for

The for statement initiates loop logic, allowing the iteration of a range of values.

The standard three-component FOR loop: for init?; condition?; post? { }

function main() {
    let list = [0, 10, 20]
    for (let i = 0; i < len(list); i++) {
        printf("index: %d:  value: %d", i, list[i])
        if (i == 5) {
            printf("break")
            break // break out of the current for loop
        } else {
            continue // skip the current iteration of the for loop
        }
    }
    return {}
}

Alternative for-each type loops:

for <index> <entry> = range <list> { }

for <key> <value> = range <map> { }

Note: The for ... range loop also supports utf8 encoded string. In this case, the index of the loop is the starting position of the current rune, as measured by bytes. See the example below:

function main() {
    let lst = [0, 10, 20]
    for i, v = range lst {
        printf("index: %d:  value: %d", i, v)
    }

    let map = {x:0, y:10, z:20}
    for k, v = range map {
        printf("key: %s:  value: %d", k, v)
    }

    // works for utf8 encoded strings
    let nihongo = "日本語"
    for i, s = range nihongo {
        printf("i:%d  s:%s", i, s)
    }
    // i:0  s:日
    // i:3  s:本
    // i:6  s:語
    return {}
}

Note: The range keyword in FOR loops are not part of the ES6 standards.

Break

Breaks out of the current FOR loop

function main() {
    ...
    if (i == 5) {
        printf("break")
        break // break out of the current for loop
    } else {
        continue // skip the current iteration of the for loop
    }
    ...
}

Continue

Skips the current iteration of the FOR loop