(:long-name @<string>) @! \\
(@<string> @<format-arg>^+) @!
(:doc @<string> @<format-arg>^*) @! \\
- (:opt-arg @<arg-name>) @! \\
+ (:arg @<arg-name>) @! (:opt-arg @<arg-name>) @! \\
@<keyword> @! (:tag @<tag>) @!
(:negated-tag @<tag>) @! \\
@{ (@<handler> @<var> @<handler-arg>^*) @}^*