Possible misleading example in `Incremental Search' Info node

Possible misleading example in `Incremental Search' Info node

[Udyant Wig]

I was reading the _Incremental_Search_ Info node in the Emacs manual.
In "15.1.4 Special Input for Incremental Search", found via

    (info "(emacs)Special Isearch")

the second paragraph discusses "lax space matching", and its second and
third sentences read as follows in my version of Emacs:

    Hence, ‘foo bar’ matches ‘foo bar’, ‘foo bar’, ‘foo bar’, and so on
    (but not ‘foobar’).  More precisely, Emacs matches each sequence of
    space characters in the search string to a regular expression
    specified by the variable ‘search-whitespace-regexp’.

I have not modified the default value for `search-whitespace-regexp',
which, for me, is

    search-whitespace-regexp
    => "\\s-+"

From my understanding of that full paragraph, the following illustrates
the default behaviour.  Suppose that we have the text

foobar
foo bar
foo  bar
foo   bar

If point is at the first `f' of `foobar', and I start an incremental
search via C-s for `foo bar', then all three of `foo bar', `foo  bar',
and `foo   bar' are highlighted, the latter two using the
`lazy-highlight' face.

Were the three instances of `foo bar' in the Info node paragraph meant
to have an increasing number of spaces?  Does anyone else see this?

My Emacs version is:

(emacs-version)
=> "GNU Emacs 24.4.1 (x86_64-pc-linux-gnu, GTK+ Version 3.14.5)
    of 2015-03-08 on trouble, modified by Debian"

-- 
Udyant Wig

Re: Possible misleading example in `Incremental Search' Info node

[Emanuel Berg]

Udyant Wig wrote:

> Hence, ‘foo bar’ matches ‘foo bar’, ‘foo
> bar’, ‘foo bar’, and so on (but not
> ‘foobar’). More precisely, Emacs matches each
> sequence of space characters in the search
> string to a regular expression specified by
> the variable ‘search-whitespace-regexp’.

All examples with foo and bar are lazy and
unpedagogical at best and incomprehensible
at worst.

Show this to 100 people in the street without
further explanations and ask them explain what
happens and then compile the outcome what came
up on top carrying thru:

    (concat "It takes two" " to tango.") ; -> "It takes two to tango."

    (concat "foo"          "bar")        ; -> "foobar"

Worst thing tho is people when they don't know
what to call a thing calls it "foo"! Then this
lingers on in the code! H-e-l-l-o? Even

    1) Think

    2) Call it the first thing you think of

is better than to call it "foo" because then no
matter how bad an outcome at least you got some
practise using that thing! (The kidney, I mean.)

-- 
underground experts united .... http://user.it.uu.se/~embe8573
Emacs Gnus Blogomatic ......... http://user.it.uu.se/~embe8573/blogomatic
                   - so far: 64 Blogomatic articles -                   

RE: Possible misleading example in `Incremental Search' Info node

[Drew Adams]

> I was reading the _Incremental_Search_ Info node in the Emacs manual.
> In "15.1.4 Special Input for Incremental Search", found via
> 
>     (info "(emacs)Special Isearch")
> 
> the second paragraph discusses "lax space matching", and its second and
> third sentences read as follows in my version of Emacs:
> 
>     Hence, 'foo bar' matches 'foo bar', 'foo bar', 'foo bar', and so on
>     (but not 'foobar').  More precisely, Emacs matches each sequence of
>     space characters in the search string to a regular expression
>     specified by the variable 'search-whitespace-regexp'.
> 
> From my understanding of that full paragraph, the following illustrates
> the default behaviour.  Suppose that we have the text
> 
> foobar
> foo bar
> foo  bar
> foo   bar

Good catch.  I've reported that regression (using `M-x report-emacs-bug')
as bug #24151.

http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24151

Re: Possible misleading example in `Incremental Search' Info node

[Eli Zaretskii]

> Date: Thu, 4 Aug 2016 07:21:06 -0700 (PDT)
> From: Drew Adams <drew.adams@oracle.com>
> 
> > I was reading the _Incremental_Search_ Info node in the Emacs manual.
> > In "15.1.4 Special Input for Incremental Search", found via
> > 
> >     (info "(emacs)Special Isearch")
> > 
> > the second paragraph discusses "lax space matching", and its second and
> > third sentences read as follows in my version of Emacs:
> > 
> >     Hence, 'foo bar' matches 'foo bar', 'foo bar', 'foo bar', and so on
> >     (but not 'foobar').  More precisely, Emacs matches each sequence of
> >     space characters in the search string to a regular expression
> >     specified by the variable 'search-whitespace-regexp'.
> > 
> > From my understanding of that full paragraph, the following illustrates
> > the default behaviour.  Suppose that we have the text
> > 
> > foobar
> > foo bar
> > foo  bar
> > foo   bar
> 
> Good catch.  I've reported that regression (using `M-x report-emacs-bug')
> as bug #24151.
> 
> http://debbugs.gnu.org/cgi/bugreport.cgi?bug=24151

This was already reported some time ago and is fixed in the 25.1
release candidate.