I'm a regular expression novice. In a recent thread on word wrapping, there
were posts that included the following regexp:

/.{1,50}(?:\s|\Z)/

... after dinking with this, it seems the ?: causes a backward search from
the end. 

1) Is my assumption correct?

2) Is this documented anywhere? It seems to be missing from the pickaxe book
and one of the perl docs I found
(http://www.perl.com/pub/doc/manual/html/pod/perlre.html) after others
mentioned perl & ruby regexp are similar doesn't mention ?: at all. 

Chris Morris
chrism / snellingcorp.com