Re: search-forward in emacs23 lisp

[rasmith]

From: Lennart Borgman <lennart.borgman@gmail.com>
Subject: Re: search-forward in emacs23 lisp
Date: Sun, 28 Mar 2010 18:50:46 +0200

> On Sun, Mar 28, 2010 at 6:39 PM,  <rasmith@tamu.edu> wrote:> Sorry to
> reply to my own post, but the following rather ugly solution
>> solves the problem of finding a single FF byte:
>>      (while (/= (char-after) ?\377)
>>        (forward-char 1)
>>        )
>>      (forward-char 1)
>> This replaces
>>      (search-forward (unibyte-string ?\377))
>> which, in emacs23, no matter what I do, insists on turning the byte
>> into the two-byte string \231\277 before searching.
>>
>> But surely there's a better way?
> 
> Hi Robin,
> 
> Someone else knows this much better than me and can explain the
> details, but I believe that unibyte-string is a low level function
> that you do not need here.
> 
> How about just
> 
>    (search-forward (char-to-string ?\377))
>    or (search-forward (char-to-string 255))
> 
> Does that work for you?

Nope.  That's exactly what caused the original problem (that is, the
code that broke was exactly what you suggest).  Using either one of
these, what search-forward will look for is a two-byte string (in
other words, it undertakes to convert the high 8-bit character into
something like a utf-8 representation of it (\377 can't occur as the
first byte of a utf-8 character, which is probably what triggers
this).

Robin Smith