I don't think defining a slot based on an attribute value is something we'd like to support.
> On Apr 22, 2015, at 10:21 AM, Justin Fagnani <justinfagn...@google.com> wrote: > > Another technique I've seen used is compound selectors, which could be used > to migrate from one selector to another while preserving backwards > compatibility, or to provide some nice default distributions that are also > accessible via a class or attribute (ie, select="header, .header"). > > Could slots have multiple names to support something like this? > > On Wed, Apr 22, 2015 at 10:16 AM, Justin Fagnani <justinfagn...@google.com > <mailto:justinfagn...@google.com>> wrote: > > > On Tue, Apr 21, 2015 at 10:40 PM, Ryosuke Niwa <rn...@apple.com > <mailto:rn...@apple.com>> wrote: > > > On Apr 21, 2015, at 10:23 PM, Justin Fagnani <justinfagn...@google.com > > <mailto:justinfagn...@google.com>> wrote: > > > > I do want the ability to redirect distributed nodes into a holes in the > > base template, so that part is welcome to me. However, my first reaction to > > the slot idea is that forcing users to add the content-slot attribute on > > children significantly impairs the DOM API surface area of custom elements. > > > > For the single-level distribution case, how is this different from <content > > select="[content-slot=name]"> except that content select can distribute > > based on features of the children that might already exist, like tag names > > or an attribute? > > At the conceptual level, they're equivalent. However, we didn't find the > extra flexibility of using CSS selectors compelling as we mentioned in our > proposal . > > I personally would like to see more power, especially positional selectors. > Some components would be better off selecting their first child, rather than > requiring a class. > >  See points 3 and 4 in > https://github.com/w3c/webcomponents/wiki/Proposal-for-changes-to-manage-Shadow-DOM-content-distribution#some-issues-with-the-current-shadow-dom-spec > > <https://github.com/w3c/webcomponents/wiki/Proposal-for-changes-to-manage-Shadow-DOM-content-distribution#some-issues-with-the-current-shadow-dom-spec> > > Point 4 is interesting, because unless I'm missing something (which could > be!) it's incorrect. You can create selectors with :not() that exclude the > content selectors that come after in document order. I would rewrite the > example as: > > <template> > <content select=".header"></content> > <content select=":not(.footer)"></content> > <content select=".footer"></content> > </template> > Cheers, > Justin > > > > - R. Niwa > > >