It's backtracking like crazy. The \w+ gobbles up as many characters as it can, but then the {$x} quantifier forces it to backtrack one character in order to form two (\w+) sequences. That does not yield enough sequences to satisfy the {$x}, so it backtracks another character. The newly freed character is then gobbled up by the second group. We still don't have {$x} groups. Now the second group backtracks and concedes a character to allow for the matching of a third group. That's still not $x groups. So we backtrack.. and so on.. and so forth..

Make that \w{$x}, which is what you obviously wanted, and you'll see it works fine.

Makeshifts last the longest.

In reply to Re: regexp hang? by Aristotle
in thread regexp hang? by cxreg

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.