bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Richard Stallman]

1. Char-fold isearch is a screw.  I wanted to search for lines
starting with a space, so I searched for C-j SPC, but it did something
useless.  It found every blank line!

2. So I decided to try to disable it, but the doc string of
isearch says nothing about how to turn that off.  It should say how.

3. I tried using C-h v to find a variable, but although there is
isearch-case-fold-search, there is no isearch-char-fold-search.
For parallelism's sake, isearch-char-fold-search should exist.

4. I searched in etc/NEWS for 'char fold' and 'char-fold'.
Neither appears.  Both of them SHOULD appear, for the sake
of people who search for them.

5. I did find 'isearch', and that entry described the new inconvenient
feature.  However the entry there did not say how to disable this
feature.  It should say how.




In GNU Emacs 25.0.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.23)
 of 2015-08-12 on freetop
Repository revision: 79a169684dfad2c0bbb9fdbae539c1f30d9f0ac3
System Description:	Trisquel GNU/Linux 7.0, Belenos

Configured using:
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[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]


-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Andreas Schwab]

Richard Stallman <rms@gnu.org> writes:

> 1. Char-fold isearch is a screw.  I wanted to search for lines
> starting with a space, so I searched for C-j SPC, but it did something
> useless.  It found every blank line!

That has nothing to do with char-fold, this feature already exists since
24.3 and is called lax-whitespace.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Mark Oteiza]

Richard Stallman <rms@gnu.org> writes:

> 2. So I decided to try to disable it, but the doc string of
> isearch says nothing about how to turn that off.  It should say how.
>
> 3. I tried using C-h v to find a variable, but although there is
> isearch-case-fold-search, there is no isearch-char-fold-search.
> For parallelism's sake, isearch-char-fold-search should exist.
>
> 4. I searched in etc/NEWS for 'char fold' and 'char-fold'.
> Neither appears.  Both of them SHOULD appear, for the sake
> of people who search for them.
>
> 5. I did find 'isearch', and that entry described the new inconvenient
> feature.  However the entry there did not say how to disable this
> feature.  It should say how.

As I understand it, the variables `character-fold-search' and
`replace-character-fold' control the new folding features. I have it all
disabled--both variables set to nil. At least they have docstrings;
however, yes, they need to be documented in isearch, replace, and NEWS.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > That has nothing to do with char-fold, this feature already exists since
  > 24.3 and is called lax-whitespace.

How come it did not occur in the Emacs I was running before last week?
I built that from master a few months ago.

Anyway, it is a total screw.  Who likes this as a default?

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > That has nothing to do with char-fold, this feature already exists since
  > 24.3 and is called lax-whitespace.

If char-fold really only affects ASCII and Unicode lookalikes, is it
important enough to be worth mentioning in the echo area?  If not,
let's delete it from the echo area.

Does anyone really want to disable it?

On the other hand, lax whitespace search by default is a drastic
change.  That should be listed in the echo area, and its default
should be nil.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

When was the change to make lax whitespace mode the default
installed?

I can't find anything in the lisp/ChangeLog* files, which run through the start
of April.

Was it installed after that?  If so, how can I find out when?  There
is no ChangeLog file to search, now.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Tassilo Horn]

Richard Stallman <rms@gnu.org> writes:

>   > That has nothing to do with char-fold, this feature already exists since
>   > 24.3 and is called lax-whitespace.
>
> How come it did not occur in the Emacs I was running before last week?
> I built that from master a few months ago.
>
> Anyway, it is a total screw.  Who likes this as a default?

I like that behavior because I frequently search for "some text" in
prose, and then it allows me to find also the matches where the two
words are wrapped around.

But I think the `isearch-lax-whitespace' feature can still be improved:

1. The `isearch-lax-whitespace' docstring speaks of "ordinary
   incremental search" which I've read as "non-regex isearch".  But it
   seems that regex isearch is also affected.  I'd just strip the
   "ordinary".

2. More importantly, isearching for C-j SPC matches any sequence of two
   whitespace characters, e.g., it matches between here  and  here, too.
                                                       ^^   ^^
I had expected that only space characters in the search string are
replaced by `search-whitespace-regexp' but it seems that any whitespace
character is replaced by it.  I think this is not good.

