%D \module
%D   [       file=m-translate,
%D        version=2008.10.09,
%D          title=\CONTEXT\ Modules,
%D       subtitle=Translations,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=Hans Hagen]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\doifnotmode{mkiv}{\endinput}

%D We can make this module more clever (wildcards and such) but since
%D it's only a demo we stick to the simple case for now. After all, it's
%D better to fix your source.

\startluacode
    translators = { }

    local compiled, list = nil, nil

    function translators.register(from,to)
        local l = lpeg.P(from)/to
        if not list then
            list = l
        else
            list = list + l
        end
        compiled = nil
    end

    function translators.translate(s)
        if list then
            if not compiled then
                compiled = lpeg.Cs((list + lpeg.P(1))^0)
            end
            return compiled:match(s)
        else
            return s
        end
    end

    function translators.reset(s)
        resolvers.install_text_filter("user",nil)
        list, compiled = nil, nil
    end
    function translators.enable(s)
        resolvers.install_text_filter("user",translators.translate)
    end
    function translators.disable(s)
        resolvers.install_text_filter("user",nil)
    end
\stopluacode

\unprotect

\def\translateinput{\dodoubleargument\dotranslateinput}

\def\dotranslateinput[#1][#2]{\ctxlua{translators.register(\!!bs#1\!!es,\!!bs#2\!!es)}}

\def\resetinputtranslation  {\ctxlua{translators.reset()}}
\def\enableinputtranslation {\ctxlua{translators.enable()}}
\def\disableinputtranslation{\ctxlua{translators.disable()}}

\def\readtranslatedfile#1%
  {\enableinputtranslation
   \readfile{#1}\donothing\donothing
   \disableinputtranslation}

\protect

\doifnotmode{demo}{\endinput}

\starttext

    \translateinput[Moica][Mojca]
    \translateinput[Idris][Idris (aka ادريس)]

    \enableinputtranslation

    Well, it's not that hard to satisfy Idris and Moica.

    \readtranslatedfile{tufte}

\stoptext