That's a very confusing example because it looks like an object but isn't. That example would still work if you remove the OO looking stuff: 
#!/usr/local/bin/perl
use strict;

my $dave = subref("dave", "oranges", "grapefruit");
$dave->("debug message");

sub subref {
        my (@stuff) = @_;
        return sub { doit(@stuff, @_) }; # <-- closure here?
}

sub doit {
        print shift, ": ", join(",", @_), "\n";
}

[download]
Yes, it is a closure, but it's also an anonymous sub ref, so it's showing multiple things. Here's a much simpler closure: 
my $foo;

sub bar {
    $foo++;
}

[download]
After execution, bar() has a private copy of $foo. TheDamian uses this in his book to do private variables for classes.

In reply to Re: Why are closures cool, continued? by perrin
in thread Why are closures cool, continued? by mr.dunstan

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.