%D \module
%D   [       file=lang-lab,
%D        version=1997.08.27,
%D          title=\CONTEXT\ Language Macros,
%D       subtitle=Labels,
%D         author=Hans Hagen / Tobias Burnus,
%D           date=\currentdate,
%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\unprotect

%C The UPPERCASE variants are obsolete as we can now use \WORD
%C in an non-interfering way.

%D In this module we deal with language dependant labels and
%D prefixes, like in {\em Figure~12} and {\em Chapter 1}. In
%D this file we set the default values. Users can easily
%D overrule these.
%D
%D This module is dedicated to the grandfather of Tobias
%D Burnus, who's extensive languages oriented library helped us
%D a lot in finding the right translations. All those labels
%D are collected in files that reflect their common ancestor.
%D
%D Not all languages can be satisfied with the labeling
%D mechanism as provided here. Chinese for instance put a label
%D in front as well as after a part number. This is why the
%D current implementation of labels supports two labels too.

\ifdefined\simplifiedcommands \else \newtoks\simplifiedcommands \fi
\ifdefined\Word               \else \let\Word\relax             \fi

%D \macros
%D   {setupheadtext, setuplabeltext}
%D
%D First we present some macros that deal with what we will
%D call head and label texts. Such texts are defines by:
%D
%D \showsetup{setupheadtext}
%D \showsetup{setuplabeltext}
%D
%D A regular \CONTEXT\ stores some 1500 labels at most.
%D
%D These commands accept all kind of inputs:
%D
%D \starttyping
%D \setuplabeltext [language] [labellabel=text]
%D \setuplabeltext [language] [labellabel=text,labellabel=text,...]
%D \setuplabeltext            [labellabel=text]
%D \setuplabeltext            [labellabel=text,labellabel=text,...]
%D \stoptyping
%D
%D The last two cases concern the current language.

\def\definelabelclass
  {\dodoubleempty\dodefinelabelclass}

\def\dodefinelabelclass[#1][#2]%
  {\normalexpanded
     {\noexpand\dododefinelabelclass
        {#1}%
        {\ifsecondargument#2\else\zerocount\fi}%
        \expandafter\noexpand\csname   dogetupsome#1text\endcsname
        \expandafter\noexpand\csname          #1language\endcsname
        \expandafter\noexpand\csname dodogetupsome#1text\endcsname
        \expandafter\noexpand\csname          left#1text\endcsname
        \expandafter\noexpand\csname         right#1text\endcsname
        \expandafter\noexpand\csname             #1texts\endcsname
        \expandafter\noexpand\csname              #1text\endcsname}}

\def\dododefinelabelclass#1#2#3#4#5#6#7#8#9%
  {\setuvalue{setup#1text}{\protecttextprefixes#2\def\currenttextprefixclass{#1}\dodoubleempty\dosetupsometextprefix}%
   \setuvalue{preset#1text}{\protecttextprefixes1\def\currenttextprefixclass{#1}\dodoubleempty\dosetupsometextprefix}%
   \def#4{\reallanguagetag{\defaultlanguage\currentmainlanguage}}%
   \ifnum#2=\plustwo
     \def#3{#5#4}%
     \def#5##1##2% ##1=language
       {\ifcsname\??ml:#1:##1:##2\endcsname
          \csname\??ml:#1:##1:##2\endcsname
        \else\ifcsname\??la#4\s!default\endcsname
          \expandafter#5\csname\??la#4\s!default\endcsname{##2}%
        \else\ifcsname\??ml:#1:##2\endcsname
          \csname\??ml:#1:##2\endcsname
        \else\ifcsname\??ml:#1:\s!en:##2\endcsname
          \csname\??ml:#1:\s!en:##2\endcsname
        \else
          ##2%
        \fi\fi\fi\fi}%
     \let#6\gobbleoneargument
     \let#7\gobbleoneargument
     \let#8\gobbletwoarguments
     \let#9#3%
   \else
     \unexpanded\def#3{#5#4}%
     \unexpanded\def#5##1##2%
       {\ifcsname\??ml:#1:##1:##2\endcsname
          \expandafter\let\expandafter\thetextprefix\csname\??ml:#1:##1:##2\endcsname
        \else\ifcsname\??la#4\s!default\endcsname
          \expandafter#5\csname\??la#4\s!default\endcsname{##2}%
        \else\ifcsname\??ml:#1:##2\endcsname
          \expandafter\let\expandafter\thetextprefix\csname\??ml:#1:##2\endcsname
        \else\ifcsname\??ml:#1:\s!en:##2\endcsname
          \expandafter\let\expandafter\thetextprefix\csname\??ml:#1:\s!en:##2\endcsname
        \else
          \let\thetextprefix\dummytextprefix
        \fi\fi\fi\fi}%
     \unexpanded\def#6##1{#3{##1}\expandafter\flushleftlabelclass \thetextprefix}%
     \unexpanded\def#7##1{#3{##1}\expandafter\flushrightlabelclass\thetextprefix}%
     \unexpanded\def#8##1{#3{##1}\expandafter\flushbothlabelclass \thetextprefix}% #2
     \unexpanded\def#9##1{#3{##1}\expandafter\flushleftlabelclass \thetextprefix}%
   \fi
   \appendtoks
     \let#6\firstofoneargument % to be checked
     \let#7\firstofoneargument % to be checked
     \let#8\firstofoneargument % to be checked
     \let#9\firstofoneargument % to be checked
   \to \simplifiedcommands
  }

