> On Apr 30, 2015, at 5:12 AM, Anne van Kesteren <ann...@annevk.nl> wrote: > > On Mon, Apr 27, 2015 at 11:05 PM, Ryosuke Niwa <rn...@apple.com> wrote: >>> The other thing I would like to explore is what an API would look like >>> that does the subclassing as well. >> >> For the slot approach, we can model the act of filling a slot as if >> attaching a shadow root to the slot and the slot content going into the >> shadow DOM for both content distribution and filling of slots by subclasses. >> >> Now we can do this in either of the following two strategies: >> 1. Superclass wants to see a list of slot contents from subclasses. >> 2. Each subclass "overrides" previous distribution done by superclass by >> inspecting insertion points in the shadow DOM and modifying them as needed. > > With the existence of closed shadow trees, it seems like you'd want to > allow for the superclass to not have to share its details with the > subclass.
Neither approach needs to expose internals of superclass' shadow DOM. In 1, what superclass seems is a list of proxies of slot contents subclasses provided. In 2, what subclass sees is a list of wrappers of overridable insertion points superclass defined. I can't think of an inheritance model in any programming language in which overridable pieces are unknown to subclasses. - R. Niwa