Re: [Docutils-develop] Babel without Korean

[Guenter M. <mi...@us...>]

Dear Hoze,

thank you for reporting.

On 2022-03-04, Hoze wrote:

> In Babel class of the docutils.writers.latex2e module,
> the language_codes variable lacks 'ko': 'korean'.

> That causes a warning message, "no Babel option known for language
> 'ko'" every time I run sphinx or jupyter-book. It makes nearly no
> problem, yet annoying.

> It'll be appreciated if you add 'ko': 'korean'.

There are a number of problems:

1. Missing Babel support:

After adding 'ko': 'korean':: 

  diff --git a/docutils/docutils/writers/latex2e/__init__.py b/docutils/docutils/writers/latex2e/__init__.py
  index 71ac6bebe..6e62ac131 100644
  --- a/docutils/docutils/writers/latex2e/__init__.py
  +++ b/docutils/docutils/writers/latex2e/__init__.py
  @@ -356,6 +356,7 @@ class Babel:
           'is':           'icelandic',
           'it':           'italian',
           'ja':           'japanese',
  +        'ko':           'korean',
           'kk':           'kazakh',
           'la':           'latin',
           'lt':           'lithuanian',

I get a minimal LaTeX document::

  \documentclass[a4paper]{article}
  % generated by Docutils <https://docutils.sourceforge.io/>
  \usepackage{cmap} % fix search and cut-and-paste in Acrobat
  \usepackage{ifthen}
  \usepackage[T1]{fontenc}
  \usepackage[utf8]{inputenc}
  \usepackage[korean,english]{babel}
  
  
  %%% Body
  \begin{document}
  
  한국어(韓國語)또는
  
  \end{document}

However, this does not compile. The error is ::

  ! Package babel Error: Unknown option `korean'. Either you misspelled it
  (babel)                or the language definition file korean.ldf was not found
  .

I cannot find a Babel language file "korean.ldf" on CTAN. So, IMO, the
currently reported error is correct: the LaTeX package Babel does not
support Korean, there is "no Babel option known for language 'ko'".

2. It works with "Polyglossia" (and `xelatex` or `lualatex`):

What I do find is "latex/polyglossia/gloss-korean.ldf", so it makes
sense, to add ``'ko': 'korean'`` to the polyglossia languages supported by
the "xetex" writer (for the UTF8-aware LaTeX engines `xelatex` and `lualatex`).

Testing the minimal example does not work out of the box, because the
default font "LatinModern" does not support the Korean script.
However, this can be soved by users via a custom LaTeX preamble or stylesheet,
e.g. ::

  \usepackage{fontspec}
  \setmainfont{Noto Sans CJK SC}[Language=Korean]

2. Sphinx uses a fork of the Docutils "latex" writer that is
   developed independently. Any fixes in Docutils will not
   help users of Sphinx -- unless ported over by Sphinx developers.
   
   I don't know about the situation with jupyter.
   
Günter