Thanks for the writeup!

But a small nitpick... =)

On May 15, 11:26 am, Matthew Moss <matthew.m...@[...].com>  wrote:
>        puts @tape.sort.map {|_,v| v}.join.gsub(/^_*|_*$/, '')
> 
>  "useful" content of the tape is displayed. Chen's regular expression
>  (slightly corrected in the code shown above), removes all blanks
>  immediately after the start of the line _or_ immediately preceding the
>  end of the line.

Shouldn't the regex return "a" instead of "a_b" for "_a_b_"?