Control flow

Zap keeps control flow explicit. Conditions always use Bool, blocks use braces, and loops make their iteration rule visible.

Conditions

Use if when a branch depends on a boolean expression.

if ready {
    println("start");
} else {
    println("wait");
}

Repetition

Use while when a condition controls each iteration:

while remaining > 0 {
    remaining = remaining - 1;
}

Use for for a counted loop or iteration over an array, slice, or collection:

for var index: Int = 0; index < 3; index = index + 1 {
    println(toString(index));
}

break leaves the nearest loop and continue starts its next iteration.

Block scope

Names declared inside a branch or loop are not visible after that block:

if enabled {
    var message = "on";
    println(message);
}

// `message` is not available here.

Start with if when learning the individual forms.