This does involve us losing the type argument present in the WebIDL, but for now
that should be fine as we're exposing low-level bindings and it's not otherwise
clear whether having a typed wrapper is a great option. Usage of `JsCast` can
convert the incoming value to a different object fairly easily.
The purpose of the `web-sys` crate is to expose functionality of the web, not
necessarily take an opinionated stance on how it should be exposed. In that
sense it should be able to work with the `Promise` as you would a typed promise
in terms of no functionality is left out. That being said we'll likely want to
be sure to reconsider this before 1.0-stabilizing the `web-sys` crate!
This commit adds support for two different features of the "special" operations
in WebIDL. First, it implements the desugaring [described by WebIDL][1] where
this:
interface Dictionary {
getter double getProperty(DOMString propertyName);
setter void setProperty(DOMString propertyName, double propertyValue);
};
becomes ...
interface Dictionary {
double getProperty(DOMString propertyName);
void setProperty(DOMString propertyName, double propertyValue);
getter double (DOMString propertyName);
setter void (DOMString propertyName, double propertyValue);
};
where specifically a named `getter` generates both a getter and a named
function.
Second it implements the distinction between two different types of getters in
WebIDL, described as:
> Getters and setters come in two varieties: ones that take a DOMString as a
> property name, known as named property getters and named property setters, and
> ones that take an unsigned long as a property index, known as indexed property
> getters and indexed property setters.
The name `get` is given to DOMString arguments, and the name `get_idx` is given
to index property getters.
[1]: https://heycam.github.io/webidl/#idl-special-operations
