REPEAT..UNTIL Loop

The while loop checks its condition before each iteration. If the condition is false from the start, the body never runs at all. Sometimes that’s not what you want — you need the body to execute at least once, and only then decide whether to keep going.

The repeat..until loop does exactly that. It runs the body first, then checks the condition. If the condition is true, the loop stops. If it’s false, the loop repeats.

Syntax

repeat
    <body>
until <condition>

Compare this with while:

	Checks condition	Guaranteed to run at least once?
`while`	Before each iteration	No
`repeat..until`	After each iteration	Yes

Example

Here is a simple repeat..until loop that waits for the player to press F5:

repeat
    wait 0
until is_key_pressed 116

The wait 0 always executes at least once, giving the game a chance to process input before the first check. Compare it with the equivalent while version:

while not is_key_pressed 116
    wait 0
end

Both achieve the same result, but notice how the condition is inverted: while needs not is_key_pressed (keep going while the key is not pressed), whereas repeat..until uses is_key_pressed directly (stop when the key is pressed).

Practical Example

This script counts how many seconds the player waits before pressing F5:

int seconds = 0

repeat
    wait 1000
    seconds += 1
    print_formatted_now "Waiting... %d seconds" 1000 seconds
until is_key_pressed 116

print_formatted_now "You waited %d seconds!" 3000 seconds

Because repeat..until always runs the body first, the counter starts at 1 even if the player presses F5 immediately.