2.2.3.2.18 Expressions in DRM Licenses

An expression in a Digital Rights Management (DRM) license is a combination of operators and identifiers that specifies a computation of a value or that designates a variable or a constant.

The <CONDITION> element (when used under the <ONACTION>, <ONSELECT>, and <ONSTORE> elements) and the ACTION element of a license are expressions. An expression can consist of the following items: Identifier (section 2.2.3.2.18.1), Function Symbol (section 2.2.3.2.18.2), Constant (section 2.2.3.2.18.3), Variable (section 2.2.3.2.18.4), and Final Value (section 2.2.3.2.18.5).

If more than one statement is used within an expression, each statement must be terminated with a semicolon (;). The evaluation of the last statement in a semicolon-delimited list is treated as the result for the evaluation of that list of expressions. For example, in the expression "1+2;4", the first statement evaluates to the value of three and the second statement evaluates to the value of four. The entire expression then evaluates to the value of four.