- Libraries - Haskell.org

Re: [Haskell-cafe] cabal --user question
by Isaac Jones 11 Jul '05

11 Jul '05

There's no way to do this yet. The plan is to allow sections in a single package to depend on each-other as in WASH, and for cabal to handle the "local" package.conf business. This feature has the highest priority, and shouldn't be too hard, but is not yet implemented. peace, isaac

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Re: RFC: Time Library 0.1
by pkeeken＠students.cs.uu.nl 11 Jul '05

11 Jul '05

i looked at the Time library, it looks really good and more complete than the current ghc one and i am thinking of using it for a project. But i only seem to miss a function for getting a week number from a calendar date like: ctWeek :: CalendarTime -> Int or is there another way for doing it, i still dont completely get this thing with ISOweek. Peter ps: having more documentation (with clear examples) would be great, which should be the case with all (ghc) documentation! :) > Sorry for the hiatus, my job has left less free time to work on this. > > Please take a look at a first attempt at writing a replacement for the standard time library. > http://semantic.org/TimeLib/ > > Take a look at the Haddock documentation: > http://semantic.org/TimeLib/doc/html/ > > Download the source: > http://semantic.org/TimeLib/TimeLib-0.1.tar.gz > > Or keep up-to-date: > darcs get http://semantic.org/TimeLib/TimeLib/ > > It needs GHC 6.4. Just run "make" to build the library, tests and documentation. There's also a cabal file (as a completely separate build process), but I've been having trouble with that on Mac OS X. > > I'm particularly interested in comments from people who try to write little applications for it. What did you have trouble with? What made no sense? > > Some points: > > 1. There is no leap second table provided, though there is a type (LeapSecondTable) for such things. Any software compiled with a fixed table would soon become out of date. > > 2. There is no table of time-zones provided, since these also change. However, if there's a good way of getting this from the TZ database on the machine, I'll add that. > > It is actually possible to get the local time-zone for any given time, indeed one of the test programs finds your local summertime transitions. The Timezone type includes name, minutes of offset, and a "summertime" flag. > > 3. I allow multiple calendars with the DayEncoding class. GregorianDay is the most obvious instance, but there are some other useful ones such as ISOWeek. And anyone interested in local cultural calendars can plug their own in here. > > 4. The TimeLocale type comes from the already existing System.Locale. > > 5. I've tried to balance simplicity and functionality. Of course, the majority of people will only be interested in ordinary Gregorian date and time, so I have a simple CalendarTime type synonym with associated functions: > http://semantic.org/TimeLib/doc/html/System.Time.Calendar.html#8 > > 6. It's not possible to expunge POSIX time. I've hidden it, but it's used behind the scenes. Why? Because it's the only way to do sensible arithmetic on UTC times without knowing the leap second table and without worrying about one-second offsets. > > 7. I include Data.Fixed which provides a fixed-point arithmetic type (wrapper around Integer). It probably should be in a separate package. It allows dealing with seconds as a single thing, rather than as an integer/picoseconds pair. > > 8. I don't have any text-parsing functionality. This is a fair amount of work, so it would be good to know sensible requirements. > > -- > Ashley Yakeley, Seattle WA > > _______________________________________________ > Libraries mailing list > Libraries(a)haskell.org > http://www.haskell.org/mailman/listinfo/libraries >

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Can Cabal use GHC's preprocessor?
by Brian Smith 11 Jul '05

11 Jul '05

I have some source files which need CPP style preprocessing. Since I am using GHC, I would like to automatically use GHC's preprocessor instead of having to download and install cpphs. For example, I want to "runghc ./Setup.hs haddock" without cpphs installed. However, references to cpphs are hard-coded into Cabal. What is the best way to go about accomplishing this? Thanks, Brian

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Cabal and Tool Dependencies
by Brian Smith 11 Jul '05

11 Jul '05

1. How can I tell what tool dependencies a package has? For example, how can I tell from a .cabal package that Happy 1.14 or later, or Alex 2.0 is required for the package to build properly? I am making a simple tool that uses .cabal files to build programs and I would like to be able to say "This package requires Happy 1.14 to be installed" upon loading the .cabal file (before the user runs "./Setup.hs build"). 2. Is it possible to register binary (executable) packages? For example, I would like to "register" Happy 1.15 with Cabal, somehow, so that Cabal knows what version of Happy I have installed. This would eliminate the need for me to use --with-happy, etc. when configuring. Thanks, Brian

