+1
On Thu, Mar 17, 2011 at 3:25 PM, Bas van Dijk
Hello,
I would like to propose making inits and tails less strict:
inits :: [a] -> [[a]] -inits [] = [[]] -inits (x:xs) = [[]] ++ map (x:) (inits xs) +inits xs = [] : case xs of + [] -> [] + x:xs -> map (x:) (inits xs)
tails :: [a] -> [[a]] -tails [] = [[]] -tails xxs@(_:xs) = xxs : tails xs +tails xxs = xxs : case xxs of + [] -> [] + _:xs -> tails xs
Having a lazier inits allows the elegant: nats = map length (inits nats) which loops for the current definition. This definition was due to John Tromp: http://www.mail-archive.com/haskell@haskell.org/msg21044.html
Discussion deadline: 2 weeks.
Regards,
Bas
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