\let\flushleftlabelclass \firstoftwoarguments
\let\flushrightlabelclass\secondoftwoarguments
\def\flushbothlabelclass #1#2#3{#1#3#2}
\def\dummytextprefix     {\empty\empty}

%D \macros
%D   {headtext,
%D    labeltext, leftlabeltext, rightlabeltext, labeltexts,
%D    LABELTEXT, LEFTLABELTEXT, RIGHTLABELTEXT, LABELTEXTS}
%D
%D Once defined, head and label texts can be called upon using:
%D
%D \showsetup{headtext}
%D \showsetup{labeltext}
%D
%D The latter one has an upcased alternative \type{\LABELTEXT}.
%D
%D \macros
%D   {presetheadtext,presetlabeltext}
%D
%D These macros enable us to automatically define head and label
%D texts without replacing predefined ones. They are internal macros.

\definelabelclass [head]      [0]
\definelabelclass [label]     [0]
\definelabelclass [mathlabel] [0]
\definelabelclass [taglabel]  [2]

\appendtoks \let\labellanguage\currentlanguage \to \everycurrentdate

\newconstant\protecttextprefixes

\let\currenttextprefixtag  \s!unknown
\let\currenttextprefixclass\s!unknown

\def\dosetupsometextprefix[#1][#2]%
  {\ifsecondargument
     \edef\currenttextprefixtag{\reallanguagetag{#1}}%
     \processcommalist[#2]\dodosetupsometextprefix
   \else
     \edef\currenttextprefixtag{\reallanguagetag\currentmainlanguage}%
     \processcommalist[#1]\dodosetupsometextprefix
   \fi}

\def\dodosetupsometextprefix#1%
  {\dododosetupsometextprefix[#1]}

\def\dododosetupsometextprefix[#1=#2]%
  {\doassignsometextprefix{#1}[#2,,]}

\def\doassignsometextprefix#1%
  {\ifcase\protecttextprefixes
     % no checking
     \expandafter\doassignsometextprefixyes
   \or
     % checking
     \ifcsname\??ml:\currenttextprefixclass:\currenttextprefixtag:#1\endcsname
       \expandafter\expandafter\expandafter\doassignsometextprefixnop
     \else
       \expandafter\expandafter\expandafter\doassignsometextprefixyes
     \fi
   \or
     % simple assignment (a bit overkill but it fits in the whole)
     \expandafter\doassignsometextprefixdumb
   \fi{#1}}

\def\doassignsometextprefixyes#1[#2,#3,#4]%
  {\edef\!!stringa{#2}%
   \edef\!!stringb{#3}%
   \ifx\!!stringb\empty
     \ifx\!!stringa\empty
       \expandafter\def\csname\??ml:\currenttextprefixclass:\currenttextprefixtag:#1\endcsname{\empty\empty}%
     \else
       \expandafter\def\csname\??ml:\currenttextprefixclass:\currenttextprefixtag:#1\endcsname{{#2}\empty}%
     \fi
   \else
     \expandafter\def\csname\??ml:\currenttextprefixclass:\currenttextprefixtag:#1\endcsname{{#2}{#3}}%
   \fi}

\def\doassignsometextprefixnop#1[#2]%
  {}

\def\doassignsometextprefixdumb#1[#2,#3]%
  {\expandafter\def\csname\??ml:\currenttextprefixclass:\currenttextprefixtag:#1\endcsname{#2}}

%D \macros
%D   {translate}
%D
%D Sometimes macros contain language specific words that are to
%D be typeset. Such macros can be made (more) language
%D independant by using:
%D
%D \showsetup{translate}
%D
%D like for instance:
%D
%D \starttyping
%D \translate[en=something,nl=iets]
%D \stoptyping
%D
%D which expands to {\em something} or {\em iets}, depending on
%D de current language.

\def\dotranslate[#1]%
  {\getparameters[\??lg][#1]%
   \ifcsname\??lg\currentlanguage\endcsname
     \csname\??lg\currentlanguage\endcsname
   \else\ifcsname\??lg\s!en\endcsname
     \csname\??lg\s!en\endcsname
   \else
     [translation #1]%
   \fi\fi}

\unexpanded\def\translate
  {\dosingleempty\dotranslate}

%D When used without argument, the last defined values are
%D used. This enables repetitive use like
%D
%D \starttyping
%D \en \translate\ means \nl \translate
%D \stoptyping

%D \macros
%D   {assigntranslation}
%D
%D This macro is a system macro, and can be used to assign a
%D translation to a macro. Its form is:
%D
%D \starttyping
%D \assigntranslation[en=something,nl=iets]\to\command
%D \stoptyping

\def\assigntranslation[#1]\to#2%
  {\getparameters[\??lg][#1]%
   \edef#2{\csname\??lg\currentlanguage\endcsname}}

\protect \endinput