Subject: Re: bug#79470: [PATCH] backward-sentence: Fix inaccuracy in manual's description

From: ERIC Frederickson <[email-masked]>
Date: Fri, 19 Sep 2025 13:13:20 -0500

On Fri, Sep 19, 2025 at 12:50 AM Manuel Giraud <[email-masked]>
wrote:

>> When describing the behavior of 'backward-sentence', the manual states
>> that this command leaves point "just before the first character of the
>> sentence".  This is incorrect, as 'backward-sentence' actually leaves
>> point _on_ the first character of the sentence.

> Hi Eric,

Hi Manuel,

Thanks for your reply.

> I think that "just before" is also correct because the point of
> insertion *really is* just before the first character of the sentence.
> And IMO, in this regard, "just before" is more precise than "on the
> character".

You are correct.  I had been misunderstanding the term "point" to mean
"cursor", and somehow did not see this mistake when exploring this
(non-)issue.

>> When I first saw this, I thought I had to be missing something, but
>> after reading through adjacent docs to make sure I had the right
>> interpretation of point being "on" a character vs "before"/"after" it,
>> and then multi-checking that I wasn't simply misreading the manual, I
>> came to the conclusion that patching this description to use the word
>> "on" instead of the words "just before" would be worthwhile.

> Do you have example of such usage of "on"?

I didn't have any exact examples, but did have some pieces of
"supporting evidence", which are now irrelevant as such, since I was
reading them with the same misunderstanding as the manual text I was
trying to fix.  In case someone is interested though, one such piece
comes from the Elisp manual's description of 're-search-backward'
(which is used under the hood by 'backward-sentence'), which says
that:

     "This function searches backward in the current buffer for a
     string of text that is matched by the regular expression REGEXP,
     leaving point at the beginning of the first text found."

I had been interpreting the word "at" to be synonymous with "on", due
to my aforementioned misunderstanding of point vs cursor.

Sorry for the noise on this,
--
Eric Frederickson