On Fri, Jun 15 2012, Jani Nikula <jani@nikula.org> wrote:
> Add function notmuch-show-toggle-multipart-alternative to make
> notmuch-show-all-multipart/alternative-parts buffer local, toggle its
> value in the buffer, and redisplay the thread with either all or
> preferred alternative parts expanded.
>
> A small wrinkle is that in order to make the variable survive
> notmuch-show-refresh-view (which is required for expanding/collapsing
> the parts, but ends up calling kill-all-local-variables through
> notmuch-show-mode) it is necessary to give it the permanent-local
> property.

This is a very cool feature.  I haven't looked closely at this but can't
this mechanism work the same as the other show-mode toggles, like crypto
or indenting?  I wouldn't think it would require any more extra variable
stuff than what is used for those other toggles.

Also, the *really* sweet thing would be if the toggle actually cycled
through display of the alternatives, only displaying one at a time.
That would be very swank.

David Edmondson put together the other show-mode toggling stuff, so he
may be able to help with this as well.

jamie.