Control Flow

If/Else

if cond {
    ...
} else {
    ...
}

if requires a boolean condition and does not permit implicit truthiness.

Example:

if count > 0 {
    println("positive");
} else {
    println("zero");
}

While

while cond {
    ...
}

Example:

i32 mut i = 0;
while i < 3 {
    println(i);
    i = i + 1;
}

For (v0.1)

General form:

for item in expression {
    ...
}

Iterator contract

• expression must evaluate to an iterator-capable value.
• Iterator-capable means a resolvable Next() method returning Option<T>.
• Loop variable type is inferred from Option<T>::Some(T) item type.

Range compatibility fast-path

range(a, b) remains supported and keeps its existing behavior:

for i in range(0, 10) {
    ...
}

range(a, b) iterates from a (inclusive) to b (exclusive).

Lowering model

• Range expressions may lower through a dedicated numeric fast-path.
• General iterator form lowers to repeated Next() calls and loop termination on None.

Example:

i32 mut sum = 0;
for i in range(0, 4) {
    sum = sum + i;
}

Break/Continue/Return

break, continue, return behave as expected.

Example:

for i in range(0, 10) {
    if i == 3 { continue; }
    if i == 7 { break; }
}

i32 zero() {
    return 0;
}