Re: lines and regexp

[Benno Schulenberg]

Op 07-09-2022 om 18:57 schreef Mike Scalora:
> I noticed something curious about lines and regexp search and replace in 
> nano. If
> I open a file with two lines which nano reports the number of lines on open 
> and
> search and "replace all" on the regexp $ (or ^), I get 3 replacements. It 
> doesn't
> matter if the second line in the file has a newline or not, I get the same 
> result
> because nano adds the second newline automatically. This contradicts nano's
> reporting of the number of lines read and adds yet another line to the file.

This latter thing is why 'nonewlines' became the default in nano-4.0.  (But it
was quickly reverted in nano-4.1, because wanting to add something at the end
of the file had become a nuisance: after M-/ one had to type <End> and <Enter>
first.)

The user can easily prevent the unexpected replacement and the addition of the
extra new line by specifying 'set nonewlines' in their ~/.nanorc.  But using
this option results in the mentioned nuisance, so I don't think most users
would want that.

Alternatively, we could change nano's behavior as in the attached patch, that
prevents any non-explicit replacement on the magic line.  Opinions?

>   ==$ nano /tmp/test.txt
>   ^w^r$<return><space>pie<return>a^s^x

Apparently you have 'set regexp' in your ~/.nanorc.  I have not, and start a
replacement session always with M-R (not ^W^R), followed by another M-R when
I want to do a regex replacement.

> Idea: Remove the trailing newline during the regexp operation.

The patch prevents the replacement on the magic line and thus prevents the
addition of a new magic line.

> I didn't see a way to actually search for a newline

There is none.  Section 3.6 in the info manual (`info nano edit search`)
mentions: "A regular expression in a search string always covers just one line".
Suggestions on how to improve the wording in this section are welcome.

Benno

prevent-replacement-on-the-magicline.patch
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