Some shake cabal stuff I don't need

shake-cabal

mkPackageRule packageDir = do
    desc      <- parseCabalPackage packageDir
    let version      = show $ pkgVersion $ package desc
        srcs         = collectSrcs       desc
        dependencies = collectDeps       desc
        libPath      = [str|cabal-dev/lib/libHS$packageDir$-$version$.a|]
    want libPath
    libPath *> \_ -> do
        need $ srcs ++ dependencies
        system' "cabal-dev"  ["install", packageDir ++ "/", "--force-reinstalls", 
                                    "--enable-tests"]

collectDeps desc = result where
    --get the dependencies for the whole thing
    --get the dependencies for the library, executable, and tests
    libDeps = targetBuildDepends $ libBuildInfo desc
    libDeps = targetBuildDepends $ libBuildInfo desc
  
collectSrcs desc = result where
    Just libDesc = library desc
    executables' = executables decs
    testSuites'  = testSuites  decs
    result       = libSrcs libDesc 
                        ++ (concatMap executableSrcs executables')
                        ++ (concatMap testSuiteSrcs  testSuites' )
                        
libSrcs        = collectBuildInfoSrcs . libBuildInfo 
executableSrcs = collectBuildInfoSrcs . buildInfo 
testSuiteSrcs  = collectBuildInfoSrcs . testBuildInfo
    
collectBuildInfoSrcs buildInfo = do 
    concat <$> mapM (\srcDir -> matchFileGlob $ FileGlob srcDir ".hs") srcs
                               
parseCabalPackage packageDir = do
    pdfile <- findPackageDesc packageDir
    ppd    <- readPackageDescription verbosity pdfile
    return $ flattenPackageDescription ppd