I prefer to do something as such: 
use Scalar::Util qw( blessed );

sub new {
    my $class = shift;

    return $class->clone( @_ ) if blessed $class;

    # Continue on with constructor.
}

sub clone {
    my $self = shift;

    return $self->new( @_ ) unless blessed $self;

    # Continue on with cloner.
}

[download]

Otherwise, I document what my methods expect and laugh at the people who don't RTFM.

My criteria for good software:
  1. Does it work?
  2. Can someone else come in, make a change, and be reasonably certain no bugs were introduced?

In reply to Re: Objects and references by dragonchild
in thread Objects and references by jeanluca

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