=over =item __SUB__ X<__sub__> A special token that returns a reference to the current subroutine, or L|/undef EXPR> outside of a subroutine. The behaviour of L|/__SUB__> within a regex code block (such as C(?{...})/>) is subject to change. This token is only available under C or the L feature|feature/The 'current_sub' feature>. See L. =back