On Wed, May 6, 2015 at 2:05 AM, Anne van Kesteren <ann...@annevk.nl> wrote:
> It seems we have three contenders for the distribution API. > > 1) Synchronous, no flattening of <content>. A host element's shadow > tree has a set of slots each exposed as a single <content> element to > the outside. Host elements nested inside that shadow tree can only > reuse slots from the outermost host element. > > 2) Synchronous, flattening of <content>. Any host element nested > inside a shadow tree can get anything that is being distributed. > (Distributed <content> elements are unwrapped and not distributed > as-is.) > > 3) Lazy. A distinct global (similar to the isolated Shadow DOM story) > is responsible for distribution so it cannot observe when distribution > actually happens. > > The argument for 1 is that there are no (good?) use cases for 2 and > that descendants can be distributed, not just children. The argument > for 2 is that it can be used to implement <content select> and > <content slot> without much difficulty. The argument for 3 is that > distribution is a layout concept (despite also impacting non-UI events > and DOM APIs). > > (1/2 also require something akin "nanotask" mutation observers.) > > As I said elsewhere it's not clear to me we should couple DOM and > layout. The composed tree is distinct from the render tree. It's also > not clear to me what 3 would look like. No concrete proposal has been > made. What is clear to me given the experience with service workers is > that introducing a new global environment is not simple and would > likely set us back another couple of years. > > That leaves 1/2 and although Ryosuke and Tab have taken sides, neither > has really backed up their story. I tried to explore 1 in > https://lists.w3.org/Archives/Public/public-webapps/2015AprJun/0474.html > but that did not get much traction. So... trying again. > To complement this email, here's the in-depth (and work-in-progress) discussion of this: https://github.com/w3c/webcomponents/blob/gh-pages/proposals/Imperative-API-for-Node-Distribution-in-Shadow-DOM.md
