Homepage: http://www.dur.ac.uk/p.j.heslin/Software/Emacs
Author: Peter Heslin
Updated:
Switch flyspell language according to LaTeX
This package examines the LaTeX code around point to discover the
language of the current text, and then it caches that value in a
text-property. This means that, if you modify or add a Babel
command to change the language of some text, the current language
may be out of sync with the cached value. In this case, you can
just stop typing for a bit, and the surrounding text will be
re-parsed, and the new, correct language should be determined. The
length of time that Emacs is idle before this re-parsing happens is
configurable via the variable flyspell-babel-delay (default is 5
seconds).
The parsing done by this package has its limits limited, and so it
will not work with arbitrary LaTeX code. I hope that these
restrictions will not in practice impinge on the typical usage of
most people. The first language declaration is usually determined
by the final language option passed to the babel \usepackage
command, which takes effect after \begin{document}. Thereafter,
you can switch the declared language with \selectlanguage
statements, otherlanguage environments, and \foreignlanguage
commands. You can also define your own language-switching
commands, and register these with flyspell-babel.
This package does not understand complex LaTeX constructs, such as
\input. If you want to set the default language for a particular
file (for example, one that has no Babel declaration, but is going
to be \input into a file that does), you can just put a redundant
\selectlanguage declaration at the start of the file. You can
limit the scope of a \selectlanguage declaration by putting an
opening brace immediately before it, and flyspell-babel will
respect that scoping, but not otherwise, since that would make the
task of parsing too complex.
By default, an ispell dictionary is invoked with the same name as
the current Babel language or dialect, which works in many cases.
If your ispell has a different name for that language, you have two
options. You can make ispell recognize the Babel name by adding
symlinks under that name in your Ispell directory. Alternatively,
you can customize flyspell-babel-to-ispell-alist, which maps Babel
languages and dialects to Ispell language names. If you map a
language to 'nil, that means not to spell-check that language,
which can be useful for languages without an ispell dictionary.
Customization:
The code that follows is an example of my customization of this
package. The first form tells the package to turn on debugging
messages to see when we switch dictionaries as we move from place
to place. The second tells it not to spell-check the languages
"latin" and "ibycus" (an encoding for ancient Greek), since I don't
have ispell dictionaries for them; it also tells it to translate
the Babel language "french" to the ispell dictionary "francais".
The third form defines some language-switching shortcut commands,
so that I can more easily say \fr{merci} and \itl{grazie}. The
fourth defines some short-cut environments, since \begin{german} is
a lot easier to write than \begin{otherlanguage}{german}. The last
form defines some shortcut declarations for switching between
American and British spelling.
(setq flyspell-babel-verbose t)
(setq flyspell-babel-to-ispell-alist
'(("latin" nil)
("ibycus" nil)
("french" "francais")))
(setq flyspell-babel-command-alist
'(("lat" "latin")
("gk" "ibycus")
("fr" "french")
("ger" "german")
("itl" "italian")))
(setq flyspell-babel-environment-alist
'(("latin" "latin")
("greek" "ibycus")
("french" "french")
("german" "german")
("italian" "italian")))
(setq flyspell-babel-declaration-alist
'(("yank" "american")
("brit" "british")))
Here is the LaTeX code that defines these short-cuts:
\usepackage[ibycus,latin,french,german,italian,british,american]{babel}
\newcommand{\lat}[1]{\foreignlanguage{latin}{\emph{#1}}}
\newenvironment{latin}{\begin{otherlanguage}{latin}}{\end{otherlanguage}}
\newcommand{\fr}[1]{\foreignlanguage{french}{\emph{#1}}}
\newenvironment{french}{\begin{otherlanguage}{french}}{\end{otherlanguage}}
\newcommand{\ger}[1]{\foreignlanguage{german}{\emph{#1}}}
\newenvironment{german}{\begin{otherlanguage}{german}}{\end{otherlanguage}}
\newcommand{\itl}[1]{\foreignlanguage{italian}{\emph{#1}}}
\newenvironment{italian}{\begin{otherlanguage}{italian}}{\end{otherlanguage}}
\newcommand{\yank}{\selectlanguage{american}}
\newcommand{\brit}{\selectlanguage{british}}