2007/7/13, James Edward Gray II <james / grayproductions.net>:
> On Jul 13, 2007, at 3:12 AM, Daniel N wrote:
>
> > /(?::([a-z*_]+))/
> >
> > I guess this means that a nested group within this non capturing
> > group (this
> > case) is captured though since the $1 variable is refered to later.
>
> Yes.  The part without the colon is capture, because of the normal
> parenthesis.
>
> Unless this expression is later embedded in another expression, the
> non-capturing group does nothing here and could safely be removed.

Even in that case the grouping can be removed:

irb(main):002:0> /foo/.to_s
=> "(?-mix:foo)"
irb(main):003:0> /(?:foo)/.to_s
=> "(?-mix:foo)"

Kind regards

robert