[Haskell-cafe] Cabal and DB packages

manu emmanuel.delaborde at citycampus.com
Sun Nov 25 12:49:57 EST 2007


I'm trying to do something that should be fairly simple, installing  
some DB package so I can use MySQL or SQLite.

However I've had troubles building HSQL, HaskellDB and Takusen before  
giving up (I am using ghc 6.8.1 and Cabal-


with HSQL :

     Could not find module `System.Time':
       it is a member of package old-time-, which is hidden

so I added 'old-time' to the 'build-depends' line in the .cabal file

but then it fails building with

Building hsql-1.7...
[1 of 2] Compiling Database.HSQL.Types ( Database/HSQL/Types.hs, dist/ 
build/Database/HSQL/Types.o )

Database/HSQL/Types.hs:134:18: Not in scope: type variable `forall'

Database/HSQL/Types.hs:134:25: Not in scope: type variable `a'

     Illegal operator `.' in type `forall a . (Int
                                               -> FieldDef
                                                  -> (FieldDef ->  
CString -> Int -> IO a) -> IO a)'
       (Use -XTypeOperators to allow operators in types)


At this point, it goes over my head...


What the hell, I'll use HaskellDB and FlatDB, but then I get this  
message while building HaskellDB :

     Illegal signature in pattern: l f a
         Use -XPatternSignatures to permit it

when I add 'PatternSignatures' to the 'Extensions:' line in .cabal,  
it fails configuring with :

Setup.hs: haskelldb.cabal:8: Parse of field 'extensions' failed:

Jeeeesus, nevermind, I'll try Takusen


with Takusen :

$ runhaskell Setup.hs configure

     Could not find module `Distribution.Program':
       Use -v to see a list of the files searched for.

I give up...


Is there any simple way to do it though ? Is there any problems with  
Cabal that I need to work around ?

Help !!


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