Reverse an array. Recursive implementation, tail call modulo cons

00_reverse.rb

def reverse(ary)
  return ary unless ary.length > 1
  reverse(ary[0...ary.length-1]).unshift(ary[-1])
end

reverse.ml

let rec reverse xs = match xs with
  | []          -> []
  | [x]         -> [x]
  | head::tail  -> reverse tail @ [head]