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Not, And, Or

boolean operators

Not E
E And F
E Or F

where E and F are of type BOOL.

These operators have their usual meanings. Note that when two or more boolean expressions are combined with AND, they are evaluated one by one until a FALSE expression is found. The rest are not evaluated. For example, given the expression A And B, the system does not attempt to evaluate B unless A evaluates to TRUE. Similarly, evaluation of a sequence of boolean expressions connected by OR stops as soon as a TRUE expression is found.