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System.FilePath module
by Isaac Jones 08 Jul '05

08 Jul '05

Greetings. Back in October, there was a discussion on the System.FilePath module that's currently the hidden module Distribution.Compat.FilePath in Cabal: http://www.haskell.org/pipermail/libraries/2004-October/002591.html It was decided that we should not include it as System.FilePath because it was insufficiently consistent, had some confusing corner cases, and some folks felt that FilePath should be an abstract type. A number of people would like to use the FilePath module as it is, and someone has even packaged it up separately, so I think we should move forward in building a module that performs this task. For those who objected at the time, can someone put together a list of requirements for the FilePath module you believe we need? (Perhaps on the Wiki?) FWIW, the module we have is very similar to the SML and Python modules which perform this task, and most likely very similar to other languages' modules. In short, I think this approach works in practice, but not in theory, as Lemmih said on IRC ;) peace, isaac

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docs for System.Posix.IO
by Isaac Jones 07 Jul '05

07 Jul '05

Greetings, I've been working with the System.Posix.IO module and ran into a few things that could use some documentation. I have added some, and it would be nice if folks could verify that I'm not making stuff up. I would actually be happy to paste some of the docs right from the 'read(2)' and 'write(2)' man pages if that's the correct source? I would commit this, but for some reason, 'make html' doesn't work for me no matter how many times I run cvs up, configure, and make. I always get this error: Control/Monad.hs: unknown flags in {-# OPTIONS #-} pragma: _GHC <<ghc: 9110492 bytes, 2 GCs, 72904/72904 avg/max bytes residency (1 samples), 12M in use, 0.00 INIT (0.00 elapsed), 0.01 MUT (0.09 elapsed), 0.00 GC (0.01 elapsed) :ghc>> make[1]: *** [Control/Monad.raw-hs] Error 1 Any advice? peace, isaac Index: System/Posix/IO.hsc =================================================================== RCS file: /home/cvs/root/fptools/libraries/unix/System/Posix/IO.hsc,v retrieving revision 1.15 diff -u -r1.15 IO.hsc --- System/Posix/IO.hsc 7 Feb 2005 12:03:44 -0000 1.15 +++ System/Posix/IO.hsc 6 Jul 2005 21:53:53 -0000 @@ -9,7 +9,10 @@ -- Stability : provisional -- Portability : non-portable (requires POSIX) -- --- POSIX IO support +-- POSIX IO support. These types and functions correspond to the unix +-- functions open(2), close(2), etc. For more portable functions +-- which are more like fopen(3) and friends from stdio.h, see +-- 'System.IO'. -- ----------------------------------------------------------------------------- @@ -82,10 +85,12 @@ -- ----------------------------------------------------------------------------- -- Pipes --- |The 'createPipe' function creates a pair of connected file descriptors. The first --- component is the fd to read from, the second is the write end. --- Although pipes may be bidirectional, this behaviour is not portable and --- programmers should use two separate pipes for this purpose. +-- |The 'createPipe' function creates a pair of connected file +-- descriptors. The first component is the fd to read from, the second +-- is the write end. Although pipes may be bidirectional, this +-- behaviour is not portable and programmers should use two separate +-- pipes for this purpose. May throw an exception if this is an +-- invalid descriptor. createPipe :: IO (Fd, Fd) createPipe = @@ -98,9 +103,11 @@ -- ----------------------------------------------------------------------------- -- Duplicating file descriptors +-- | May throw an exception if this is an invalid descriptor. dup :: Fd -> IO Fd dup (Fd fd) = do r <- throwErrnoIfMinus1 "dup" (c_dup fd); return (Fd r) +-- | May throw an exception if this is an invalid descriptor. dupTo :: Fd -> Fd -> IO Fd dupTo (Fd fd1) (Fd fd2) = do r <- throwErrnoIfMinus1 "dupTo" (c_dup2 fd1 fd2) @@ -116,15 +123,19 @@ data OpenMode = ReadOnly | WriteOnly | ReadWrite +-- |Correspond to some of the int flags from C's fcntl.h. data OpenFileFlags = OpenFileFlags { - append :: Bool, - exclusive :: Bool, - noctty :: Bool, - nonBlock :: Bool, - trunc :: Bool + append :: Bool, -- ^ O_APPEND + exclusive :: Bool, -- ^ O_EXCL + noctty :: Bool, -- ^ O_NOCTTY + nonBlock :: Bool, -- ^ O_NONBLOCK + trunc :: Bool -- ^ O_TRUNC } + +-- |Default values for the 'OpenFileFlags' type. False for each of +-- append, exclusive, noctty, nonBlock, and trunc. defaultFileFlags :: OpenFileFlags defaultFileFlags = OpenFileFlags { @@ -135,9 +146,12 @@ trunc = False } + +-- |Open and optionally create this file. See 'System.Posix.Files' +-- for information on how to use the 'FileMode' type. openFd :: FilePath -> OpenMode - -> Maybe FileMode -- Just x => O_CREAT, Nothing => must exist + -> Maybe FileMode -- ^Just x => creates the file with the given modes, Nothing => the file must exist. -> OpenFileFlags -> IO Fd openFd name how maybe_mode (OpenFileFlags append exclusive noctty @@ -164,10 +178,17 @@ WriteOnly -> (#const O_WRONLY) ReadWrite -> (#const O_RDWR) +-- |Create and open this file in WriteOnly mode. A special case of +-- 'openFd'. See 'System.Posix.Files' for information on how to use +-- the 'FileMode' type. + createFile :: FilePath -> FileMode -> IO Fd createFile name mode = openFd name WriteOnly (Just mode) defaultFileFlags{ trunc=True } +-- |Close this file descriptor. May throw an exception if this is an +-- invalid descriptor. + closeFd :: Fd -> IO () closeFd (Fd fd) = throwErrnoIfMinus1_ "closeFd" (c_close fd) @@ -216,10 +237,10 @@ -- ----------------------------------------------------------------------------- -- Fd options -data FdOption = AppendOnWrite - | CloseOnExec - | NonBlockingRead - | SynchronousWrites +data FdOption = AppendOnWrite -- ^O_APPEND + | CloseOnExec -- ^FD_CLOEXEC + | NonBlockingRead -- ^O_NONBLOCK + | SynchronousWrites -- ^O_SYNC fdOption2Int :: FdOption -> CInt fdOption2Int CloseOnExec = (#const FD_CLOEXEC) @@ -227,6 +248,7 @@ fdOption2Int NonBlockingRead = (#const O_NONBLOCK) fdOption2Int SynchronousWrites = (#const O_SYNC) +-- | May throw an exception if this is an invalid descriptor. queryFdOption :: Fd -> FdOption -> IO Bool queryFdOption (Fd fd) opt = do r <- throwErrnoIfMinus1 "queryFdOption" (c_fcntl_read fd flag) @@ -236,6 +258,7 @@ CloseOnExec -> (#const F_GETFD) other -> (#const F_GETFL) +-- | May throw an exception if this is an invalid descriptor. setFdOption :: Fd -> FdOption -> Bool -> IO () setFdOption (Fd fd) opt val = do r <- throwErrnoIfMinus1 "setFdOption" (c_fcntl_read fd getflag) @@ -256,6 +279,7 @@ mode2Int RelativeSeek = (#const SEEK_CUR) mode2Int SeekFromEnd = (#const SEEK_END) +-- | May throw an exception if this is an invalid descriptor. fdSeek :: Fd -> SeekMode -> FileOffset -> IO FileOffset fdSeek (Fd fd) mode off = throwErrnoIfMinus1 "fdSeek" (c_lseek fd off (mode2Int mode)) @@ -269,6 +293,7 @@ type FileLock = (LockRequest, SeekMode, FileOffset, FileOffset) +-- | May throw an exception if this is an invalid descriptor. getLock :: Fd -> FileLock -> IO (Maybe (ProcessID, FileLock)) getLock (Fd fd) lock = allocaLock lock $ \p_flock -> do @@ -314,11 +339,13 @@ int2mode (#const SEEK_END) = SeekFromEnd int2mode _ = error $ "int2mode: bad argument" +-- | May throw an exception if this is an invalid descriptor. setLock :: Fd -> FileLock -> IO () setLock (Fd fd) lock = do allocaLock lock $ \p_flock -> throwErrnoIfMinus1_ "setLock" (c_fcntl_lock fd (#const F_SETLK) p_flock) +-- | May throw an exception if this is an invalid descriptor. waitToSetLock :: Fd -> FileLock -> IO () waitToSetLock (Fd fd) lock = do allocaLock lock $ \p_flock -> @@ -328,7 +355,10 @@ -- ----------------------------------------------------------------------------- -- fd{Read,Write} -fdRead :: Fd -> ByteCount -> IO (String, ByteCount) +-- | May throw an exception if this is an invalid descriptor. +fdRead :: Fd + -> ByteCount -- ^How many bytes to read + -> IO (String, ByteCount) -- ^The bytes read, how many bytes were read. fdRead _fd 0 = return ("", 0) fdRead (Fd fd) nbytes = do allocaBytes (fromIntegral nbytes) $ \ bytes -> do @@ -339,6 +369,7 @@ s <- peekCStringLen (bytes, fromIntegral n) return (s, n) +-- | May throw an exception if this is an invalid descriptor. fdWrite :: Fd -> String -> IO ByteCount fdWrite (Fd fd) str = withCStringLen str $ \ (strPtr,len) -> do rc <- throwErrnoIfMinus1Retry "fdWrite" (c_write fd strPtr (fromIntegral len))

