On Tue, Mar 24, 2009 at 1:42 PM, Manlio Perillo
But, as an example, when you read a function like:
buildPartitions xs ns = zipWith take ns . init $ scanl (flip drop) xs ns
that can be rewritten (argument reversed) as:
takeList :: [Int] -> [a] -> [[a]] takeList [] _ = [] takeList _ [] = [] takeList (n : ns) xs = head : takeList ns tail where (head, tail) = splitAt n xs
I think that there is a problem.
This crops up all the time even in simple mathematics. One way to provide assistance to newcomers is to provide a quasi-English reading of the notation. Take as an example a simple set comprehension expression (using Z email notation, http://csci.csusb.edu/dick/samples/z.lexis.html): { x : Int | 0 < x < 10 /\ x %e Odd @ 2*x } That's pretty opaque for beginners until they learn to read | as "such that", %e as "member of" and @ as "generate", so that they can express the idea in quasi-English: "form a set by taking all integers x such that ... and ..., then generate the result by doubling them" or the like. Or take | as "filter" and @ as "map"; the point is it helps to be able to express it in something like natural language. Do something similar for your buildPartitions definition and I'll bet you'll end up with something much more user friendly than takeList. -gregg