RE: widen-one-level [was: Emacs's handling of line numbers]

[Drew Adams]

> If we add a stack of buffer boundaries, we need an easy way to pop
> out of all levels.  The natural thing is that ESC ESC ESC 
> should do it.

Try the code I pointed to:
http://www.emacswiki.org/emacs/wide-n.el

You have these ways to widen completely:

1.     C-x n w  (ordinary `widen')
2. C-u C-x n x  (equivalent to `widen')
3. C-0 C-x n x  (widen and empty the ring)

#1 and #2 leave the ring as it was. #3 empties the ring.

You can cycle among restrictions by repeating `x':
`C-x n x x x x...'.

You can use a numeric prefix arg (e.g. `C-3 C-x n x') to restore a particular
restriction from the ring. A negative prefix arg does that too, but it also pops
off all entries up to the target one.

IOW, if you use a negative prefix arg, you get stack behavior:
`C-x n n' pushes, and `C-- C-x n x' pops'.