And IMHO, it would be a good idea to disable lax-whitespace for the
current search as soon as the search string contains a non-space
whitespace character.  I think if the user explicitly types C-j, C-i,
etc. she's probably not interested in treating spaces as any-whitespace
but wants to distinguish newlines from tabs and spaces.

Bye,
Tassilo

Re: When was a change installed?

[Alan Mackenzie]

Hello, Richard.

On Mon, Aug 17, 2015 at 11:42:28PM -0400, Richard Stallman wrote:
> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]

> When was the change to make lax whitespace mode the default
> installed?

It might well have been this change:

commit 63dd1c6fa45357d312e1d3076e15adacf5ed6291
Author: Juri Linkov <juri@jurta.org>
Date:   Sun Sep 2 12:31:45 2012 +0300

    Toggle whitespace matching mode with M-s SPC.
    http://lists.gnu.org/archive/html/emacs-devel/2012-09/msg00008.html


> I can't find anything in the lisp/ChangeLog* files, which run through the start
> of April.

We have given up updating the ChangeLogs with each change, on the
grounds that the information is in the git change log anyway.  I think
the idea is to generate the full ChangeLogs as part of the release
process.

> Was it installed after that?  If so, how can I find out when?  There
> is no ChangeLog file to search, now.

From anywhere inside a local copy of the git repository, type "git log"
(no arguments) on a command line.  This should dump the entire log into
`less'.  You can then search within that (as I have just done).

There will certainly also be a way of getting the log from inside Emacs.

> -- 
> Dr Richard Stallman
> President, Free Software Foundation (gnu.org, fsf.org)
> Internet Hall-of-Famer (internethalloffame.org)
> Skype: No way! See stallman.org/skype.html.

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: When was a change installed?

[Andreas Schwab]

Richard Stallman <rms@gnu.org> writes:

> When was the change to make lax whitespace mode the default
> installed?

In commit emacs-24.2-2394-g63dd1c6.

> I can't find anything in the lisp/ChangeLog* files, which run through the start
> of April.
>
> Was it installed after that?

In Sep 2012.

> If so, how can I find out when?  There
> is no ChangeLog file to search, now.

$ git grep lax-whitespace '*/ChangeLog*'

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Drew Adams]

FYI: This is the thread that discussed this feature, in quite a lot
of detail (behavior, defaults, toggling, chars to match, indication
in echo area or elsewhere, etc.).

http://lists.gnu.org/archive/html/emacs-devel/2012-08/msg00502.html

Re: When was a change installed?

[Tassilo Horn]

Richard Stallman <rms@gnu.org> writes:

> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
>
> When was the change to make lax whitespace mode the default
> installed?

It has been introduced in commit 63dd1c6f by Juri Linkov on 2012-09-02.

> I can't find anything in the lisp/ChangeLog* files, which run through
> the start of April.
>
> Was it installed after that?  If so, how can I find out when?  There
> is no ChangeLog file to search, now.

One way is to invoke `vc-annotate' in the buffer containing its
definition.  That shows you at least the most recent commit changing its
value.

Another way was to mark its definition and invoke `vc-region-history'
which shows you all commits applied to that region.

Both ways require that you run emacs from your git checkout of course.

A third way is to use git directly in your emacs working directory:

  $ git log --grep=isearch-lax-whitespace

which shows all commits where the commit message (which has
traditionally ChangeLog format in emacs) contains the string
isearch-lax-whitespace.

Bye,
Tassilo

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Artur Malabarba]

2015-08-18 13:30 GMT+01:00 Tassilo Horn <tsdh@gnu.org>:
> I like that behavior because I frequently search for "some text" in
> prose, and then it allows me to find also the matches where the two
> words are wrapped around.

Me too, it's very useful in prose. I agree that it's not super useful
in code. But it's also not harmful enough in code that it should be
disabled in prose.

> But I think the `isearch-lax-whitespace' feature can still be improved:
> [...]
> I had expected that only space characters in the search string are
> replaced by `search-whitespace-regexp' but it seems that any whitespace
> character is replaced by it.  I think this is not good.

I agree.

> And IMHO, it would be a good idea to disable lax-whitespace for the
> current search as soon as the search string contains a non-space
> whitespace character.  I think if the user explicitly types C-j, C-i,
> etc. she's probably not interested in treating spaces as any-whitespace
> but wants to distinguish newlines from tabs and spaces.

