From: Stefan Monnier <monnier@iro.umontreal.ca>
To: Yuan Fu <casouri@gmail.com>
Cc: emacs-devel <emacs-devel@gnu.org>
Subject: Re: Distinguish between regional undo and undo to the beginning in undo-equiv-table
Date: Wed, 03 Mar 2021 17:28:33 -0500 [thread overview]
Message-ID: <jwvmtvjop1v.fsf-monnier+emacs@gnu.org> (raw)
In-Reply-To: <A371A62F-E3D8-498A-A9F9-14FFA68D229C@gmail.com> (Yuan Fu's message of "Wed, 3 Mar 2021 16:59:52 -0500")
> Yes, that was supposed to be the one. Just to be sure I ran the test with
> the old version and it didn’t error. Oops! I fixed the test, now it errors
> on the old version and passes after applying my fix (in the first
> patch). The test first runs undo in region, then breaks the undo chain (my
> 2nd patch failed to do that), then runs undo in region again.
Perfect.
> I’m not sure how to write the comment for that test. Maybe I could
> write “test for commit xxx” but there is no commit number to refer to
> right now.
That would be fine. Or just use some description of what the test does
like "check the case of interrupted+repeated undo-in-region".
Or just nothing at all and let the code speak for itself ;-)
> BTW, I can’t quite get what the comment at simple.el:2920 means:
>
> (puthash list
> ;; Prevent identity mapping. This can happen if
> ;; consecutive nils are erroneously in undo list.
> (if (or undo-in-region (eq list pending-undo-list))
> t
> pending-undo-list)
> undo-equiv-table)
> Is it that if there is (nil nil nil) on the top of buffer-undo-list,
> the middle one will be considered an undo record and will be passed to
> primitive-undo?
I think so, yes.
> In that case nothing is done and nothing is added to buffer-undo-list?
Exactly.
> 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.
Stefan
next prev parent reply other threads:[~2021-03-03 22:28 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 20:40 Distinguish between regional undo and undo to the beginning in undo-equiv-table Yuan Fu
2021-03-02 23:50 ` Stefan Monnier
2021-03-03 15:42 ` Yuan Fu
2021-03-03 16:50 ` Stefan Monnier
2021-03-03 20:33 ` Yuan Fu
2021-03-03 21:29 ` Stefan Monnier
2021-03-03 21:59 ` Yuan Fu
2021-03-03 22:08 ` Yuan Fu
2021-03-03 22:28 ` Stefan Monnier [this message]
2021-03-04 16:18 ` Yuan Fu
2021-03-05 15:57 ` Stefan Monnier
2021-03-06 17:28 ` Yuan Fu
2021-03-06 18:40 ` Stefan Monnier
2021-03-11 17:50 ` Yuan Fu
2021-03-11 17:54 ` Stefan Monnier
2021-03-11 21:23 ` Yuan Fu
2021-03-11 22:41 ` Stefan Monnier
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