Re: Private methods

[adrianh]

in reply to Private methods

If you want to create a subroutine that only the Foo package can access, lexically scoped coderefs are the way to go. However, I can only think of a few situations where you really need to be that secretive.

I find that most of the time all I need is to prevent a subclass overriding the subroutine, in which case I would either calling it as a subroutine rather than a method, or specify the package of the method directly. For example:

package Foo;

sub _init { shift->{foo} = 1 }

sub new {
    my $class = shift;
    my $self = bless {}, $class;
    _init($self);
    $self;
}

package Bar;
use base qw(Foo);

sub _init { shift->{bar} = 2 }

sub new {
    my $class = shift;
    my $self = $class->SUPER::new;
    _init($self);
    $self;
}

or

package Foo;

sub _init { shift->{foo} = 1 }

sub new {
    my $class = shift;
    my $self = bless {}, $class;
    $self->Foo::_init;
    $self;
}

package Bar;
use base qw(Foo);

sub _init { shift->{bar} = 2 }

sub new {
    my $class = shift;
    my $self = $class->SUPER::new;
    $self->Bar::_init;
    $self;
}

gives us

package main;
use Data::Dumper;
print Dumper(Bar->new);

__END__
$VAR1 = bless( {
                 'bar' => 2,
                 'foo' => 1
               }, 'Bar' );

[adrianh]

... and after Apocalypse 6 we have submethods & BUILD in perl 6:

... in Foo ...

submethod BUILD { $.foo = 1 };

... in Bar ...

submethod BUILD { $.bar = 2 };

I so want perl6 now :-)