Robert Klemme
7/13/2007 8:22:00 AM
2007/7/13, Daniel N <has.sox@gmail.com>:
> On 7/13/07, Robert Klemme <shortcutter@googlemail.com> wrote:
> >
> > 2007/7/13, Daniel N <has.sox@gmail.com>:
> > > Hi,
> > >
> > > I'm looking through the Merb::Routing code and I've found a regexp that
> > I
> > > can't figure out how it works.
> > >
> > > Merb::Router::SECTION_REGEXP #=> /(?::([a-z*_]+))/
> > >
> > > It takes a route definition string, like "/products/:model/:id" and
> > > extracts the "model" string on the first pass, and later the "id"
> > string.
> > >
> > > Can anyone shed some light on what the
> > > ?::
> > > part does? I haven't found it in any of the documentation for Ruby
> > Regexps
> > > that I've found.
> >
> > It's actually *two* parts: (?:) is a non capturing regexp group. The
> > second ":" literally matches a single colon.
> >
> > Kind regards
> >
> > robert
> >
> > Thanx Robert,
>
> I've not heard of that before. Makes searching on google much easier :)
>
> /(?::([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.
Exactly. Btw, in your case I'd probably use another regexp. Some samples:
irb(main):001:0> "/products/:model/:id".scan %r{/:([^/]+)}
=> [["model"], ["id"]]
irb(main):002:0> "/products/:model/:id".scan %r{:([^/]+)}
=> [["model"], ["id"]]
irb(main):004:0> "/products/:model/:id".scan %r{:[^/:]+}
=> [":model", ":id"]
But of course I do not know the full spec of your input data.
Kind regards
robert