I'm so sure this would be good, but I'm not sure it would be bad either.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Artur Malabarba]

>> but wants to distinguish newlines from tabs and spaces.
>
> I'm so sure this would be good, but I'm not sure it would be bad either.

I'm NOT so sure...

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Artur Malabarba]

> 2. So I decided to try to disable it, but the doc string of
> isearch says nothing about how to turn that off.  It should say how.
>
> 3. I tried using C-h v to find a variable, but although there is
> isearch-case-fold-search, there is no isearch-char-fold-search.
> For parallelism's sake, isearch-char-fold-search should exist.
>
> 4. I searched in etc/NEWS for 'char fold' and 'char-fold'.
> Neither appears.  Both of them SHOULD appear, for the sake
> of people who search for them.
>
> 5. I did find 'isearch', and that entry described the new inconvenient
> feature.  However the entry there did not say how to disable this
> feature.  It should say how.

All good points. I'll try to address all of these when I can.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > I can't find anything in the lisp/ChangeLog* files, which run through the start
  > > of April.
  > >
  > > Was it installed after that?

  > In Sep 2012.

That is really bizarre.  I have built the latest Emacs sources many
times since 2012, and generally used those builds, but isearch never
treated space and NL as equivalent until now.

What could have caused this?

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > If so, how can I find out when?  There
  > > is no ChangeLog file to search, now.

  > $ git grep lax-whitespace '*/ChangeLog*'

It gives me this output:

fatal: ambiguous argument '*/ChangeLog*': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

Thanks for those suggestions.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[David Kastrup]

Richard Stallman <rms@gnu.org> writes:

> [[[ To any NSA and FBI agents reading my email: please consider    ]]]
> [[[ whether defending the US Constitution against all enemies,     ]]]
> [[[ foreign or domestic, requires you to follow Snowden's example. ]]]
>
>   > > I can't find anything in the lisp/ChangeLog* files, which run
>   > > through the start
>   > > of April.
>   > >
>   > > Was it installed after that?
>
>   > In Sep 2012.
>
> That is really bizarre.  I have built the latest Emacs sources many
> times since 2012, and generally used those builds, but isearch never
> treated space and NL as equivalent until now.
>
> What could have caused this?

commit a5bdb872edb9f031fe041faf9a8c0be432e5f64c
Author: Artur Malabarba <bruce.connor.am@gmail.com>
Date:   Sun Aug 9 09:56:33 2015 +0100

    * isearch.el (isearch-search-fun-default): (Bug#21164)
    
    Respect `isearch-lax-whitespace' when searching through
    `isearch-word'.

or something else out of

git log --grep isearch

-- 
David Kastrup

Re: When was a change installed?

[Steinar Bang]

>>>>> Alan Mackenzie <acm@muc.de>:

> There will certainly also be a way of getting the log from inside Emacs.

For a particular file, just do `C-x v l' to get the history of that
file.

Also, as has been suggested: do `C-x v g' do do annotate, and then do
`l' on a particular line in the annotated file to see the log message
for the last change to that line, or `d' to see the diff of that change.

From vc-dir, I think the command was `l'.

From magit the command is `l l'.

From the list of changes in either, you can quickly get the diff and the
log message, and the list of files changed with that file.

Re: When was a change installed?

[Andreas Schwab]

Richard Stallman <rms@gnu.org> writes:

> fatal: ambiguous argument '*/ChangeLog*': unknown revision or path not in the working tree.

On which branch are you doing that?  There are 55 matches in master.

$ git ls-files origin/master '*/ChangeLog*' | wc -l
55

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: When was a change installed?

[Bastien]

Richard Stallman <rms@gnu.org> writes:

>   > $ git grep lax-whitespace '*/ChangeLog*'
>
> It gives me this output:
>
> fatal: ambiguous argument '*/ChangeLog*': unknown revision or path not in the working tree.
> Use '--' to separate paths from revisions, like this:
> 'git <command> [<revision>...] -- [<file>...]'

$ git grep lax-whitespace */ChangeLog*

without the single quotes works for me.

Re: When was a change installed?

[Andreas Schwab]

Bastien <bzg@gnu.org> writes:

> $ git grep lax-whitespace */ChangeLog*
>
> without the single quotes works for me.

That's not the same, as the glob is expanded by the shell before git can
see it.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

Re: When was a change installed?

