Thanks David,
all3 ls = do a <- ls b <- ls c <- ls return (a,b,c)
For each element a of list ls , for each element b of the same list ls, and for each element c of the same list ls, make a tuple of them. return the list of tall the tuples.
But it is a bit more complicated. I changed the result to [a,b,c] in order to have variable length results. I am now trying to get a "allN ls n" function that returns the result for the original problem with "allN [0..5] 3" and all combinations of the form [a,b] with "allN [0..5] 2". So basically I want a variable number of name bindings in the list comprehension. Is this possible in a (simple) way using the list monad? Maybe like allN ls n = foldr (>>=) [] (replicate n ls) >>= return regards, Matthias -- __________________________________________________________ ___ __ __ Dipl. Inf. Matthias Guedemann / __\/ _\ /__\ Computer Systems in Engineering / / \ \ /_\ Otto-von-Guericke Universitaet Magdeburg / /___ _\ \//__ Tel.: 0391 / 67-19359 \____/ \__/\__/ __________________________________________________________