Control Flow

if / else

if is an expression:

let label = if score >= 60 {
    "pass"
} else {
    "fail"
}

The condition must evaluate to Bool.

while

let n = 0

while n < 5 {
    print(n)
    n += 1
}

for

for consumes an iterable directly:

for x in [1, 2, 3] {
    print(x)
}

Ranges and strings work too:

for x in (1..5) {
    print(x)
}

for ch in "Novum" {
    print(ch)
}

break and continue

for x in (0..10) {
    if x == 5 {
        break
    }
    print(x)
}

for x in (0..10) {
    if x % 2 != 0 {
        continue
    }
    print(x)
}

return

Use return for an early function result:

absolute = |x| {
    if x < 0 {
        return -x
    }
    x
}

Ranges

Exclusive range:

1..5

Iterates as 1, 2, 3, 4.

Inclusive range:

1..=5

Iterates as 1, 2, 3, 4, 5.

Ranges are particularly useful with for, iter, and iterator pipelines.