Variable declaration is started by var keyword. After var, variable name, :, and the type of the variable are followed.

If there are unused variables, warning will be occured. Variable name starting with _ means unused variable, and suppresses the warning.

If you want to bind a value to a name at the declaration, let can be used instead of var.

module ModuleA {
    var _a: logic        ;
    var _b: logic<10>    ;
    var _c: logic<10, 10>;
    var _d: u32          ;
    let _e: logic         = 1;

    assign _a = 1;
    assign _b = 1;
    assign _c = 1;
    assign _d = 1;