when / then / end — State-Tracked Loop

Syntax

when (condition) {
    // body — executes while condition is true
} then {
    // runs when loop completed normally (condition became false)
} end {
    // runs when condition was initially false, or break was used
}

Example

int32:i = 0i32;
int32:result = 0i32;
when (i < 3i32) {
    i = i + 1i32;
} then {
    result = 1i32;     // loop completed normally
} end {
    result = 2i32;     // condition was initially false or break
}

vs while

when/then/end is semantically similar to while but also tracks how the loop terminated. then runs on normal completion (condition became false). end runs if the condition was initially false or break was used. Use while for simple loops, when for state-driven loops where termination reason matters.

Notes

• The loop body goes in the when (cond) { } block
• then { } is the normal-completion handler
• end { } is the false-or-break handler

Related

• while.md — simple condition loops
• loop_till.md — counted iteration