Control Flow

Choosing: `if` / `else`

The part inside ( ) must be true or false. When it is true the first block runs; otherwise the else block:

age = ask("How old are you?")
if (age >= 10) {
    print("Wow, you are big!")
} else {
    print("You are small, but mighty!")
}

Chains work the way you expect:

if (guess < secret) {
    print("Too small!")
} else if (guess > secret) {
    print("Too big!")
} else {
    print("You got it!")
}

Repeating a fixed number of times: `repeat`

repeat takes a number and runs the block that many times:

repeat 4 {
    forward(100)
    turn_right(90)
}

Giving repeat something that is not a number is error E110.

Repeating while true: `while`

while keeps going as long as its condition is true:

make number = 5
while (number > 0) {
    print(number)
    number = number - 1
}
print("Liftoff!")

In the browser, endless loops can never freeze the page — the runtime yields regularly and the Stop button always works.

Leaving a loop: `stop`

stop breaks out of the current loop immediately:

i = 3
while (i > 0) {
    print(i)
    i = i - 1
    if (i == 1) { stop }
}

Using stop outside a loop is error E107.