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Control flow

All the statements, including the two details that surprise newcomers: switch falls through, and statements end at newlines.

1. Branches and loops

if (cond) { ... } else if (cond2) { ... } else { ... }

while (cond) { ... }

do { ... } while (cond)

for (init; cond; update) { ... }   // there is no for-in

break / continue / return [value]

Conditions must be bool; there are no truthy values. for is the C form only. There is no loop else, no labels, no goto.

2. switch

switch (x) {
    case 1:
        ...
        break
    case 2:
    case 3:            // fallthrough, like C
        ...
        break
    default:
        ...
}

• The value must be an integer type (byte, short, int, long); cases are integer literals.
• Fallthrough is intentional — forget break and execution continues into the next case.
• No case limit; nesting works.

3. Statement termination

Statements end at a newline. A semicolon also works, and newlines inside parentheses are ignored. The parser is lenient about adjacent statements (int x = 1 int y = 2 parses), but you should still write one statement per line.

4. FizzBuzz

%simple com.example.flow.FizzBuzz implements Main
    #import Std
    int run(int argc, String[] argv) Main@run {
        int i = 1
        while (i <= 15) {
            if (i % 15 == 0) {
                Std.print("FizzBuzz\n")
            } else if (i % 3 == 0) {
                Std.print("Fizz\n")
            } else if (i % 5 == 0) {
                Std.print("Buzz\n")
            } else {
                Std.print(i, "\n")
            }
            i = i + 1
        }
        return 0
    }

1
2
Fizz
4
Buzz
Fizz
7
8
Fizz
Buzz
11
Fizz
13
14
FizzBuzz

5. Fallthrough in practice

%simple com.example.flow.SwitchDemo implements Main
    #import Std
    int run(int argc, String[] argv) Main@run {
        int i = 0
        while (i < 4) {
            switch (i) {
                case 0:
                    Std.print("zero\n")
                    break
                case 1:
                case 2:
                    Std.print("one or two\n")
                    break
                default:
                    Std.print("many\n")
            }
            i = i + 1
        }
        return 0
    }

zero
one or two
one or two
many