July 2008 - Libraries

GetOpt formatting improvements
by Duncan Coutts 02 Jul '08

02 Jul '08

GetOpt users, I'd like to have Cabal use the standard System.Console.GetOpt but I'd also like the output to look ok. Currently Cabal uses a private modified version of GetOpt with improved formatting and I'd like to get those improvements into the standard one and eliminate the code duplication. Here's what cabal configure looks like with the standard System.Console.GetOpt. This is what it looks like on a standard 80 column console. In particular note that the descriptions wrap around onto the following lines and look ugly. http://hpaste.org/8626 Here's a little snippet: --enable-library-for-ghci Enable compile library for use with GHCi --disable-library-for-ghci Disable compile library for use wit h GHCi --enable-split-objs Enable split library into smaller ob jects to reduce binary sizes (GHC 6.6+) --disable-split-objs Disable split library into smaller o bjects to reduce binary sizes (GHC 6.6+) --enable-executable-stripping Enable strip executables upon instal lation to reduce binary sizes --disable-executable-stripping Disable strip executables upon insta llation to reduce binary sizes --configure-option=OPT Extra option for configure --user Enable doing a per-user installation --global Disable doing a per-user installatio n --package-db=PATH Use a specific package database (to satisfy dependencies and register in) Here's the same but using the internal modified copy of GetOpt: http://hpaste.org/8626#a1 and the same snippet: --enable-library-for-ghci Enable compile library for use with GHCi --disable-library-for-ghci Disable compile library for use with GHCi --enable-split-objs Enable split library into smaller objects to reduce binary sizes (GHC 6.6+) --disable-split-objs Disable split library into smaller objects to reduce binary sizes (GHC 6.6+) --enable-executable-stripping Enable strip executables upon installation to reduce binary sizes --disable-executable-stripping Disable strip executables upon installation to reduce binary sizes --configure-option=OPT Extra option for configure --user Enable doing a per-user installation --global Disable doing a per-user installation --package-db=PATH Use a specific package database (to satisfy dependencies and register in) So there's two things to notice. One is that we wrap the description so it fits in 80 columns. The other is that we use one space rather than two of padding between the short options, the long options and the description. This gives more space for the description. Actually we go one step further and leave off the args on the short options since they're shown on the long options anyway. I'm not sure everyone wants that so I'm not really proposing it. This is what it looks like: -f FLAGS --flags=FLAGS Force values for the given... vs -f --flags=FLAGS Force values for the given flags in... Similarly: -v[n] --verbose[=n] Control verbosity (n is 0--3,... vs -v --verbose[=n] Control verbosity (n is 0--3, default... So if people think this is sensible I'll send three patches: 1. word-wrap the description to fit in 80 columns 2. use less padding between columns 3. omit the args on short options when there is also a corresponding long option though as I say, perhaps not everyone will think the 3rd change is the right thing to do. Duncan

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Error accessing data files from package code in Cabal: Unkown symbol
by Alfonso Acosta 02 Jul '08

02 Jul '08

Hi! I'm working on a library package called ForSyDe. Following Cabal's documentation, I'm using the autogenerated Paths_ForSyDe module in order to access the data files of my library during execution. After installation, the Paths_ForSyDe import seems to be causing an unknown-symbol error whenever I try to compile any code which makes use of the ForSyDe library: " unknown symbol `___stginit_ForSyDezm0zi1_PathszuForSyDe_' " I'm not sure, but it seems that cabal doesn't properly link or install the Paths_ForSyDe module (I tried to include it in the cabal description file to no avail) Any suggestions about how to fix this problem? Thanks in advance, Fons P.S: I'm using Cabal-1.2.3.0

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Takusen build error
by Benjamin Franksen 02 Jul '08

02 Jul '08

I get a strange error building Takusen (more precisely: the module Foreign/C/UTF8.hs) with ghc-6.8.3. It says aragon: .../ghc-6.8.3/Takusen-0.8.1 > ./Setup build -v Reading parameters from /srv/projects/ctl/franksen/haskell/ghc-6.8.3/Takusen-0.8.1/takusen.buildinfo Creating dist/build (and its parents) Creating dist/build/autogen (and its parents) Preprocessing library Takusen-0.8.1... Building Takusen-0.8.1... Building library... Creating dist/build (and its parents) Creating dist/build (and its parents) /projects/ctl/franksen/usr/bin/ghc -package-name Takusen-0.8.1 --make -hide-all-packages -i -idist/build/autogen -idist/build -i. -Idist/build -I/opt/oracle/product/client/rdbms/demo -odir dist/build -hidir dist/build -stubdir dist/build -package base-3.0.2.0 -package mtl-1.1.0.1 -package time-1.1.2.1 -package old-time-1.0.0.0 -O -XCPP Database.Enumerator Database.Util Database.Oracle.Enumerator Database.Oracle.OCIConstants Database.Oracle.OCIFunctions Database.Stub.Enumerator Control.Exception.MonadIO Foreign.C.UTF8 Database.InternalEnumerator [1 of 9] Compiling Foreign.C.UTF8 ( Foreign/C/UTF8.hs, dist/build/Foreign/C/UTF8.o ) /tmp/ghc18936_0/ghc18936_0.s: Assembler messages: /tmp/ghc18936_0/ghc18936_0.s:1257:0: Error: symbol `base_GHCziBase_Z0T_closure' is already defined I compiled ghc-6.8.3 from source, using ghc-6.8.2 to bootstrap. Any ideas? Cheers Ben

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