If

if can be used as statement. The difference from if expression is that statements are placed in {}.

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

    always_comb {
        if a == 0 {
            b = 1;
        } else if a >: 1 {
            b = 2;
        } else {
            b = 3;
        }
    }
}