December 2007 - Libraries

Case-insensitive formats for Data.Time.Format?
by Bjorn Buckwalter 26 Dec '07

26 Dec '07

Hello all, Is there a compelling reason to not make the formats in Data.Time.Format case-insensitive when parsing? This would apply to the months, weekdays, time zone. (I see there are already two formats %p and %P corresponding (confusingly) to AM/PM and am/pm respectively.) What got me thinking about this is that I'm being supplied with dates on the format "26 DEC" which will not parse without munging. I suspect such situations are fairly common? Also, is there a way to have the parser assume a century of 20 with the format %y? Thanks, Bjorn

2 2

getOpt return record of type a rather than [a]
by Henning Thielemann 19 Dec '07

19 Dec '07

The current version of System.Console.GetOpt.getOpt returns a list of values, where the element type has usually one constructor per option. data Flag = Verbose | Version | Input String | Output String | LibDir String What I more like to receive is a record consisting of one constructor and many fields, where optional options are of type Maybe, options with multiple occurrence are of type list. data Flag = Flag { verbose :: Bool, version :: Bool, input :: Maybe FilePath, output :: Maybe FilePath, libdir :: FilePath } Then we would need data ArgDescr a = NoArg (a -> a) ReqArg (String -> a -> a) String OptArg (String -> a -> a) String e.g. OptArg (\path flags -> flags {input = Just path}) "FILE" I feel this approach is so natural, that someone must have implemented it already.

5 7

Build Log Question
by Dominic Steinitz 17 Dec '07

17 Dec '07

I was about to update the crypto package when I noticed that there is now a "build log" on each package page. What does this mean and what should I do as package maintainer? Many thanks, Dominic. >> Step 1 - configuring Crypto-3.0.3 > > Configuring Crypto-3.0.3... > Setup.hs: At least the following dependencies are missing: > NewBinary -any > >>> Terminated due to an error. >>> Step 1 - configuring ASN1-0.0.1 > > Configuring ASN1-0.0.1... > Setup.hs: At least the following dependencies are missing: > NewBinary -any > >>> Terminated due to an error.

2 1

hierarchical module names
by Henning Thielemann 12 Dec '07

12 Dec '07

From http://haskell.org/haskellwiki/How_to_write_a_Haskell_program#Hierarchical_… there is a link to http://www.haskell.org/~simonmar/lib-hierarchy.html It looks a bit out of date (no Control.Arrow, but DSP instead of Sound). Is there a more current list?

2 2

making haddock docs with inter-package links?
by Conal Elliott 10 Dec '07

10 Dec '07

I have a bunch of libraries I'd like to re-release (via hackage & darcs) with haddock 2.0 docs. Each package has doc links within the package, to ghc libs, other packages on cabal, and to some packages with haddock docs in other places (wxhaskell, in particular). Is there any way for me to get all of these links working? And if not, is there a solution in the works? Thanks, - Conal

1 0

cabal, haddock, and --hyperlink-source
by Conal Elliott 09 Dec '07

09 Dec '07

I'm getting an error message with cabal's haddock command's --hyperlink-source option. The message (below) says "haddock --hyperlink-source requires Haddock version 0.8 or later", while "haddock --version" says that I have version 2.0. I have the latest cabal and hscolour from hackage and the latest haddock from darcs. I'm using cygwin on WinXP. bash-3.2$ ./setup haddock --hyperlink-source --verbose Creating dist\doc\html\reactive (and its parents) Preprocessing library reactive-0.0... Running hscolour for reactive-0.0... Creating dist\doc\html\reactive\src (and its parents) c:\Haskell\packages\bin\HsColour.exe -print-css -odist\doc\html\reactive\src\hscolour.css c:\Haskell\packages\bin\HsColour.exe -css -anchor -odist\doc\html\reactive\src\Data-IVar.html src\Data\IVar.hs Creating dist\doc\html\reactive\src (and its parents) c:\Haskell\packages\bin\HsColour.exe -print-css -odist\doc\html\reactive\src\hscolour.css c:\Haskell\packages\bin\HsColour.exe -css -anchor -odist\doc\html\reactive\src\Data-Fun.html src\Data\Fun.hs Creating dist\doc\html\reactive\src (and its parents) c:\Haskell\packages\bin\HsColour.exe -print-css -odist\doc\html\reactive\src\hscolour.css c:\Haskell\packages\bin\HsColour.exe -css -anchor -odist\doc\html\reactive\src\Data-Reactive.html src\Data\Reactive.hs Creating dist\build\tmp (and its parents) Creating dist\doc\html\reactive (and its parents) Preprocessing library reactive-0.0... Running Haddock for reactive-0.0... setup.exe: haddock --hyperlink-source requires Haddock version 0.8 or later bash-3.2$ haddock --version Haddock version 2.0, (c) Simon Marlow 2003; ported to the GHC-API by David Waern 2006 bash-3.2$ Ideas? - Conal

