In addition to named capture groups, already suggested, there are \gn and \g{n} relative numbered capture group backreferences, where n may be negative or positive.

But I agree that the problem of having users define regexes using any regex construct under the sun and then be able to combine these pieces together in ways that will still "Do What You Want" is formidable. I think that, in the end, you will have to impose (substantial) limitations on what users can define. And yes, please give us some reasonable examples!

Give a man a fish:  <%-(-(-(-<

In reply to Re: Is there an easy way to parse and modify regular expressions programmatically by AnomalousMonk
in thread Is there an easy way to parse and modify regular expressions programmatically by DrWhy

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.