Without testing I'd have to say that I would not be surprised if Perl really was slower. Perl also tends to lose on complex regular regular expressions to CL-PPCRE for Perl 5.6 on up. And probably others.

However take the string ("foo " x 100)."fo" and try to match it to the regular expression /^(\s*foo\s*)*$/ and Perl 5.6 and up immediately figures out that it doesn't match, while the others won't make significant progress in the projected lifetime of the Sun.

The two issues are connected: to keep the disaster expression from being a disaster, Perl keeps track of extra information during a match to avoid redoing the same work again and again. On most regular expressions this tracking takes a lot of work and buys you little to nothing. However every so often you aren't left wondering why your program unexpectedly froze.

In reply to Re: Interesting Perl/Java regexp benchmarking by tilly
in thread Interesting Perl/Java regexp benchmarking by dreadpiratepeter

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.