On Sun, Aug 12, 2012 at 11:18 AM, Janne Hellsten <jjhellst@gmail.com> wrote:
I note that postgresql-simple and mysql-simple use ByteStrings
exclusively in the API.
No, that's not how they work. The underlying representation in some places might be a ByteString, but the actual APIs don't use ByteStrings, they go through typeclasses.