Dear monks,

I have a question about the '=' operator :-)

I caught myself doing the following: 
sub path_to_root {
    my $self = shift;
    my $path = $self->get_branch_length;
    while ( $self ) {
        if ( $self->get_parent ) {
            $self = $self->get_parent;
            $path += $self->get_branch_length;
        }
        else {
            return $path;
        }
    }
}

[download]
That is to say, I make the $self->get_parent method call twice, once to check if there really is a parent, the second time to step to that parent during my traversal (here we're traversing a tree from initial node $self to the root, but this issue is more broadly applicable, obviously).

So if we do an assignment, what value is returned that I can test? Is it the left hand value - i.e. would the following be equivalent, but more efficient? 
sub path_to_root {
    my $self = shift;
    my $path = $self->get_branch_length;
    while ( $self ) {
        if ( $self = $self->get_parent ) {
            $path += $self->get_branch_length;
        }
        else {
            return $path;
        }
    }
}

[download]

In reply to assignment operator return values by rvosa

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.