On 13/05/2012 10:07, Joseph Wright wrote:
>   \tl_count:N     => \tl_length:N
>   \tl_count:c     => \tl_length:c
>   \tl_count:n     => \tl_length:n
>   \tl_count:V     => \tl_length:V
>   \tl_count:o     => \tl_length:o

These should of course have gone the other way, so

  \tl_length:N => \tl_count:N

and so on.
-- 
Joseph Wright