Perl object-orientation isn't OO. Well, it is. You can create objects (known as modules), tell them what they are (by blessing them), and create method inheritance (through @ISA). From a very nuts'n'bolts view, that's basically all you need for functional OO. Encapsulation and Inheritance. Data inheritance is often nice to have, too. But, that's easily done by being intelligent in your initialization function(s).

However, I have to vehemently disagree with the concept of using AUTOLOAD to do everything. Frankly, that's unmaintainable in the long run. (Not to mention being a little slower than previously-declared functions.) Here is a basic OO design I am currently using in a medium application and it works beautifully:

sub get_attribute_names_and_defaults {
    my $pkg = shift;
    $pkg = ref($pkg) if ref($pkg);

    my @result = @{"${pkg}::_ATTRIBUTES_"};
    if (defined @{"${pkg}::ISA"}) {
        push @result, get_attribute_names_and_defaults($_) for @{"${pk
+g}::ISA"};
    }

    @result;
}

sub define_attributes {
    my $self = caller;
    my $pkg = ref($self) ? ref($self) : $self;

    my $pkg_string = "${pkg}::_ATTRIBUTES_";
    if (defined @{$pkg_string}) {
        push @{$pkg_string}, @_;
    } else {
        @{$pkg_string} = @_;
    }
}

sub new {
    my $type = shift;
    my %args = @_;

    my $self = {};
    bless $self, $type;

    my $attr_name;
    my $pkg = ref($self);
    my %defaults = Global::Generic_Object::get_attribute_names_and_def
+aults($pkg
);
    for (keys %defaults) {
        $attr_name = Global::Generic_Object::_input_to_attribute(undef
+, $_);
        unless (exists $self->{$attr_name}) {
            my $default_ref = ref($defaults{$_});
            if ($default_ref eq 'ARRAY') {
                if (@{$defaults{$_}}) {
                    $self->{$attr_name} = [ @{$defaults{$_}} ];
                } else {
                    $self->{$attr_name} = [];
                }
            } elsif ($default_ref eq 'HASH') {
                if (@{$defaults{$_}}) {
                    $self->{$attr_name} = { %{$defaults{$_}} };
                } else {
                    $self->{$attr_name} = {};
                }
#            } elsif ($default_ref eq 'SCALAR') {
#                $self->{$attr_name} = \$$defaults{$_};
#            } elsif ($default_ref) {
            } else {
                $self->{$attr_name} = $defaults{$_};
            }
        }
    }

    $self->_initialize(%object_hash, %args);

    return $self;
}

define_attributes(-REGISTERED_NAME => '');

sub _initialize {
    my $self = shift;

    $self->set(@_);

    return 1;
}

sub exists {
    my $self = shift;
    my @args = @_;

    my @return_list = ();
    foreach my $in (@args) {
        my ($obj, $data) = split (/\./, $in, 2);
        my $key = $self->_input_to_attribute($obj);

        if (exists $self->{$key}) {
            if ($data && ref $self->{$key} && ref($self->{$key}) =~ /:
+:/) {
                push @return_list, $self->{$key}->exists("-$data");
            } else {
                push @return_list, 1;
            }
        } else {
            push @return_list, 0;
        }
    }

    return @return_list == 1 ? $return_list[0] : @return_list;
}

[download]

get(), set(), inc(), strcat(), and clr() all are defined in the same way. You have one function that handle attribute retrieval. That's it. Nothing more. Plus, this handles attribute inheritance as well.

Thoughts?

In reply to Re: Perl and Objects, how do you resolve the two? by satchboost
in thread Perl and Objects, how do you resolve the two? by frankus

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