Re: [AUCTeX] composed characters in LaTeX source code

[Stephen Berman]

On Thu, 8 Nov 2018 21:50:42 +0100 jfbu <address@hidden> wrote:

> Le 08/11/2018 à 21:10, Stephen Berman a écrit :
>> On Thu, 8 Nov 2018 18:58:02 +0100 jfbu <address@hidden> wrote:
>>
>>> Le 08/11/2018 à 18:45, jfbu a écrit :
>>>> Le 08/11/2018 à 18:07, Stephen Berman a écrit :
>>>>> I have a file containing such composed characters that I've imported to
>>>>> a LaTeX file but in the output of pdflatex, the circumflex is displayed
>>>>> over the character following the one it is composed with, e.g., the
>>>>> sequence 'b^a' (where '^' means U+0302, the combining circumflex accent)
>>>>> is displayed in Emacs with the circumflex over 'b' but in the PDF output
>>>>> the circumflex is over 'a'.
>>>>
>>>> Hi
>>>>
>>>> I wanted to test your problem but I have another issue, which is that
>>>> typing
>>>>
>>>> 'xb M-x 8 <RET> 302 <RET>ac'
>>>>
>>>> the 'a' gets superimposed on top of the b in my Emacs buffer:
>>>>
>>>> (see attached image)
>>
>> That's strange, and doesn't happen for me (see the screenshot in my
>> followup to Joost Kremers).  Does it also look like that in emacs -Q?
>> And what version of Emacs?
>
> You are right the problem does not show if using
>
>  /Applications/Emacs.app/Contents/MacOS/Emacs -Q

So something in you initializations or some add-on must be causing it
causing that problem.

> It is a GNU Emacs 26.1
>
> which is a binary build I got from
>
> https://github.com/railwaycat/homebrew-emacsmacport/releases
>
> (emacs-26.1-mac-7.1)
>
> No problem either in the emacs 22 which I launch in a Terminal window (Mac OS 
> X)

You mean no problem with your initializations?  Then I guess it's only
something that affects the graphical display (though I no nothing about
Emacs on Mac OS X).

>
>>
>>>> As per your issue, it is going to be very hard in LaTeX to get the accent 
>>>> on
>>>> top of previous letter. (I think, but my knowledge of Unicode is
>>>> scarce). With LuaLaTeX that could be possible.
>>
>> Haven't tried LuaLaTeX yet, but XeLaTeX does work, though with
>> suboptimal display (see my other followup again).
>
> ok
>
>>
>>>> If really the combining accent is supposedly typed *after*  the letter
>>>> (which sounds strange to me, but again, I am no Unicode-guy).
>>>
>>> Ok, I learned since that's way.
>>>
>>> As per your original question
>>>
>>> https://tex.stackexchange.com/questions/79333/is-there-a-way-to-get-pdflatex-to-accept-unicode-combining-accents
>>>
>>> has a comment by D. Carlisle who said in 2012: I think the answer is "No".
>>>
>>> A further comment by the same, when asked about "peek at previous character"
>>>
>>> yes but you can't go back, you can in simple case write a macro that parses
>>> the entire text stream re-ordering tokens when it sees a combining 
>>> character,
>>> but it would be very fragile and likely break most other package commands. 
>>> If
>>> your accented letters are single characters in Unicode form NFC then
>>> normalising the input before passing to TeX will be a lot more robust.
>>>
>>> (quote from D. C.)
>>>
>>> The available answer recommends using Perl to malax the file and normalize 
>>> the
>>> Unicode characters.
>>
>> Thanks for the URL and quotes; in fact, I had also found that before
>> posting, but I don't think it would work for me anyway, because in my
>> case it's about composed characters for which there are no corresponding
>> single Unicode characters, so nothing to normalize to.
>
> Yes, sorry that I sort of lost sight of that crucial thing,
> but then the follow-up idea would still be to pre-process
> your file via a Perl script or use Emacs eLisp itself
>
> but now to either output LaTeX mark-up such as you mentioned \^{b}a,
>
> or keep the combining diacritic and \DeclareUnicodeCharacter{0302}{\^},
> but move the combining diacritic before the letter.
> With the defect it will not look nice in your Emacs buffer.

Yes, that would defeat the purpose of using the Unicode combining
character in the first place.

> But you have already considered those options.
>
>
> I tried XeLaTeX, result was not good with default fonts, but using
>
> \usepackage{fontspec}
> \setmainfont{Times New Roman}
>
> it seems to work fine.

Yes, I also found changing the font could improve the display.

Steve Berman