Re: about perltoot

[Mumia W.]

On 09/21/2006 07:08 PM, chen li wrote:
Hi all,
I read some sections in perltoot. In section
Autoloaded Data Methods I see some line codes as
following:

 package Person;
        use Carp;
        our $AUTOLOAD;  # it's a package global

        my %fields = (
            name        => undef,
            age         => undef,
            peers       => undef,
        );

        sub new {
            my $class = shift;
            my $self  = {
                _permitted => \%fields,
                %fields,
            };
            bless $self, $class;
            return $self;
        }

It looks like that  _permitted => \%fields and %fields
are redundant. [...]

That "redundancy" allows you to use inheritance. If you have a class 
Employee, with an expanded set of fields, this method makes it possible 
to add the fields without having to modify each method that uses them.




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