Nothing, in this case. *g* It will just fail a notch faster in cases where it can't match.

The reason is that once the (;\d+)* stops, if what follows isn't an m, the regex engine will backtrack, giving up a bit of what (;\d+)* matched, trying to find an m. Of course we know that neither the semicolon nor \d can match something that is an m, so no backtracking in the world is going to help and make it match.

What (?>re) does is throw away all the intermediate states once re has matched, so if backtracking seems necessary, the engine will not remember how to backtrack into the middle of re. Effectively, if the engine fails to find an m after the (?>re), it will unmatch re all at once, rather than waste time doing so character by character.

Makeshifts last the longest.

In reply to Re^3: Removing ANSI Color Codes (atomic grouping) by Aristotle
in thread Removing ANSI Color Codes by narse

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.