- (opt-string MSG [RO [PRED]])syntax
opt-body element for string values.
- MSG
- (or string (string *)) ; message, * is default value
- RO
- (or (required KIND) (optional KIND) KIND) ; requirement
- PRED
- (string -> boolean) ; predicate
(et ,@(opt-string "entry thingy directory" ET-PATHNAME dirname?))