Switch / Case with multiple matches in same Case

ORQA
#1

Hello,

How does one match multiple possible Switch expression values in a single Case operation? Using OR (eg 2 || 3 ) results in that case being executed for all values (eg 2, 4, 9), while a comma isn’t accepted and trying =“2,3” doesn’t match either value.

Thanks,
James

#2

At the moment you would have to use ‘if’ operations to achieve that.

E.g. assuming the value you were using in your switch statement was in a variable called ‘value’ then something like the following work for your example:

if ^value == 2 || value == 3^ {
	// do something
} 
if ^value == 4^ {
	// do something else
}

In a classic switch statement to achieve that effect you would use blank cases without a break in them:

e.g.

switch value {
	case 2 {
	}
	case 3 {
		// do something
		break;
	}
	case 4 {
		// do something else
		break;
	} 
}

That behavior is called fallthrough. That behavior isn’t the default because it would require a lot of break statements adding clutter and most use cases don’t need it. It’s widely considered it was a mistake that fallthrough was the default in many standard languages. There’s a good discussion about it here: c - Why was the switch statement designed to need a break? - Stack Overflow

That said when we added the switch operations we did talk about adding the option to enable the fallthrough behavior as a parameter to the switch operation if it turned out people would need it.