Update WebIDL definition(s) to use new mixin syntax

[tobie]

Hi all!

WebIDL recently introduced dedicated syntax for mixins.

This syntax replaces the [NoInterfaceObject] extended attribute and implements statement which have been deprecated (except for a few legacy uses cases explicitely mentioned in the spec).

You can read more about it here.

In most cases, the changes should be relatively straightforward. The now deprecated:

interface Foo { };

[NoInterfaceObject]  // (Mostly) DEPRECATED
interface Bar { };
Foo implementes Bar; // DEPRECATED

should just be rewritten as:

interface Foo { };

interface mixin Bar { };
Foo includes Bar;

Additonaly, a section on when to use partials and mixins has been added to the spec. It's short and might be worth a read.

It seems the following interfaces in the Scalable Vector Graphics (SVG) 2 spec are impacted by this change:

• SVGTests
• SVGFitToViewBox
• SVGZoomAndPan
• SVGURIReference
• SVGElementInstance
• GetSVGDocument
• SVGAnimatedPoints

We're sorry for the inconvenience this causes, but our hope is that this ultimately makes things simpler and clearer for everybody.

As always, please feel free to reach out if you have any questions.

Thanks!

---

Tracked in: whatwg/webidl#472 | Original pull-request: whatwg/webidl#433

[dirkschulze]

@tobie What about GlobalEventHandlers? We implement it for SVGElement. Has it been updated yet?

[dirkschulze]

I also couldn't find an implement for GetSVGDocument. It is mentioned that it might be used in HTML by HTMLObjectElement with getSVGDocument. Was that updated already or is it going to be updated right after we change it in the spec?

[dirkschulze]

@tobie Other interfaces that we implement from HTML are:

• HTMLHyperlinkElementUtils
• WindowEventHandlers
• LinkStyle
• GlobalEventHandlers

We can only update those once HTML updated them.

[tobie]

Other interfaces that we implement from HTML are HTMLHyperlinkElementUtils, WindowEventHandlers, LinkStyle, and GlobalEventHandlers. We can only update those once HTML updated them.

HTML has been updated in whatwg/html#3207, so HTMLHyperlinkElementUtils, WindowEventHandlers, and GlobalEventHandlers have been converted to the new syntax.

LinkStyle, however, is defined in the CSSOM spec, which has not been converted yet. It's tracked here: w3c/csswg-drafts#1931.

[tobie]

I also couldn't find an implement for GetSVGDocument. It is mentioned that it might be used in HTML by HTMLObjectElement with getSVGDocument. Was that updated already or is it going to be updated right after we change it in the spec?

So the HTML spec defines the getSVGDocument operation rather than include the GetSVGDocument mixin. Looking at both definitions, it seems the HTML one is more specific.

There might be an opportunity here to simplify things, but that's a separate issue. GetSVGDocument really is a mixin regardless of whether other interfaces include it.

[dirkschulze]

@tobie Ok, replaced implements with includes for the HTML defined interfaces and made GetSVGDocument a mixin for now. We can discuss which spec should define the interface in a separate issue.

All that is left is the SVGPathSegment NoInterfaceObject of the SVG Path editors draft. This specs is not up for a WD as far as I know. Not sure if it even is on the charter of the SVG WG for this year. So there might be other changes to that spec anyway.