(slightly modified the version with guards so that it will make backwards ranges too)
Revision as of 05:22, 20 November 2010
Create a list containing all integers within a given range.
range x y = [x..y]
range = enumFromTo
range x y = take (y-x+1) $ iterate (+1) x
range start stop | start > stop = reverse (range stop start) | start == stop = [stop] | start < stop = start:range (start+1) stop
Since there's already syntactic sugar for ranges, there's usually no reason to define a function like 'range' in Haskell. In fact, the syntactic sugar is implemented using the enumFromTo function, which is exactly what 'range' should be.