[Haskell-cafe] Re: Open unqualified imports
Martijn van Steenbergen
martijn at van.steenbergen.nl
Fri Jan 16 10:37:23 EST 2009
Eyal Lotem wrote:
> B) Code that has open unqualified imports may break when new symbols
> are added to the libraries its importing. This means that libraries
> cannot even be considered backwards compatible if they retain
> semantics, but add new exported names.
This is not as uncommon as might sound and has happened a few times to
me now, one example being hackage package yogurt failing to build on 6.10:
Ambiguous occurrence `empty'
It could refer to either `Data.IntMap.empty', imported from
Data.IntMap at Network/Yogurt/Mud.hs:43:28-32
or `Text.Regex.Posix.empty', imported from
Text.Regex.Posix at Network/Yogurt/Mud.hs:45:0-22
It's taught me to use qualified imports a lot more often.
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