Using babel with Plain

(Under development)

As explained in the manual, not all languages provide a sty file and some of them are not compatible with Plain. This document will explain how to use babel with Plain, because the information in the manual (for LaTeX) is almost non-existent (just a few lines).

Currently, support for Plain is mostly in a maintenance mode, which means many of the features added in the last few months (well, years) won’t work.

It is worth noting Babel is not compatible with the original Plain but rather with a format named bplain (admittedly, the manual is somewhat misleading in this regard). Apparently this format has never found its way into most of distributions. Version 3.9 added support for e-Plain, because the changes to achieve it were minimal. When the manual refers to Plain, it actually means e-Plain and pdf-Plain, which are the formats used de facto in most cases.

User’s level

Here is a minimal working example with two languages:

\input dutch.sty
\input danish.sty  % Last language, and therefore the main one
\begindocument

\chaptername---\today

\foreignlanguage{dutch}{\chaptername---\today}

\selectlanguage{dutch}

\chaptername---\today

\bye

Which prints (the date will be different, of course):

Kapitel—14. april 2021
Kapitel—14. april 2021
Hoofdstuk—14 april 2021

The optional argument works, so:

\foreignlanguage[captions]{dutch}{\chaptername---\today}

will print ‘Hoofdstuk’.

This is basically all what you can do with Plain TeX, although in some languages there will be additional features (for example, with spanish \sen is correctly recognized) and shorthands are usually recognized (it depends on how they have been defined). For example:

\input danish.sty
\begindocument

"< "> f"|i

\bye

Everyting related to \babelprovide and the ini mechanism won’t work, including \babelfont. Obviously, features activated as package options won’t work either.

Hooks work when they make sense, which is particularly useful in Plain’s DIY philosophy. For example:

\AddBabelHook[danish]{font}{beforeextras}{\it}

Developer’s level

There must be a sty proxy file. See the existing ones.

As ldf files may contain arbitrary TeX/LaTeX code, there is no safe rule that can be applied.

Babel defines some LaTeX macros, but many of them are just dummy definitions just to avoid errors or simplified versions.

(….. More to follow.)

Languages

Here is a document which runs with no error messages in pdfTeX and ePlain, but with an error in latin in TeX. Note two points: all of them use the Latin script, and there is only a set of hyphenation patterns (English):

\input afrikaans.sty
\input albanian.sty
\input american.sty
\input austrian.sty
\input bahasa.sty
\input bahasam.sty
\input basque.sty
\input breton.sty
\input british.sty
\input catalan.sty
\input croatian.sty
\input danish.sty
\input dutch.sty
\input esperanto.sty
\input estonian.sty
\input finnish.sty
\input germanb.sty
\input icelandic.sty
\input interlingua.sty
\input irish.sty
\input latin.sty
\input lsorbian.sty
\input naustrian.sty
\input norsk.sty
\input polish.sty
\input portuges.sty
\input romanian.sty
\input samin.sty
\input scottish.sty
\input serbian.sty
\input slovene.sty
\input swedish.sty
\input turkish.sty
\input UKenglish.sty
\input USenglish.sty
\input usorbian.sty
\begindocument

\bye