Automatic minor modes?

[Lars Ingebrigtsen]

I was going to write a mode for ~/.authinfo and ~/.netrc that would
cover up the passwords visually so that things are slightly less "eek"
if somebody should happen to walk behind you while you're editing that
file.

But then it was suggested that this should be a minor mode, and that
makes sense: There might well be other kinds of files where you'd rather
cover stuff up, and the minor mode could allow hooks to define syntaxes
and stuff.

But then back to the original remit: ~/.authinfo.  So I now have to
write a major mode for ~/.authinfo that will basically do nothing else
than switch this new minor mode on...  er...  `hide-passwords-mode',
let's call it.

Do we have a method for this?  That is, a way to say "this major mode
will activate these minor modes, unless the user has disabled that"?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no