package MyClass;

use warnings;
use strict;
use diagnostics;

# If the first parameter is already an object of this
# class, simply return it, otherwise instanciate the
# new class and return the object.
# Upon error, returns undef.
sub _new_or_old
{
  my $invokant = shift;
  
  if( defined( $invokant ) )
  {
    if( ref( $invokant ) eq 'MyClass' )
    {
      return $invokant;
    }

    elsif( !ref( $invokant ) && ($invokant eq 'MyClass') )
    {
      my $self = {};
      bless( $self, $invokant );
      return $self;
    }
  }
  # If not defined $invokant, we *could* use a default.
  # As of now, we treat it as any other error.
  
  return undef;
}