Re: Distinguish between regional undo and undo to the beginning in undo-equiv-table

[Stefan Monnier]

>>> Then should we add a mapping for the buffer-undo-list to t at that
>>> point?  Or should we just do nothing?
>> Good question.  I think you have a better understanding of how the equiv
>> table should be filled than I do at this point, so I'd trust your judgment.
> Ok, I looked into it in detail, undo-equiv-table is also used to check if
> the previous command is really an undo, alongside with checking
> last-command.

Indeed [ tho, this test is not 100% reliable, because the hash-table is
weak, so entries may disappear from it, leading to entries that used to
map to non-nil suddenly mapping to nil.  ]

> So the undo record has to map to something, I decide to map it to
> ‘empty unless there is already a mapping for the record.  Here is the
> (standalone) final draft. Please have a look.

Looks good, thanks.


        Stefan