set Assignment Statement with Boolean Expressions

Syntax	`set aBoolean = <boolean expression>;`
Semantics	Evaluates `<boolean expression>` to true or false and assigns the boolean value to `aBoolean`. Boolean variables can be used in boolean expressions.
Examples	`set b1 = b2 and b3; set b4 = b2 or b3; set b5 = b2 and (b3 or b4); set b6 = not (b2); set b7 = 2 < 1;`