First, you should understand bless. It makes a variable into an object, which just means that you can call the methods of whatever class you blessed it into via the object itself.

In example #2, the class that the object is being blessed into is whatever one the constructor physically appears in. That's the default. It's better to have the constructor get the class from the argument list and bless into it explicitly (like example #3), so that some derived class can call the same constructor and still get an object of the derived class.

Example #1 is too clever for its own good, and is frequently frowned upon as cargo-cult programming (see 408726). It takes the class or an object as an argument, then (if an object) gets the class type before doing the bless.

Caution: Contents may have been coded under pressure.

In reply to Re: confusion about blessing inside a constructor by Roy Johnson
in thread confusion about blessing inside a constructor by edwardt_tril

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.