all, I'm writing a program that reads input from the user but should also handle a ctrl-c. My attempt is below; the program forks a thread to read one character of input, and kills that thread upon receiving a sigINT. It works fine compiled without -threaded, but with -threaded it blocks forever after a ctrl-c. I know that in general, foreign calls are not interruptible; but the documentation for Control.Concurrent and System.Timeout suggests that I/O operations are a special case. In particular, the documentation for System.Timeout.timeout says: "Standard I/O functions like hGetBuf, hPutBuf, Network.Socket.accept, or hWaitForInput appear to be blocking, but they really don't because the runtime system uses scheduling mechanisms like select(2) to perform asynchronous I/O, so it is possible to interrupt standard socket I/O or file I/O using this combinator." So is the behavior that I'm seeing correct? If so, it seems odd to get better concurrency without the threaded runtime. If not, I can file a bug for this. I used ghc-6.8.2 and HEAD on OS X 10.5 (x86). Thanks, -Judah -------------- module Main where import Control.Monad import System.Posix.Signals import Control.Concurrent import Control.Concurrent.MVar import System.IO main = do hSetBuffering stdin NoBuffering hSetEcho stdin False mv <- newEmptyMVar let handler = putMVar mv Nothing installHandler sigINT (CatchOnce handler) Nothing tid <- forkIO (myGetChar mv) c <- takeMVar mv when (c==Nothing) $ do killThread tid putStrLn ("Result: " ++ show c) myGetChar mv = do c <- getChar putMVar mv (Just c)

4 5

6.8.3: make framework-pkg doesn't work
by Deborah Goldsmith 15 Jun '08

15 Jun '08

I tried building 6.8.3, and just "make" worked, but when I tried "make framework-pkg" I got stuff like this: > <com.apple.tools.info-plist-utility> "/Users/chak/Code/ghc/ > distrib/MacOS/Info copy.plist" -expandbuildsettings -o /Users/debbie/ > Work/source/ghc-6.8.3/distrib/MacOS/build/Release/GHC.framework/ > Versions/608/Resources/Info.plist I don't have a user named "chak" on my system, so it looks like there are some hardwired paths in the Xcode project for this target. I'm trying "make framework-binary-dist" and that appears to be working better. Deborah

1 0

Record syntax and INLINE annotations
by Bryan O'Sullivan 13 Jun '08

13 Jun '08

I have a curious situation. I've defined a data type using record syntax, and my module exports one of the accessor functions. I notice that GHC is not inlining any of the others, even though they are not exported. Furthermore, while poking around to see if I could bend it to my will, I found that I couldn't figure out where to place an INLINE annotation for an accessor function defined via record syntax such that the compiler would accept it. For now, I've dropped back to non-record syntax, my hand-crafted accessors are being inlined as I'd expect, and I win a few percent in performance. If anyone could shed a wee bit of light, I'd be most grateful.

3 4

desperately seeking RULES help
by Conal Elliott 09 Jun '08

09 Jun '08

I'm trying to do some fusion in ghc, and I'd greatly appreciate help with the code below (which is simplified from fusion on linear maps). I've tried every variation I can think of, and always something prevents the fusion. Help, please! Thanks, - Conal {-# OPTIONS_GHC -O2 -Wall -fglasgow-exts -ddump-simpl -ddump-simpl-stats #-} -- {-# OPTIONS_GHC -ddump-simpl-iterations #-} module F where -- | Domain of a linear map. class AsInt a where toInt :: a -> Int fromInt :: Int -> a {-# RULES "toInt/fromInt" forall m. toInt (fromInt m) = m #-} {-# INLINE onInt #-} onInt :: AsInt a => (Int -> Int) -> (a -> a) onInt f = fromInt . f . toInt test :: AsInt a => (Int -> Int) -> (Int -> Int) -> (a -> a) test h g = onInt h . onInt g -- The desired result: -- -- test h g -- == onInt h . onInt g -- == (fromInt . h . toInt) . (fromInt . g . toInt) -- == \ a -> (fromInt . h . toInt) ((fromInt . g . toInt) a) -- == \ a -> (fromInt . h . toInt) (fromInt (g (toInt a))) -- == \ a -> fromInt (h (toInt (fromInt (g (toInt a))))) -- == \ a -> fromInt (h (g (toInt a)))

7 17

Missing Data.Map library? GHC 6.8.2 under OS X
by Thomas Krauss 09 Jun '08

09 Jun '08

I seem to be having trouble using GHC 6.8.2 and OS X (10.5). It seems that any use of anything from Data.Map results in a link error like Undefined symbols: "___stginit_containerszm0zi1zi0zi1_DataziMap_", referenced from: ___stginit_Main_ in tst_parse.o ld: symbol(s) not found Has anyone else seen this? I tried reinstalling the package from haskell.org, but no luck.