4 4

Fwd: [GHC] #1960: Add Applicative and Monoid instances for STM
by Conal Elliott 08 Dec '07

08 Dec '07

Is STM part of the libraries(a)haskell.org charter? ---------- Forwarded message ---------- From: GHC <trac(a)galois.com> Date: Dec 5, 2007 2:57 PM Subject: [GHC] #1960: Add Applicative and Monoid instances for STM To: Cc: glasgow-haskell-bugs(a)haskell.org #1960: Add Applicative and Monoid instances for STM -------------------------------+-------------------------------------------- Reporter: conal | Owner: Type: proposal | Status: new Priority: normal | Milestone: Component: libraries/base | Version: 6.8.1 Severity: normal | Keywords: Difficulty: Easy (1 hr) | Testcase: Architecture: Unknown | Os: Unknown -------------------------------+-------------------------------------------- {{{ instance Applicative STM where { pure = return; (<*>) = ap } instance Monoid (STM a) where { mempty = retry; mappend = orElse } }}} I don't know where these instances would go. Nor whether this is a libraries or GHC proposal. -- Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1960> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 0

Documentation and HAppS
by Chris Smith 08 Dec '07

08 Dec '07

I'm making an offer. I need to learn HAppS extremely well over the next couple months. I am willing to document the process by attempting to write detailed documentation on developing applications with HAppS. Something on the order that could be eventually combined into a book, or at least an extensive searchable web site. My current thoughts are to either: 1. Find a free wiki site to do it. 2. Use HaskellWiki 3. Coordinate with Alex regarding the HAppS web site I'm not sure which would be most appropriate. My hope would be to make this public early, since I'm bound to make some mistakes or leave some things out. So I'm sort of counting on getting comments from people who know more than me. Finally, I'm not sure whether code currently in a sufficiently good state that it would be reasonable to write something like this. Perhaps I should hold off and wait for things to stabilize. So: - Is this something people would find helpful? - Should I do it now, or wait? - Which of the choices (1), (2), or (3) above do you think best of? Thanks, -- Chris Smith

1 1

mtl documentation - external link broken
by apfelmus 07 Dec '07

07 Dec '07

Hello, In the documentation for the monad transformer library, the hyperlink http://www.cse.ogi.edu/~mpj/ to Mark P. Jones' homepage is broken. It's used to reference his paper Functional Programming with Overloading and Higher-Order Polymorphism The new location is http://web.cecs.pdx.edu/~mpj/ Regards, apfelmus

1 0

Cabal, System.Filepath
by Peter Gammie 06 Dec '07

06 Dec '07

To my surprise, if you type ^C at the right moment you can trash GHC's (system-wide) package list. I figured it was easier to reinstall than fix, but forgot Debian installs GHC 6.6 if I don't ask for "unstable". So, let's get Cabal on its feet again: $ ghc --version The Glorious Glasgow Haskell Compilation System, version 6.6 $ darcs pull Pulling from "http://darcs.haskell.org/cabal"... No remote changes to pull in! $ ghc -i. --make Setup.lhs -o setup Distribution/Simple.hs:114:7: Could not find module `System.FilePath': Use -v to see a list of the files searched for. Can I humbly suggest that Cabal rely on very few external libraries? (I'm switching to 6.6.1 as I type this.) cheers peter

2 4