Occur buglet

Occur buglet

[Morten Welinder]

On fencepost.gnu.org (Emacs 21.2.1) with a buffer containing

--------------------------------------------
+++
+
 hi
xxx
--------------------------------------------

I do the command `M-x occur RET ^[+][^+] RET' and get

--------------------------------------------
1 line matching "^[+][^+]" in buffer *scratch*.
      2:+
       : hi
--------------------------------------------

It is debatable whether there should be a match -- grep would not have
found it -- but the listed thing is not one line, but two.

Morten

Re: Occur buglet

[Andreas Schwab]

Morten Welinder <terra@gnu.org> writes:

> On fencepost.gnu.org (Emacs 21.2.1) with a buffer containing
>
> --------------------------------------------
> +++
> +
>  hi
> xxx
> --------------------------------------------
>
> I do the command `M-x occur RET ^[+][^+] RET' and get
>
> --------------------------------------------
> 1 line matching "^[+][^+]" in buffer *scratch*.
>       2:+
>        : hi
> --------------------------------------------
>
> It is debatable whether there should be a match -- grep would not have
> found it -- but the listed thing is not one line, but two.

Not a bug.  [^+] matches newline in Emacs, but not in grep.  The second
line is actually part of the first match.

Andreas.

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE Linux AG, Maxfeldstraße 5, 90409 Nürnberg, Germany
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"And now for something completely different."

Re: Occur buglet

[era]

On Fri, 05 Mar 2004 14:50:50 -0500, Morten Welinder <terra@gnu.org>
posted to bug-gnu-emacs:
 > 1 line matching "^[+][^+]" in buffer *scratch*.
 >       2:+
 >        : hi
 > It is debatable whether there should be a match -- grep would not have
 > found it -- but the listed thing is not one line, but two.

The string which matches [^+] is the newline of line 2. Emacs regex
negated classes will include newline unless you explicitly exclude it.
The regex [^+\n] matches what you'd express as [^+] in grep. Since
grep is line-oriented, but Emacs is buffer-oriented, this distinction
makes sense.

Furthermore, there is nowhere any assertion that occur and grep should
match exactly the same things -- there are numerous other differences,
all of which are hopefully adequately documented.

/* era */

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