You can use the following Boolean operators in any ACS routine:

This:

Means this:

AND or &&;

And

OR or |

Or

Expressions in parentheses are processed first. In the following example, the set of OR expressions are processed first, so that

WHEN ((CONDITION 1) OR
      (CONDITION 2) OR
      (CONDITION 3) AND
      (CONDITION 4)) SET ...

is processed as follows:

WHEN
 (CONDITION 1 AND CONDITION 4) OR
 (CONDITION 2 AND CONDITION 4) OR
 (CONDITION 3 AND CONDITION 4) SET ...

If you want the AND expression be processed before OR, the AND expression must be included in a set of parentheses. In the following example, AND is processed first so that

WHEN ((CONDITION 1) OR
       (CONDITION 2) OR
       ((CONDITION 3) AND
       (CONDITION 4))) SET...

is processed as follows:

WHEN ((CONDITION 1) OR
      (CONDITION 2) OR
      (CONDITION 3 AND CONDITION 4)) SET...