Private methods in Perl5

It is common knowledge that you can’t have private functions and methods in Perl5. But it turns out that you can do it, one way is to use namespace::clean. Using this module you can either declare all the names of private functions at the top or use a serie of non-obvious “use namespace::clean“, “no namespace::clean” calls.

Wouldn’t it be much nicer just to be able to write:

sub foo :Private {
    ...
}

You can, with my brand new Sub::Private module. It is actually quite simple:

use Attribute::Handlers;

use namespace::clean     qw();
use B::Hooks::EndOfScope qw(on_scope_end);
use Sub::Identify        qw(get_code_info);

sub UNIVERSAL::Private :ATTR(CODE,BEGIN) {
    my ($package, $symbol, $referent, $attr, $data) = @_;

    on_scope_end {
        namespace::clean->clean_subroutines( get_code_info( $referent ) );
    }
}

Putting the attribute handler in the UNIVERSAL namespace isn’t nice. I have to find a solution for that for the next version.