Re: PL support

[Fu Yuan]

> 在 2020年5月10日，下午11:56，Stefan Monnier <address@hidden> 写道：
> 
> Richard wrote:
>> Some contributors are eagerly planning a sort of automatic facility to
>> "install external tools."  I'm disappointed to have to say that this
>> raises problems at various levels.  I doubt there is an acceptable way
>> to do it.
> 
> There is no doubt that acceptable ways to do it exist.
> 
> As a matter of fact, we *already* do that, typically in the form of
> instructions in `Commentary:`, `INSTALL`, manuals, messages in
> mailing-lists, etc...
> 
> These instructions raise various problems, indeed.
> 
> Other ways to "do that" would solve some of those problems, preserve
> some of them, and introduce yet new ones.
> 
> There's a vast design space here, with many points in there which should
> be very much acceptable to our usually conservative sensitivity of
> "don't do anything without a very explicit user consent".
> 
> Daniel wrote:
>> You seem to be imagining a world in which Emacs installing external software
>> means that it runs distribution package manager tools or plops binaries in
>> /usr/bin. You can instead bundle known-good versions of external tools with
>> Emacs and run them in a controlled way from filesystem locations that Emacs
>> controls. Downloading revisions of these tools that hash to entries on an
>> Emacs whitelist is equivalent.
> 
> FWIW, I probably wouldn't like a solution where we bundle binaries of
> external tools, since then we'd be bound (either by the license, or
> morally anyway) to include the source as well, and then we'd have to
> keep it up-to-date (and deal with somewhat automatic updates and
> whatnot).
> 
> This said, that is still a very much acceptable point in the
> design space for some cases.
> 
> A very different design point might be to try to guess the kind of
> "package management" in use (msys, apt, guix, ...), then build
> a sequence of commands to pass to that package management, show it to
> the user, and ask them to run them (or to confirm that they want Emacs
> to run them).
> 
> Another design point is to display to the user a text box explaining
> what they need to install and where they can find instructions to do so.
> 
> ...
> 
> 
>        Stefan
> 

Does that mean a external-tool.el that automatically downloads executables is 
not viable?

Yuan