Task

Write a function to flatten the nesting in an arbitrary list of values.

Your program should work on the equivalent of this list:

  [[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []]

Where the correct result would be the list:

   [1, 2, 3, 4, 5, 6, 7, 8]

Related task

   Tree traversal


 
templates flatten
  [ $ -> # ] !
  when <[]> do
    $... -> #
  otherwise
    $ !
end flatten
 
[[1], 2, [[3, 4], 5], [[[]]], [[[6]]], 7, 8, []] -> flatten -> !OUT::write
 