Nice analysis. :-)

A few nits however, for the regex versions you should state which handles what. For instance only demsRE and demsRE_o will handle negative numbers. Also the timing results would be more interesting if more cases were handled. Including fail cases. Ie, what happens if there are 3 numbers, or 5? Yada yada...

But they are just nits. nice work.

--- demerphq
my friends call me, usually because I'm late....