4 3

Building ndp Problem
by Dominic Steinitz 09 Jun '08

09 Jun '08

I wanted to try out data parallel haskell. I followed the instructions on http://haskell.org/haskellwiki/Data_Parallel_Haskell/PackageNDP but I get the following error: > dom@lagrange:~/ghc/libraries> make make.library.ndp > make: *** No rule to make target `build.library.ndp', needed by `make.library.ndp'. Stop. BTW when I built ghc, I had the following problem with happy (and alex). It kept telling me I needed dvips but dvips is already installed. In the end I used --nodeps. > dom@lagrange:~/happy> rpmbuild -ta happy-1.17.tar.gz > error: Failed build dependencies: > dvips is needed by happy-1.17-1.i586 > dom@lagrange:~/happy> rpmlocate dvips > /usr/bin/dvips > dom@lagrange:~/happy> rpm --query -f /usr/bin/dvips > texlive-2007-69 > dom@lagrange:~/happy> dvips --version > dvips(k) 5.96 > kpathsea version 3.5.6 > Copyright (C) 2005 Radical Eye Software. > There is NO warranty. You may redistribute this software > under the terms of the GNU General Public License > and the Dvips copyright. > For more information about these matters, see the files > named COPYING and dvips.h. > Primary author of Dvips: T. Rokicki; -k maintainer: T. Kacvinsky/ S. Rahtz. > rpmbuild -ta --nodeps happy-1.17.tar.gz

3 4

*BSD support in 6.8.3
by Simon Marlow 07 Jun '08

07 Jun '08

Hi Folks, 6.8.3 is nearing release, and we have an outstanding bug affecting the GHCi on the BSDs: http://hackage.haskell.org/trac/ghc/ticket/2013 We need someone to help out with this. The patch in the ticket apparently works, but can't be committed as is because it isn't correctly #ifdef'd and will presumably break other platforms. Also it needs to be tested on OpenBSD/NetBSD in addition to FreeBSD. I don't have access to a *BSD machine right now, and I don't have the time available to set one up. If someone can donate a temporary account then that would be helpful, but most helpful would be if someone could work with us to get this bug fixed in time for 6.8.3 (i.e. the next few days). Otherwise, we have to release with the bug still in, which would be bad. Cheers, Simon

6 19

Mutually recursive modules
by Richard Giraud 06 Jun '08

06 Jun '08

Hello I've been doing some work with mutually recursive modules (MRMs). I'm familiar with the section in the User's Guide on how to do this and have successfully worked with MRMs with simple dependencies. However, I have created a set of MRMs that I can't seem to get to compile because of type issues. I can get the code to compile by combining all of the modules into a single, monolithic module; however, this breaks the conceptual design that I'm going for. I may also be able to break the modules into smaller pieces that will compile, though I'm not sure about this and it, too, would break the conceptual design. Does the current {-# SOURCE #-}/.hs-boot scheme allow for compilation of arbitrary MRMs? Or are there known cases where it doesn't work? If there are cases where it doesn't work, are there other options? Someone in Haskell Cafe mentioned that GHC 6.2 used a different scheme for MRMs (.hi-boot). Is it still possible to use this? Would it allow for compilation of arbitrary MRMs? I can create a minimal case as an example, if it would be useful. Thanks, Richard

4 3

automatically deriving Functor Re[2]: [Haskell-cafe] automatically deriving Map and Filter on datatypes etc.
by Bulat Ziganshin 05 Jun '08

05 Jun '08

Hello Neil, Thursday, June 5, 2008, 8:54:51 PM, you wrote: >> PS Why isn't Functor derivable? > Derive can do it: http://www.cs.york.ac.uk/~ndm/derive > I believe that Twan (the author of Functor deriving in Derive) is > trying to get this suggested for Haskell' as a proper deriving. dear GHC developers, may be it's a good idea to add such facility to ghc? [as one more H98 extension] -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com

1 0