> On Apr 30, 2015, at 4:43 AM, Anne van Kesteren <ann...@annevk.nl> wrote:
> On Tue, Apr 28, 2015 at 7:09 PM, Ryosuke Niwa <rn...@apple.com> wrote:
>> The problem with "<shadow> as function" is that the superclass implicitly 
>> selects nodes based on a CSS selector so unless the nodes a subclass wants 
>> to insert matches exactly what the author of superclass considered, the 
>> subclass won't be able to override it. e.g. if the superclass had an 
>> insertion point with select="input.foo", then it's not possible for a 
>> subclass to then override it with, for example, an input element wrapped in 
>> a span.
> So what if we flipped this as well and came up with an imperative API
> for "<shadow> as a function". I.e. "<shadow> as an actual function"?
> Would that give us agreement?

We object on the basis that "<shadow> as a function" is fundamentally backwards 
way of doing the inheritance.  If you have a MyMapView and define a subclass 
MyScrollableMapView to make it scrollable, then MyScrollableMapView must be a 
MyMapView.  It doesn't make any sense for MyScrollableMapView, for example, to 
be a ScrollView that then contains MyMapView.  That's has-a relationship which 
is appropriate for composition.

- R. Niwa

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