some event. The special all-ones value means 'infinite'. May either
be printed as a decimal, eg, "3600", or as this name, eg, "infinite".
f - flag (true or false)
- A - array of whatever precedes (e.g., IA means array of IP addresses)
- a - array of the preceding character (e.g., IIa means two or more IP
- addresses)
+ A - array of all that precedes (e.g., fIA means array of records of
+ a flag and an IP address)
+ a - array of the preceding character (e.g., fIa means a single flag
+ followed by an array of IP addresses)
U - name of an option space (universe)
F - implicit flag - the presence of the option indicates that the
flag is true.