function my::mkdir_p (
  String $directory
) {
  $directory.split("/").reduce([]) |$parents, $child| {
    if !($child == "") {
      $new_dir = $parents.join("/")

      if $new_dir != "" {
        if !(defined(File[$new_dir])) {
          file{$new_dir:
            ensure => "directory"
          }
        }
      }
    }

    $parents + $child
  }

  file{$directory:
    ensure => "directory"
  }
}

my::mkdir_p("/tmp/some/set/of/dirs")
my::mkdir_p("/tmp/some/set/of/other/dirs")