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@@ -1,1148 +1,1149 @@
-%D \module
-%D [ file=mult-ini,
-%D version=1996.06.01,
-%D title=\CONTEXT\ Multilingual Macros,
-%D subtitle=Initialization,
-%D author=Hans Hagen,
-%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. Non||commercial use is
-%C granted.
-
-%D This module implements the multi||lingual interface to
-%D \CONTEXT. These capabilities concern messages, commands and
-%D parameters.
-
-\writestatus{loading}{Context Multilingual Macros / Initialization}
-
-\unprotect
-
-%D \macros
-%D [constanten,variabelen,commandos]
-%D {v!,c!,s!,e!,m!,l!,r!,f!,p!,x!,y!}
-%D {}
-%D
-%D In the system modules we introduced some prefixed constants,
-%D variables (both macros) and registers. Apart from a
-%D tremendous saving in terms of memory and a gain in speed we
-%D use from now on prefixes when possible for just another
-%D reason: consistency and multi||linguality. Systematically
-%D using prefixed macros enables us to implement a
-%D multi||lingual user interface. Redefining these next set of
-%D prefixes therefore can have desastrous results.
-%D
-%D \startregelcorrectie
-%D \starttabel[|c|c|c|]
-%D \HL
-%D \NC \bf prefix \NC \bf meaning \NC \bf application \NC\SR
-%D \HL
-%D \NC \type{\v!prefix!} \NC v! \NC variable \NC\FR
-%D \NC \type{\c!prefix!} \NC c! \NC constant \NC\MR
-%D \NC \type{\s!prefix!} \NC s! \NC system \NC\MR
-%D \NC \type{\e!prefix!} \NC e! \NC element \NC\MR
-%D \NC \type{\m!prefix!} \NC m! \NC message \NC\MR
-%D \NC \type{\l!prefix!} \NC l! \NC language \NC\MR
-%D \NC \type{\r!prefix!} \NC r! \NC reference \NC\MR
-%D \NC \type{\f!prefix!} \NC f! \NC file \NC\MR
-%D \NC \type{\p!prefix!} \NC p! \NC procedure \NC\MR
-%D \NC \type{\x!prefix!} \NC x! \NC setup constant \NC\MR
-%D \NC \type{\y!prefix!} \NC y! \NC setup variable \NC\LR
-%D \HL
-%D \stoptabel
-%D \stopregelcorrectie
-%D
-%D In the single||lingual version we used \type{!}, \type{!!},
-%D \type{!!!} and \type{!!!!}.
-
-\def\v!prefix!{v!} \def\c!prefix!{c!} \def\s!prefix!{s!}
-\def\e!prefix!{e!} \def\m!prefix!{m!} \def\r!prefix!{r!}
-\def\f!prefix!{f!} \def\p!prefix!{p!} \def\x!prefix!{x!}
-\def\y!prefix!{y!} \def\l!prefix!{l!}
-
-%D \macros
-%D [constants,variables,commands]
-%D {@@,??}
-%D {}
-%D
-%D Variables generated by the system can be recognized on their
-%D prefix \type{@@}. They are composed of a command (class)
-%D specific tag, which can be recognized on \type{??}, and a
-%D system constant, which has the prefix \type{c!}. We'll se
-%D some more of this.
-
-\def\??prefix {??}
-\def\@@prefix {@@}
-
-%D Just to be complete we repeat some of the already defined
-%D system constants here. Maybe their prefix \type{\s!} now
-%D falls into place.
-
-\def\s!next {next} \def\s!default {default}
-\def\s!dummy {dummy} \def\s!unknown {unknown}
-
-\def\s!do {do} \def\s!dodo {dodo}
-
-\def\s!complex {complex} \def\s!start {start}
-\def\s!simple {simple} \def\s!stop {stop}
-
-\def\!!width {width} \def\!!plus {plus}
-\def\!!height {height} \def\!!minus {minus}
-\def\!!depth {depth}
-
-%D \macros
-%D {defineinterfaceconstant,
-%D defineinterfacevariable,
-%D defineinterfaceelement,
-%D definesystemvariable,
-%D definesystemconstant,
-%D definemessageconstant,
-%D definereferenceconstant,
-%D definefileconstant}
-%D {}
-%D
-%D The first part of this module is dedicated to dealing with
-%D multi||lingual constants and variables. When \CONTEXT\ grew
-%D bigger and bigger in terms of bytes and used string space,
-%D we switched to predefined constants. At the cost of more
-%D hash table entries, the macros not only becase more compact,
-%D they became much faster too. Maybe an even bigger advantage
-%D was that mispelling could no longer lead to problems. Even a
-%D multi||lingual interface became possible.