[Stephen Berman]

On Wed, 19 Aug 2015 11:25:10 +0200 Andreas Schwab <schwab@suse.de> wrote:

> Bastien <bzg@gnu.org> writes:
>
>> $ git grep lax-whitespace */ChangeLog*
>>
>> without the single quotes works for me.
>
> That's not the same, as the glob is expanded by the shell before git can
> see it.

The error message by git, which I also get on invoking
  git grep lax-whitespace '*/ChangeLog.*'
says "Use '--' to separate paths from revisions, like this: 'git
<command> [<revision>...]  -- [<file>...]'", and indeed, when I run
  git grep lax-whitespace -- '*/ChangeLog.*'
it outputs 26 matching lines.  Invoking
  git grep lax-whitespace */ChangeLog*
outputs only 25 of thos lines, all from lisp/; missing is
  "doc/emacs/ChangeLog.1:	(Replace): Document replace-lax-whitespace."
which the other output contains.

So you're right there's a difference, but apparently the '--' is necessary.

Steve Berman

Re: When was a change installed?

[Damien Wyart]

> > > $ git grep lax-whitespace */ChangeLog*
> > > without the single quotes works for me.

> > That's not the same, as the glob is expanded by the shell before git
> > can see it.

* Stephen Berman <stephen.berman@gmx.net> [2015-08-19 11:57]:
> The error message by git, which I also get on invoking
>   git grep lax-whitespace '*/ChangeLog.*'
> says "Use '--' to separate paths from revisions, like this: 'git
> <command> [<revision>...]  -- [<file>...]'", and indeed, when I run
>   git grep lax-whitespace -- '*/ChangeLog.*'
> it outputs 26 matching lines.  Invoking
>   git grep lax-whitespace */ChangeLog*
> outputs only 25 of thos lines, all from lisp/; missing is
>   "doc/emacs/ChangeLog.1:	(Replace): Document replace-lax-whitespace."
> which the other output contains.

> So you're right there's a difference, but apparently the '--' is necessary.

I guess Andreas is using git 2.5.0, where '--' is not necessary anymore
in this case.

Here is the corresponding item from the release notes:

,----
|  * A heuristic we use to catch mistyped paths on the command line
|   "git <cmd> <revs> <pathspec>" is to make sure that all the non-rev
|    parameters in the later part of the command line are names of the
|    files in the working tree, but that means "git grep $str -- \*.c"
|    must always be disambiguated with "--", because nobody sane will
|    create a file whose name literally is asterisk-dot-see.  Loosen the
|    heuristic to declare that with a wildcard string the user likely
|    meant to give us a pathspec.
`----
                      
-- 
Damien

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > Me too, it's very useful in prose. I agree that it's not super useful
  > in code. But it's also not harmful enough in code that it should be
  > disabled in prose.

It was in prose that it screwed me!  I wanted to search for NL SPC,
but it found NL NL instead.

See another message in this batch
for an idea for making this work better.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

Thanks.  I never used C-x v g before.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > fatal: ambiguous argument '*/ChangeLog*': unknown revision or path not in the working tree.

  > On which branch are you doing that?  There are 55 matches in master.

It fails in master.  Adding '--', as was suggested by Stephen Berman,
made it work.

However, git grep only shows me lines _in the old ChangeLog.* files_,
which I had already searched in Emacs directly.  They describe changes
through 2015-04-06.

I was looking for a way to search changes installed since then.

It appears that git log does the job.

-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

Re: When was a change installed?

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

I finally succeeded in running an Emacs from July 2014.  (Work was
required to make it run.)  I was flabbergasted to find that it DID do
the lax whitespace search.

Has the feature been active for 3 years and I never noticed until now?
It looks that way.

I tried various cases and learned something that might explain
why I didn't notice it.

It seems that the feature applies only to SPC.  Entering C-j matches
only newline.  That seems to explain why my searches for C-j C-j
always worked as intended.

Given that in lax matching SPC matches any sequence of whitespace,
there is no sense in a lax SPC preceded or followed by another
whitespace character.

Thus I propose that SPC adjacent to some other whitespace character
should match only a single space.  In particular C-j SPC should match
only newline space, and SPC SPC should match only space space.

What do people think of that?

