I am sure this has been asked before, but I couldn't find the answer on my own.

Very simply, I want to do a substitution where the string being substituted in, is based on what was matched; in other (clearer) words, it would look like: s/(bar)/&foo($1)/g;.

The best I've been able to come up with is: s/((bar)(?{$b=foo($2)}))/$b/g;

I am a little wary of this, as I am not entirely certain that I understand exactly how it's doing what it's doing (additionaly the docs seem to suggest that (?{}) is liable to open the gates of hell and unleash all sorts of despair on humanity). Additionally, as I understand it, this requires a global variable (the use of $b is quite intentional here).

So my question is: (a) am I going to run into trouble with the above? and (b) is there a better way?

In reply to manipulating capture groups in s/// by glwtta

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.