Switch case with multiple values for the same case

Question

I would like to know the syntax to set a multiple case statement in a switch / case.
For example :

String commentMark(int mark) {
    switch (mark) {
        case 0 : // Enter this block if mark == 0
            return "Well that's bad" ;
        case 1, 2, 3 : // Enter this block if mark == 1 or mark == 2 or mark == 3
            return "Gods what happend" ;
        // etc.
        default :
            return "At least you tried" ;
    }
}

I cannot find the right syntax to set multiple case (the line case 1, 2, 3 :), is it even possible in Dart ?

I did not found any informations on pub.dev documentation, neither on dart.dev.

I tried :
case 1, 2, 3
case (1, 2, 3)
case (1 ; 2 ; 3)
case (1 : 2 : 3)
case 1 : 3
and more !

Answer 1

Execution continues until it reaches a break;. Therefore, you can list cases one after the other to get the following code execute on either one of those cases.

String commentMark(int mark) {
    switch (mark) {
        case 0 : // Enter this block if mark == 0
            return "mark is 0" ;
        case 1:
        case 2:
        case 3: // Enter this block if mark == 1 or mark == 2 or mark == 3
            return "mark is either 1, 2 or 3" ;
        // etc.
        default :
            return "mark is not 0, 1, 2 or 3" ;
    }
}

The return statements above serve to get out of the function. If you do not want to return, you have to use break; after each block, of course. This code below is equivalent to the one above.

String commentMark(int mark) {
    String msg;
    switch (mark) {
        case 0 : // Enter this block if mark == 0
            msg = "mark is 0" ;
            break;
        case 1:
        case 2:
        case 3: // Enter this block if mark == 1 or mark == 2 or mark == 3
            msg = "mark is either 1, 2 or 3" ;
            break;
        // etc.
        default:
            msg = "mark is not 0, 1, 2 or 3" ;
            break; // this is a good habit, in case you change default to something else later.
    }
    return msg;
}

Answer 2

Instead of multiple case we can use or operator in single switch case it self.

switch (date) {
        case 1 | 21 | 31:
            return "st";
        case 2 | 22:
            return "nd";
        case 3 | 23:
            return "rd";
        default:
            return "th";
        }