Yes yes, we all remember the node about "ig" and "ds" and "di" being legacy Perl 4 things... 
/* from op.c */

if (ckWARN(WARN_VOID)) {
  useless = "a constant";  
  /* the constants 0 and 1 are permitted as they are
     conventionally used as dummies in constructs like
     1 while some_condition_with_side_effects;  */  
  if (SvNIOK(sv) && (SvNV(sv) == 0.0 || SvNV(sv) == 1.0))
    useless = 0;
  else if (SvPOK(sv)) {
    /* perl4's way of mixing documentation and code
       (before the invention of POD) was based on a
       trick to mix nroff and perl code. The trick was
       built upon these three nroff macros being used in
       void context. The pink camel has the details in   
       the script wrapman near page 319. */
    if (strnEQ(SvPVX(sv), "di", 2) ||
        strnEQ(SvPVX(sv), "ds", 2) ||
        strnEQ(SvPVX(sv), "ig", 2))
          useless = 0;
  }
}

[download]


japhy -- Perl and Regex Hacker

In reply to Re: (tye)Re: Regular expression by japhy
in thread Regular expression by nysus

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.