Distribution/Types/PackageId.hs

    {-# LANGUAGE GeneralizedNewtypeDeriving #-}
    {-# LANGUAGE DeriveDataTypeable #-}
    {-# LANGUAGE DeriveGeneric #-}
    module Distribution.Types.PackageId
      ( PackageIdentifier(..)
      , PackageId
      ) where

    import Prelude ()
    import Distribution.Compat.Prelude

    import Distribution.Version
             ( Version, nullVersion )

    import qualified Distribution.Compat.ReadP as Parse
    import qualified Text.PrettyPrint as Disp
    import Distribution.Compat.ReadP
    import Distribution.Text
    import Distribution.Types.PackageName

    -- | Type alias so we can use the shorter name PackageId.
    type PackageId = PackageIdentifier

    -- | The name and version of a package.
    data PackageIdentifier
        = PackageIdentifier {
            pkgName    :: PackageName, -- ^The name of this package, eg. foo
            pkgVersion :: Version -- ^the version of this package, eg 1.2
         }
         deriving (Generic, Read, Show, Eq, Ord, Typeable, Data)

    instance Binary PackageIdentifier

    instance Text PackageIdentifier where
      disp (PackageIdentifier n v)
        | v == nullVersion = disp n -- if no version, don't show version.
        | otherwise        = disp n <<>> Disp.char '-' <<>> disp v

      parse = do
        n <- parse
        v <- (Parse.char '-' >> parse) <++ return nullVersion
        return (PackageIdentifier n v)

    instance NFData PackageIdentifier where
        rnf (PackageIdentifier name version) = rnf name `seq` rnf version