Clément Pit-Claudel <cpitclaudel@gmail.com> schrieb am So., 2. Juli 2017 um
19:26 Uhr:

> On 2017-07-02 12:54, Noam Postavsky wrote:
> > On Sun, Jul 2, 2017 at 12:32 PM, Clément Pit-Claudel
> > <cpitclaudel@gmail.com> wrote:
> >>> Why would we need a new function since %n$ would be an error for the
> old format anyway?
> >>
> >> This in itself is a good reason to have a new function.  A new function
> lets you migrate existing code, including plugins, to the new syntax, and
> load the polyfill in older Emacsen.  A new syntax that causes errors in old
> Emacsen isn't usable by anyone outside of Emacs core, for fear of
> compatibility problems.
> >
> > We can still give a new name I suppose.
>
> I think it would be nice, if we also write a polyfill. If we don't intend
> to write one, then there's probably no point.
>

We can't write a polyfill, just like browser developers can't write
polyfills (if they do so, it's just normal functionality).
Third-party library authors can write polyfills, of course, if they want.