    <rule_decl>
        { return $_[0]{rule_decl}->();
        }
    |
    <sub_decl>
        { return $_[0]{sub_decl}->();
        }

    ( multi | <''> ) <?ws>?
    ( rule | regex | token ) <?ws>?

    ( my | <''> ) <?ws>?
    ( multi | <''> ) <?ws>?
    ( submethod | method | sub ) <?ws>?