-%D
-%D Constants --- we'll introduce the concept of variables later
-%D on --- are preceded by a type specific prefix, followed by a
-%D \type{!}. To force consistency, we provide a few commands
-%D for defining such constants.
-%D
-%D \starttypen
-%D \defineinterfaceconstant {name} {meaning}
-%D \defineinterfacevariable {name} {meaning}
-%D \defineinterfaceelement {name} {meaning}
-%D \stoptypen
-%D
-%D Which is the same as:
-%D
-%D \starttypen
-%D \def\c!name{meaning}
-%D \def\v!name{meaning}
-%D \def\e!name{meaning}
-%D \stoptypen
-
-\def\defineinterfaceconstant #1#2{\setvalue{\c!prefix!#1}{#2}}
-\def\defineinterfacevariable #1#2{\setvalue{\v!prefix!#1}{#2}}
-\def\defineinterfaceelement #1#2{\setvalue{\e!prefix!#1}{#2}}
-
-%D Next come some interface independant constants:
-%D
-%D \starttypen
-%D \definereferenceconstant {name} {meaning}
-%D \definefileconstant {name} {meaning}
-%D \stoptypen
-
-\def\definereferenceconstant #1#2{\setvalue{\r!prefix!#1}{#2}}
-\def\definefileconstant #1#2{\setvalue{\f!prefix!#1}{#2}}
-
-%D And finaly we have the one argument, space saving constants
-%D
-%D \starttypen
-%D \definesystemconstant {name}
-%D \definemessageconstant {name}
-%D \stoptypen
-
-\def\definesystemconstant #1{\setvalue{\s!prefix!#1}{#1}}
-\def\definemessageconstant #1{\setvalue{\m!prefix!#1}{#1}}
-
-%D In a parameter driven system, some parameters are shared
-%D by more system components. In \CONTEXT\ we can distinguish
-%D parameters by a unique prefix. Such a prefix is defined
-%D with:
-%D
-%D \starttypen
-%D \definesystemvariable {name}
-%D \stoptypen
-
-\def\definesystemvariable #1{\setevalue{\??prefix#1}{\@@prefix#1}}
-
-%D \macros
-%D {selectinterface,
-%D defaultinterface, currentinterface, currentresponses}
-%D {}
-%D
-%D With \type{\selectinterface} we specify the language we are
-%D going to use. The system asks for the language wanted, and
-%D defaults to \type{\currentinterface} when we just give
-%D \type{enter}. By default the message system uses the
-%D current interface language, but \type{\currentresponses}
-%D can specify another language too.
-%D
-%D Because we want to generate formats directly too, we do
-%D not ask for interface specifications when these are already
-%D defined (like in cont-nl.tex and alike).
-
-\ifx\defaultinterface\undefined
-
- \def\defaultinterface{dutch}
-
- \def\selectinterface%
- {\def\docommando##1##2%
- {\bgroup
- \endlinechar=-1
- \global\read16 to ##1
- \egroup
- \doif{\currentinterface}{}{\let##1=##2}%
- \doifundefined{\s!prefix!##1}{\let##1=##2}}%
- \docommando\currentinterface\defaultinterface
- \writestatus{interface}{defining \currentinterface\space interface}%
- \writeline
- \docommando\currentresponses\currentinterface
- \writestatus{interface}{using \currentresponses\space messages}%
- \writeline}
-
-\else
-
- \def\selectinterface%
- {\writestatus{interface}{defining \currentinterface\space interface}%
- \writeline
- \writestatus{interface}{using \currentresponses\space messages}%
- \writeline}
-
-\fi
-
-\ifx\currentinterface\undefined \let\currentinterface=\defaultinterface \fi
-\ifx\currentresponses\undefined \let\currentresponses=\defaultinterface \fi
-
-%D \macros
-%D {startinterface}
-%D {}
-%D
-%D Sometimes we want to define things only for specific
-%D interface languages. This can be done by means of the
-%D selector:
-%D
-%D \starttypen
-%D \startinterface language
-%D
-%D language specific definitions & commands
-%D
-%D \stopinterface
-%D \stoptypen
-
-%\long\def\startinterface #1 #2\stopinterface%
-% {\doifelse{#1}{\currentinterface}
-% {\long\def\next{#2}}
-% {\let\next=\relax}%
-% \next}
-
-\def\startinterface #1
- {\doifelse{#1}{\currentinterface}
- {\let\next=\relax}
- {\long\def\next##1\stopinterface{}}%
- \next}
-
-\let\stopinterface=\relax
-
-%D \macros
-%D {startmessages,
-%D getmessage,
-%D showmessage,
-%D makemessage}
-%D {}
-%D
-%D A package as large as \CONTEXT\ can hardly function without
-%D a decent message mechanism. Due to its multi||lingual
-%D interface, the message subsystem has to be multi||lingual
-%D too. A major drawback of this feature is that we have to
-%D code messages. As a result, the source becomes less self
-%D documented. On the other hand, consistency will improve.
