[Haskell-cafe] is it possible to implement Functor for ByteString and Text

[silvio]

cool trick. This is by far the best solution yet. Of course it's a bit
deceptive in what you are working with. E.g.

bs1 <- pack [1..10]
print bs1
let bs2 = map (+1) bs1
print bs2
let bs3 = map (+1) bs2
print bs3
...
let bsn = map (+1) bsn_1
print bsn

will have quadratic complexity. On the other, hand you will get fusion
for free.

silvio