12 Jan
2012
12 Jan
'12
2:37 a.m.
Direct recursion is almost always clearer if you are traversing the
list at a "different speed". The usual list functionals (map, filter,
folds) are all speed 1 - traversing one element at a time. Here we
want pairwise traversal:
unscan :: (a -> a -> b) -> [a] -> [b]
unscan f (a:b:bs) = f a b : unscan f b bs
unscan _ _ = []
On 12 January 2012 06:41, Kyle Murphy
I was able to build something incredibly convoluted that accomplishes what you want, but I'm sure there's a better way to do it.
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