From: Kyle Schmitt <kyleaschmitt@...>
Date: 2008-05-14T00:59:20+09:00
Subject: detail on a regex?

Is there a way to pull details out of a regular expression's failure?

I'm running into a situation where I've got some validation methods,
and I'm resorting to passing in both a regular expression and a range.
 I know quite well I could just use a range inside of a regex, and
would rather, but I need to get the range in order to have some useful
error messages.

For example, the string must be 3 to 8 characters long, start with a
letter, and may contain letters numbers or dashes.

I would like to just use this:
some_string=~/^[a-z][-a-z0-9]{2,7}$/i

But if the match fails, I can't give out any good error messages
without further inspecting the string, so I end up with
some_string=~/^[a-z][-a-z0-9]$/i
[3..8].include?some_string.length

Just so I can give reasonable error messages.

--Kyle