[R-pkg-devel] .Rd, LaTeX and Unicode

[Serguei Sokol]

On 18/06/2019 17:10, Georgi Boshnakov wrote:
> 
> Since April 2018 'utf8' is the default input encoding in LaTeX, see
> http://anorien.csc.warwick.ac.uk/mirrors/CTAN/macros/latex/doc/ltnews.pdf and they added some symbols in December.
Interesting ... but still not sufficient. I have a fairly recent latex 
system:
$ latex --version
pdfTeX 3.14159265-2.6-1.40.19 (TeX Live 2018/Mageia)

but unfortunately utf8 alone (and even including
\usepackage[mathletters]{ucs}) cannot compile utf8 math expressions.

I have also tried a full scale test on a tex file obtained with
$ R CMD Rd2pdf --no-clean pkgname
where I replaced

\usepackage[utf8]{inputenc}

by

\usepackage[mathletters]{ucs}
\usepackage[utf8x]{inputenc}

and it did not compile either. In addition, I had to replace every 
occurrence of

\inputencoding{utf8}

by

\inputencoding{utf8x}

after what pdflatex worked like a charm.

Serguei.

> 
> -----Original Message-----
> From: R-package-devel [mailto:r-package-devel-bounces using r-project.org] On Behalf Of Martin Maechler
> Sent: 18 June 2019 15:01
> To: serguei.sokol using gmail.com; Hugh Parsonage
> Cc: r-package-devel using r-project.org
> Subject: Re: [R-pkg-devel] .Rd, LaTeX and Unicode
> 
>>>>>> Hugh Parsonage
>>>>>>      on Tue, 18 Jun 2019 20:03:41 +1000 writes:
> 
>      > utf8x is deprecated
>      > https://tex.stackexchange.com/questions/13067/utf8x-vs-utf8-inputenc#13070
> 
> Hmm... interestingly, I've tried quite a few versions of the
> above which started in 2011, but had been updated in April 2016 :
>     https://tex.stackexchange.com/a/203804/7228
> from where it seems that
> 
>       	\usepackage[T1]{fontenc}
> 	\usepackage[utf8]{inputenc}
> 
> should be sufficient.  Further, note that from
>    https://tex.stackexchange.com/a/238135/7228
> the {ucs} package should no longer be needed since ca. 2013,
> hence your \usepackage[mathletters]{ucs}  would not be needed either.
> 
> HOWEVER:  After losing at least half an hour now, trying many
> variants I found that the only version that works correctly for
> me (with a teTeX / TeXlive version of 2018) is the version
> Serguei Sokol proposes (below), including the use of the 'utf8x'
> option *and* the 'ucs' package ...
> 
> which is pretty surprising after having read the
> tex.statexchange threads ...
> 
>      > On Tue, 18 Jun 2019 at 7:52 pm, Serguei Sokol <serguei.sokol using gmail.com>
>      > wrote:
> 
>      >> Hi,
>      >>
>      >> I am preparing a package where I would like to use UTF characters in .Rd
>      >> files. When the LaTeX comes to play, I got well known errors e.g.:
>      >> ! Package inputenc Error: Unicode character ∂ (U+2202)
>      >> (inputenc)                not set up for use with LaTeX.
>      >>
>      >> It is coherent with what is said on this page
>      >> https://developer.r-project.org/Encodings_and_R.html :
>      >> "Since LaTeX cannot handle Unicode we would have to convert the encoding
>      >> of latex help files or use Lambda (and tell it they were in UTF-8)."
> 
> That whole document has been very important and crucial, written
> by Prof Brian Ripley  who had worked a *LOT* to bring unicode to R,
> -- but it has been written 2004-2005  and indeed, I think it is
> probably fair to say that the above sentence no longer applies
> to current LaTeX engines (including "simple" pdflatex)... though really,
> I'm not the expert here, but I think it's a good point in time
> to reconsider how much UTF8 should be allowed/supported in *.Rd files.
> 
> One problem: This is (slightly) the wrong mailing list; this would have
> been a perfect topic for 'R-devel' (discussing about new
> features etc for R) instead....
> ( but we'd rather keep it here for now.)
> 
> Martin Maechler
> ETH Zurich and R Core Team
> 
> 
> 
>      >> But LaTeX can support UTF8 as shown with this small example:
> 
>   \documentclass{article}
>   \usepackage[mathletters]{ucs}
>   \usepackage[utf8x]{inputenc}
>   
>   \begin{document}
>   The vorticity ω is defined as $ω = ∇ × u$.
>   \end{document}
> 
>      >> I can compile it with my LaTeX without problem. May be you too?
>      >> So my suggestion would be to place these two lines somewhere in LaTeX
>      >> header generated by R doc system:
>      >> \usepackage[mathletters]{ucs}
>      >> \usepackage[utf8x]{inputenc}
>      >>
>      >> Note "utf8x" and not just "utf8" which is crucial for this example.
>      >> With a hope that it would fix unicode errors from LaTeX.
>      >>
>      >> Best,
>      >> Serguei.
> 
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