Q&A

Q1:Can I put functions in my class, and call them directly without an object?
A1: Yes. In object-oriented terminology these are called class methods. To call a subroutine named doit (and retrieve its value) in a class named Widget you can do any of the following: 
$value = Widget->doit();
$value = Widget::doit();
$value = doit Car;

The last one may look odd, but it's a piece of syntax sugar that means the same thing as the others.

Q2:This hour missed a lot of object-oriented stuff. There was no inheritance! No polymorphism!
A2: There's far, far too much to cover in an hour. Perl includes these manual pages dedicated to objects: perlboot, perltoot, perltootc, perlobj, and perlbot. For an entire book on Perl objects, I'd recommend Object Oriented Perl by Damian Conway.
Q3:If my object has lots and lots of properties, how can I access them if I don't want to create a function for each one of them?
Q4:If you call a method on an object, and that method doesn't exist in the class, Perl looks for a subroutine named AUTOLOAD and calls that instead. The first argument will be the object, the remaining arguments will be passed as well, and a special variable called $AUTOLOAD will be set to the class::method name you were trying to access. Here's a simple autoloader that could be used to implement a new method called filename in your TYPFileInfoOO class.
our($AUTOLOAD);  # This goes near the top of the class
sub AUTOLOAD {   # This can go anywhere
    my($self, $value)=@_;
    my($property)=($AUTOLOAD=~m/::(.*?)$/);
    die "No property $property" unless exists $self->{$property};
    if (defined $value) {
        return $self->{$property}=$value;
    } else {
        return $self->{$property}
    }
}

If a property does not exist inside of $self, the AUTOLOAD subroutine dies. If it does, the property value is changed to $value if $value is defined; otherwise it's returned.

If you add more key/value pairs to the hash, this AUTOLOAD will give you access to them as properties.

..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.
Reset
18.217.249.77