Another conditional expression is case. case containts some arms like expression: expression. If the expression after case keyword matches the left expression of an arm, the right expression of the arm will be returned. default is a special arm which will be returned when all other arms are failed. default is mandatory because if expression always have to be evaluated to value.

module ModuleA {
    let a: logic<10> = 1;
    var b: logic<10>;
    let c: logic<10> = 1;

    assign b = case a {
        0      : 1,
        1      : 2,
        c - 1  : 4,
        default: 5,