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RE: docs for System.Posix.IO
by Simon Marlow 07 Jul '05

07 Jul '05

On 06 July 2005 23:00, Isaac Jones wrote: > I've been working with the System.Posix.IO module and ran into a few > things that could use some documentation. I have added some, and it > would be nice if folks could verify that I'm not making stuff up. I > would actually be happy to paste some of the docs right from the > 'read(2)' and 'write(2)' man pages if that's the correct source? Please commit! > I would commit this, but for some reason, 'make html' doesn't work for > me no matter how many times I run cvs up, configure, and make. I > always get this error: > > > Control/Monad.hs: unknown flags in {-# OPTIONS #-} pragma: _GHC > <<ghc: 9110492 bytes, 2 GCs, 72904/72904 avg/max bytes residency (1 > samples), 12M in use, 0.00 INIT (0.00 elapsed), 0.01 MUT (0.09 > elapsed), 0.00 GC (0.01 elapsed) :ghc>> make[1]: *** > [Control/Monad.raw-hs] Error 1 It looks like the compiler in ghc/compiler/ghc-inplace is out of date, because it doesn't understand the OPTIONS_GHC pragma. Perhaps you need to rebuild in ghc/compiler. Maybe you have sticky tags in part of your source tree, or something? Cheers, Simon

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RE: Time Library 0.1
by Simon Marlow 07 Jul '05

