references; see L<attributes> and L<Attribute::Handlers> for more
information about attributes.
-=item substr EXPR,OFFSET,LENGTH,REPLACEMENT
-X<substr> X<substring> X<mid> X<left> X<right>
-
=item __SUB__
X<__SUB__>
This token is only available under C<use v5.16> or the "current_sub"
feature. See L<feature>.
+=item substr EXPR,OFFSET,LENGTH,REPLACEMENT
+X<substr> X<substring> X<mid> X<left> X<right>
+
=item substr EXPR,OFFSET,LENGTH
=item substr EXPR,OFFSET