R scripts attached to e-mails - correct MIME type ?!

On Mon, 20 Feb 2017 15:15:27 +0100 Martin Maechler <maechler at stat.math.ethz.ch> wrote:

Rui Barradas <ruipbarradas at sapo.pt>
    on Sat, 18 Feb 2017 13:47:02 +0000 writes:

    > Helo, No attachment came through. Change the file
    > extension from .R to .txt and resend, there aren't many
    > types of files r-help accepts.

    > Rui Barradas

As a matter of fact, one would have to blame the e-mail program
you use.  The file extension is *not* equivalent to the file
type, and the mailing list software accepts the (MIME) type  text/plain
and a couple of others.

The problem with most modern e-mail clients/programs/apps/... is that
they use something you could translate as  "unknown binary format"
as type for their attachments if they can't guess the correct
file type from the file extension.
It would be interesting to know (for me) if there are modern
e-mail programs / web apps which you could *teach* about the
mime type, e.g., for all files ending with extension '.R'...

Well, there's Gnus in Emacs:

(add-to-list 'mailcap-mime-extensions '(".R" . "text/x-rsrc"))

But I guess you know that ;-)