zsoltk

@Composable
fun Content(backPress: Backpress) {
    // ...
}

zsoltk

@Composable
fun Content(backPress: Backpress) {
    var backStack by +state<BackStack<Routing>> { BackStack(Routing.AlbumList) }

    if (backPress.triggered) {
        backStack = backStack.pop()
        backPress.triggered = false
    }

    // remainder omitted

zsoltk

A [back stack of 1 element]
└── B [back stack of 2 elements]
      └── C [back stack of 4 elements]
            └── D [back stack of 1 element]
                  └── ...

zsoltk

A [back stack of 1 element]
└── B [back stack of 1 element]
      └── C [back stack of 1 element]
            └── D [back stack of 1 element]
                  └── ...

zsoltk

@Composable
fun SomeParent(backPress: Backpress, cantPopBackStack: () -> Unit) {
    var backStack by +state<BackStack<Routing>> { BackStack(Routing.Hello) }

    if (backPress.triggered) {
        if (!backStack.pop()) {
            cantPopBackStack()
        }
        backPress.triggered = false
    }

zsoltk

@Composable
fun Content(backPress: Backpress, cantPopBackStack: () -> Unit) {

    // remainder omitted
    
    SomeChild.Content(
        backPress = backPress
        // SomeChild’s fallback will be:
        cantPopBackStack = {
            // This is parent’s back stack

zsoltk

@Composable
fun Content(backPress: Backpress, cantPopBackStack: () -> Unit) {
    if (backPress.triggered) {
        cantPopBackStack()
    }
}

zsoltk

@Composable
fun Content(backPress: Backpress, cantPopBackStack: () -> Unit) {

    // remainder omitted

    SomeChild1.Content(
        backPress = backPress,
        cantPopBackStack = {
            if (!backStack.pop()) {
                cantPopBackStack()

zsoltk

@Composable
fun Content(backPress: Backpress, cantPopBackStack: () -> Unit) {

    // remainder omitted

    var unhandledCount = +memo { State(0) }
    val nbChildren = 2
    val cantPopBackStackDelegate = {
        // if we tried all of them and failed...
        if (++unhandledCount.value == nbChildren) {

zsoltk

A [Ambient provided with value: X]
└── B ...
      └── C ...
            └── D ...
                  └── E [Ambient read: X]