Logical union (or)
The or operator produces a result of true if either of its operand values is true and false otherwise.
When the correlator evaluates a logical or expression, it evaluates the left operand first. If the left operand evaluates to true, then the correlator does not evaluate the right operand since the expression will always be true. For example:
a or b
If a is true, then regardless of what b evaluates to, the expression will be true so the correlator does not evaluate b.