Meanwhile, how about colorizing a space in the echo area when it is
being searched for laxly?  That should help users understand what is
happening.



-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Juri Linkov]

> 3. I tried using C-h v to find a variable, but although there is
> isearch-case-fold-search, there is no isearch-char-fold-search.
> For parallelism's sake, isearch-char-fold-search should exist.

There are both case-fold-search and its isearch-specific counterpart
isearch-case-fold-search, so maybe both char-fold-search and
isearch-char-fold-search should exist.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Juri Linkov]

> If char-fold really only affects ASCII and Unicode lookalikes, is it
> important enough to be worth mentioning in the echo area?  If not,
> let's delete it from the echo area.

One idea was to not display default parameters in the echo area.
So when e.g. char-fold search is t by default then it should not
be indicated in the echo area.

> Does anyone really want to disable it?

Like case-fold search, char-fold search could be disabled either by
customizing the corresponding variable, or interactively with ‘M-s '’.

> On the other hand, lax whitespace search by default is a drastic
> change.  That should be listed in the echo area, and its default
> should be nil.

AFAIK, a drastic change was not in lax whitespace search per se, but
only in its combination with char-fold search that we could fix now.

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Juri Linkov]

> But I think the `isearch-lax-whitespace' feature can still be improved:
>
> 1. The `isearch-lax-whitespace' docstring speaks of "ordinary
>    incremental search" which I've read as "non-regex isearch".  But it
>    seems that regex isearch is also affected.  I'd just strip the
>    "ordinary".

Regexp isearch is affected by ‘isearch-regexp-lax-whitespace’.

> And IMHO, it would be a good idea to disable lax-whitespace for the
> current search as soon as the search string contains a non-space
> whitespace character.  I think if the user explicitly types C-j, C-i,
> etc. she's probably not interested in treating spaces as any-whitespace
> but wants to distinguish newlines from tabs and spaces.

Good idea - it could work the same way as case-fold search detects the presence
of uppercase chars in the search string to automatically toggle itself.

Re: When was a change installed?

[Stefan Monnier]

> Thus I propose that SPC adjacent to some other whitespace character
> should match only a single space.  In particular C-j SPC should match
> only newline space, and SPC SPC should match only space space.

> What do people think of that?

Sounds good to me,


        Stefan "who doesn't much like lax whitespace search"

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Artur Malabarba]

[-- Attachment #1: Type: text/plain, Size: 415 bytes --]

> There are both case-fold-search and its isearch-specific counterpart
> isearch-case-fold-search, so maybe both char-fold-search and
> isearch-char-fold-search should exist.

Actually, `isearch-case-fold-search' is an internal variable and
configuring it has no effect. If you want configure isearch's case-folding,
you have to use the general `case-fold-search'.

That is why there's no isearch-char-fold-search.

[-- Attachment #2: Type: text/html, Size: 543 bytes --]

bug#21277: 25.0.50; char-fold search is a screw, and I can't see how to disable

[Richard Stallman]

[[[ To any NSA and FBI agents reading my email: please consider    ]]]
[[[ whether defending the US Constitution against all enemies,     ]]]
[[[ foreign or domestic, requires you to follow Snowden's example. ]]]

  > > If char-fold really only affects ASCII and Unicode lookalikes, is it
  > > important enough to be worth mentioning in the echo area?  If not,
  > > let's delete it from the echo area.

  > One idea was to not display default parameters in the echo area.
  > So when e.g. char-fold search is t by default then it should not
  > be indicated in the echo area.

Might be good.

  > > Does anyone really want to disable it?

  > Like case-fold search, char-fold search could be disabled either by
  > customizing the corresponding variable, or interactively with ‘M-s '’.

Yes, but does anyone really ever want to disable it?

  > > On the other hand, lax whitespace search by default is a drastic
  > > change.  That should be listed in the echo area, and its default
  > > should be nil.

  > AFAIK, a drastic change was not in lax whitespace search per se, but
  > only in its combination with char-fold search that we could fix now.

Is that a certainty?  I now think the problem is simply in lax
whitespace search.  Some evidence is that it occurs in an Emacs from a
year ago, in which char-fold search did not exist.


-- 
Dr Richard Stallman
President, Free Software Foundation (gnu.org, fsf.org)
Internet Hall-of-Famer (internethalloffame.org)
Skype: No way! See stallman.org/skype.html.