you can do patterns like that with both component classes and composable functions, if that was what you were asking

You can show an example of how it can be done with functions?

Depends on what you’re wanting to do, but for instance a real naive version of the above could be done like the following

@Composable fun Scaffold(
  builder: ScaffoldScope.() -> Unit) {
  val scope = ScaffoldScope()
  scope.builder()
  // ... use `scope`
  scope.bodyComposable()
}
class ScaffoldScope(var bodyComposable: ...) {
  fun body(composable: @Composable() () -> Unit)  { bodyComposable = composable; }
}