A combined condition results from connecting conditions with one of the logical operators AND or OR. The general format is:
condition { {AND} condition } ...
{OR }
In the general format, condition may be any of the following:
1. a simple condition
2. a negated simple condition
3. a combined condition
4. a negated combined condition; that is, a "NOT" followed by a combined condition enclosed in parentheses
Parentheses may be used in a complex condition to alter the rules of evaluation. Parentheses must be made in matched pairs and must be placed in such a way so that the enclosed symbols constitute a well-defined condition.
The truth value of a combined condition using AND is true only when both component conditions are true. The truth value of a combined condition using OR is true when either or both of the component conditions are true.