Doug McIlroy points out: | trivial bug (inaccurate error comment) in Prelude.hs: | | Prelude> ([]::[Int]) !! -1 | | Program error: PreludeList.!!: index too large This is really a bug in the Haskell report, which defines (!!) thus: (x:_) !! 0 = x (_:xs) !! n | n > 0 = xs !! (minusInt n 1) (_:_) !! _ = error "Prelude.(!!): negative index" [] !! _ = error "Prelude.(!!): index too large" I propose to treat this as another H98 Report typo, and change the defn to xs !! n | n < 0 = error "Prelude.(!!): negative index" [] !! _ = error "Prelude.(!!): index too large" (x:_) !! 0 = x (_:xs) !! n | n > 0 = xs !! (minusInt n 1) Does anyone object? (I'm still trying to get round to consolidating the H98 revisions into a revised report.) Simon
