In Damian Conway's "Abbot and Costello Who's on First'" Parse::RecDescent example code in "Computer Science & Perl Programming" he starts the code with the line

use vars qw( %base %man @try_again);

and then in the action blocks in the grammars uses those variables with the syntax, e.g., $::man{$item[4]} and @::try_again.

As I thought the point of the 'use vars' pragma was to allow the variables to be used globally without writing the fully qualified name, I'm puzzled as to why the double colons are used.

In reply to What does '::' mean in constructs '$::foo' and '@::foo'? by jmeek

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.