Re: master 2ef6f943abd: Add option to control default outlining in 'C-h b'

[Michael Heerdegen]

Eli Zaretskii <eliz@gnu.org> writes:

> What is the purpose of requesting a custom function to actually
> hide/unhide the headings, i.e. to know enough about the structure and
> internal details of Outline mode to do its job?

I guess the idea is to let the user decide _how_ to unhide a sublevel:
reveal only one level, N levels, everything, only a certain leaf and
its parents, etc.  That's a useful feature.

A nice semantics for the custom-function, although not backward
compatible, that would still allow doing this, could be: if the non-nil
return value of the custom-function is functionp, we call it.  Other
non-nil values mean we perform some default action, like showing the
complete subbranch.

Michael.