Variable
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;
}