On Tue, 02 Mar 2004 16:59:48 -0800, Iavor S. Diatchki <diatchki@cse.ogi.edu> wrote:
i'd like to suggest that the definition of "intersperse" from the List module be made more lazy.
Good thing, I think that library functions should always be as lazy as possible in their observeable interface (or well documented why they aren't)
intersperse :: a -> [a] -> [a] intersperse _ [] = [] intersperse sep (x:xs) = x : rest where rest [] = [] rest xs = sep : intersperse sep xs
I don't like the generic name "rest" so much, and the function is not as efficient as it could be due to too much matching -- what about:
intersperse :: a -> [a] -> [a] intersperse sep [] = [] intersperse sep (x:xs) = x : prefix sep xs
prefix :: a -> [a] -> [a] prefix sep [] = [] prefix sep (x:xs) = sep : x : prefix sep xs
-- Daan.