Hal Daume III
What sent me first into deep confusion is that I found all of {Text,GHC}.{Read,Show} first, and the Read classes marked as "nonportable GHC extensions". Quite disheartening :-( Well, then I found the Prelude definition (though it's entirely unclear how they relate to the Text and GHC versions).
The GHC versions are simply more efficient versions. Show and Read are completely portable.
AIIEE! Now they tell me -- I've optimized one of my programs, and it now spends most of it's time 'read'ing. So the thing is just to import GHC(read) instead of using the Prelude version? I guess it's worth a try (although I expect I really need to go to binary IO) -kzm -- If I haven't seen further, it is by standing in the footprints of giants