Switch Statements

Switch statements in Spice can be used to execute different code paths based on the value of a variable. This is similar to switch statements in other languages, but with some differences. The expression in the switch statement can be of type int, long, short, byte, char or bool and the individual match expressions need to be literals of the respective type.

Usage¶

Here's a simple example for an switch statement:

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switch number {
    case 0: { printf("Zero"); }
    case 1: { printf("One"); }
    case 2: { printf("Two"); }
    case 3: { printf("Three"); }
    case 4: { printf("Four"); }
    case 5: { printf("Five"); }
    case 6: { printf("Six"); }
    case 7: { printf("Seven"); }
    case 8: { printf("Eight"); }
    case 9: { printf("Nine"); }
    default: { printf("NaN"); }
}

Let's take a look at a switch statement:

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switch (input) {
    case 0, 2, 4, 6, 8: { printf("Even"); }
    case 1, 3, 5, 7, 9: { printf("Odd"); }
}

Fallthrough¶

In Spice, the switch statement does not fall through by default. This means, that you don't need to use the break keyword to prevent the next case from being executed, like in other languages. In Spice, you have to use the fallthrough keyword to fall through to the next case branch. This originated from the assumption, that you more often want to execute one branch, instead of having fallthrough behavior.

The fallthrough keyword can be used like this:

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int i = 1;
switch i {
    case 1, 2: {
        printf("1 or 2\n");
        fallthrough;
    }
    case 6, 9: {
        printf("6 or 9\n");
    }
    default: {
        printf("Default\n");
    }
}