:: Eq a => [a] -> [[a]] package:utility-ht
This function is lazier than the one suggested in the Haskell 98
report. It is inits undefined = [] : undefined, in contrast
to Data.List.inits undefined = undefined.
This function is lazier than the one suggested in the Haskell 98
report. It is tails undefined = ([] : undefined) : undefined,
in contrast to Data.List.tails undefined = undefined.