stack/stack.go
func (s *Signature) less(r *Signature) bool {
	if s.Stack.less(&r.Stack) {
		return true
	}
	if r.Stack.less(&s.Stack) {
		return false
	}
	if s.Locked && !r.Locked {
		return true
	}
	if r.Locked && !s.Locked {
		return false
	}
	if s.State < r.State {
		return true
	}
	if s.State > r.State {
		return false
	}
	return false
}
func (s *Signature) less(r *Signature) bool {
	if s.Stack.less(&r.Stack) {
		return true
	}
	if r.Stack.less(&s.Stack) {
		return false
	}
	if s.Locked && !r.Locked {
		return true
	}
	if r.Locked && !s.Locked {
		return false
	}
	if s.State < r.State {
		return true
	}
	if s.State > r.State {
		return false
	}
	return false
}
// less compares two Signature, where the ones that are less are more
// important, so they come up front. A Signature with more private functions is
// 'less' so it is at the top. Inversely, a Signature with only public
// functions is 'more' so it is at the bottom.