dsl.pl

use strict;
use warnings;

use feature qw/say/;


our $_add = our $_remove = sub {
    say "add and remove should be called in builder block!";
};

sub add {
    $_add->();
}

sub remove {
    $_remove->();
}

sub builder(&) {
    local $_add = sub {
        say "add!";
    };
    local $_remove = sub {
        say "remove!";
    };

    shift->();
}

add();

builder {
    add();
}