Function Stack

debug.go:193–204

Stack gets information about the interpreter runtime stack. It returns a Frame identifying the activation record of the function executing at a given level. Level 0 is the current running function, whereas level n+1 is the function that has called level n (except for tail calls, which do not count

(l *State, level int)

// Stack returns true; when called with a level greater than the stack depth,
// it returns false.
func Stack(l *State, level int) (f Frame, ok bool) {
	if level < 0 {
		return // invalid (negative) level
	}
	callInfo := l.callInfo
	for ; level > 0 && callInfo != &l.baseCallInfo; level, callInfo = level-1, callInfo.previous {
	}
	if level == 0 && callInfo != &l.baseCallInfo { // level found?
		f, ok = callInfo, true
	}
	return
}

func functionInfo(p Debug, f closure) (d Debug) {
	d = p