Scope chain rules

Scopes cascade up the DOM tree. VSN resolves values and assignments using a predictable order.

Lookup order

1) local scope
2) parent scope
3) root scope

If a variable exists up the chain, assignments update the nearest scope that has it.
If it doesn’t exist, the variable is created locally.
Use self. to force a local variable.
Use parent. or root. to be explicit.

behavior .list {
  count: 0;

  behavior .item {
    on click() { count += 1; }
    on dblclick() { self.count = 100; }
  }
}

Single clicks update the list count. Double clicks create a local count on the item.