;/2 -- disjunction+*P ; +*Q
Disjunction: Succeeds if P succeeds or Q succeeds.
This is normally regarded as part of the
syntax of the language, but it is like a built-in predicate in that
you can say call (P ; Q). The character |
(vertical bar) can be used as an alternative to ;.
Note that ;/2 has a distinct behaviour if the first argument
is a ->/2 term. See ;/2 - if-then-else.