07 Jul '05

I just had a little look around, mainly at System.Time.Calendar. I think the structure is rather complicated - I wanted to find out how to get a CalendarTime for "this time tomorrow", and ended up with this: *System.Time.Calendar> let c' = c{ztTime=zttime{dtDay=dtday{gregDay=day+1}}} where { zttime = ztTime c; dtday = dtDay zttime; day = gregDay dtday } and I found that CalendarTime isn't normalised, you have to convert to UTCTime and then back again to get normalisation (does that do proper normalisation?). Perhaps we should have normaliseCalendarTime. It would be useful to provide this: utcToLocalCalendarTime :: UTCTime -> IO CalendarTime (encodeLocalUTC is taken). I guess the main problem is the difficulty of working with CalendarTime due to the complicated type structure in this module. We should aim to make it easy to do common manipulations of CalendarTime (such as those suggested by Brian Smith). Cheers, Simon On 05 July 2005 09:23, Ashley Yakeley wrote: > Sorry for the hiatus, my job has left less free time to work on this. > > Please take a look at a first attempt at writing a replacement for the > standard time library. > http://semantic.org/TimeLib/ > > Take a look at the Haddock documentation: > http://semantic.org/TimeLib/doc/html/ > > Download the source: > http://semantic.org/TimeLib/TimeLib-0.1.tar.gz > > Or keep up-to-date: > darcs get http://semantic.org/TimeLib/TimeLib/ > > It needs GHC 6.4. Just run "make" to build the library, tests and > documentation. There's also a cabal file (as a completely separate > build process), but I've been having trouble with that on Mac OS X. > > I'm particularly interested in comments from people who try to write > little applications for it. What did you have trouble with? What made > no sense? > > Some points: > > 1. There is no leap second table provided, though there is a type > (LeapSecondTable) for such things. Any software compiled with a fixed > table would soon become out of date. > > 2. There is no table of time-zones provided, since these also change. > However, if there's a good way of getting this from the TZ database on > the machine, I'll add that. > > It is actually possible to get the local time-zone for any given time, > indeed one of the test programs finds your local summertime > transitions. The Timezone type includes name, minutes of offset, and > a "summertime" flag. > > 3. I allow multiple calendars with the DayEncoding class. GregorianDay > is the most obvious instance, but there are some other useful ones > such as ISOWeek. And anyone interested in local cultural calendars > can plug their own in here. > > 4. The TimeLocale type comes from the already existing System.Locale. > > 5. I've tried to balance simplicity and functionality. Of course, the > majority of people will only be interested in ordinary Gregorian date > and time, so I have a simple CalendarTime type synonym with associated > functions: > http://semantic.org/TimeLib/doc/html/System.Time.Calendar.html#8 > > 6. It's not possible to expunge POSIX time. I've hidden it, but it's > used behind the scenes. Why? Because it's the only way to do sensible > arithmetic on UTC times without knowing the leap second table and > without worrying about one-second offsets. > > 7. I include Data.Fixed which provides a fixed-point arithmetic type > (wrapper around Integer). It probably should be in a separate package. > It allows dealing with seconds as a single thing, rather than as an > integer/picoseconds pair. > > 8. I don't have any text-parsing functionality. This is a fair amount > of work, so it would be good to know sensible requirements.

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RE: Time Library 0.1
by Simon Marlow 07 Jul '05

07 Jul '05

On 07 July 2005 09:59, Ashley Yakeley wrote: > In article > <3429668D0E777A499EE74A7952C382D103F41FAB(a)EUR-MSG-01.europe.corp.microso > ft.com>, > "Simon Marlow" <simonmar(a)microsoft.com> wrote: > >> The question is, what's the result of encodeUTC for an invalid >> CalendarTime. Does it roll over the out-of-range fields? What >> happens if you ask for Feb 29 in a non-leap year, for example? > > Right now it's undefined. What should it do? I'd say either it should be an error, or the date should be normalised to a valid date by carrying over any out-of-range values. We should have normalisation anyway, so that might be the easiest behaviour to provide. BTW, I think the library is great. As I said before, I'm a little concerned about how easy it is to do calendar calculations, but given the examples you posted earlier my worries might be unfounded. I think it would be great to collect these examples and put them in the documentation for System.Time.Calendar. Cheers, Simon

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RE: Time Library 0.1
by Simon Marlow 07 Jul '05

07 Jul '05

On 06 July 2005 12:01, Tony Finch wrote: > On Wed, 6 Jul 2005, Simon Marlow wrote: > >> I just had a little look around, mainly at System.Time.Calendar. I >> think the structure is rather complicated - I wanted to find out how >> to get a CalendarTime for "this time tomorrow", and ended up with >> this: > > "this time tomorrow" is not well-defined. What happens then the clocks > change? It's well-defined unless the current time doesn't exist tomorrow, which can happen if a DST switch or leap second happens. In these cases I'd expect either (a) a sensible rollover, or (b) an error, or possibly both behaviours to be available. The question is, what's the result of encodeUTC for an invalid CalendarTime. Does it roll over the out-of-range fields? What happens if you ask for Feb 29 in a non-leap year, for example? Cheers, Simon

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