>>>>> "O" == Oleg <oleg at okmij.org> writes: O> and require the boilerplate of writing functor instances Just note, since DeriveFunctor there is almost never any such boilerplate in these cases. -- John Wiegley GPG fingerprint = 4710 CF98 AF9B 327B B80F http://newartisans.com 60E1 46C4 BD1A 7AC1 4BA2