I wasn't going to continue the N/3 subject scheme but since the preceding five haven't yet been pushed to git origin I couldn't think of a better way to indicate that they have to be applied in sequence. This patch covers the discussion with Oliver Kiddle from the [PATCH 1/3] thread. * Add "unset -n" * Allow and enforce "typeset -n -r" for read-only references * "can't change type via subscript reference" error * Better checking for self-referential declarations/assignments * Ksh-style "foo=bar; typeset -n foo" creates foo=bar reference * Support "typeset -n ref; for ref in ..." * Subscripted references use NO_EXEC for safety * References assigned in called scopes reset scope at end * Allow named references to $! $? $$ $- $0 $_