pkgDB :: ReadM PackageDB
pkgDB = do
    s <- str
    pure $ case s of
        "global" -> GlobalPackageDB
        "user" -> UserPackageDB
        _ -> SpecificPackageDB s
pkgDB :: ReadM PackageDB
pkgDB = do
    s <- str
    pure $ case s of
        "global" -> GlobalPackageDB
        "user" -> UserPackageDB
        _ -> SpecificPackageDB s
pkgDB = do
    s <- str
    pure $ case s of
        "global" -> GlobalPackageDB
        "user" -> UserPackageDB
        _ -> SpecificPackageDB s