-%D
-%D Because the overhead in terms of entries in the (already
-%D exhausted) hash table has to be minimal, messages are packed
-%D in libraries. We can extract a message from such a library
-%D in three ways:
-%D
-%D \starttypen
-%D \getmessage {library} {tag}
-%D \showmessage {library} {tag} {data}
-%D \makemessage {library} {tag} {data}
-%D \stoptypen
-%D
-%D The first command gets the message \type{tag} from the
-%D \type{library} specified. The other commands take an extra
-%D argument: a list of items to be inserted in the message
-%D text. While \type{\showmessage} shows the message at the
-%D terminal, the other commands generate the message as text.
-%D Before we explain the \type{data} argument, we give an
-%D example of a library.
-%D
-%D \starttypen
-%D \startmessages english library: alfa
-%D title: something
-%D 1: first message
-%D 2: second (--) message --
-%D \stopmessages
-%D \stoptypen
-%D
-%D The first message is a simple one and can be shown with:
-%D
-%D \starttypen
-%D \showmessage {alfa} {1} {}
-%D \stoptypen
-%D
-%D The second message on the other hand needs some extra data:
-%D
-%D \starttypen
-%D \showmessage {alfa} {2} {and last,to you}
-%D \stoptypen
-%D
-%D This message is shown as:
-%D
-%D \starttypen
-%D something : second (and last) message to you
-%D \stoptypen
-%D
-%D As we can see, the title entry is shown with the message.
-%D The data fields are comma separated and are specified in the
-%D message text by \type{--}.
-%D
-%D It is not required to define all messages in a library at
-%D once. We can add messages to a library in the following way:
-%D
-%D \starttypen
-%D \startmessages english library: alfa
-%D 10: tenth message
-%D \stopmessages
-%D \stoptypen
-%D
-%D Because such definitions can take place in different
-%D modules, the system gives a warning when a tag occurs more
-%D than once. The first occurrence takes preference over later
-%D ones, so we had better use a save offset, as shown in the
-%D example. As we can see, the title field is specified only
-%D the first time!
-%D
-%D Because we want to check for duplicate tags, the macros
-%D are a bit more complicated than neccessary. The \NEWLINE\
-%D token is used as message separator.
-
-\def\findinterfacemessage#1#2%
- {\def#2{}%
- \def\dofindinterfacemessage##1 #1: ##2\relax##3\end%
- {\def#2{##2}}%
- \edef\!!stringa{\getvalue{@@ms\currentmessagelibrary} #1: \relax}%
- \expandafter\dofindinterfacemessage\!!stringa\end}
-
-\def\composemessagetext#1--#2--#3--#4--#5--#6\\%
- {\def\docomposemessagetext##1,##2,##3,##4,##5,##6\\%
- {\edef\currentmessagetext{#1##1#2##2#3##3#4##4#5##5}}%
- \docomposemessagetext}
-
-\unexpanded\def\getmessage#1#2%
- {\def\currentmessagelibrary{#1}%
- \findinterfacemessage{#2}\currentmessagetext
- \currentmessagetext}
-
-\unexpanded\def\makemessage#1#2#3%
- {\def\currentmessagelibrary{#1}%
- \findinterfacemessage{#2}\currentmessagetext
- \@EA\composemessagetext\currentmessagetext----------\\#3,,,,,\\%
- \currentmessagetext}
-
-\def\showmessage#1#2#3%
- {\def\currentmessagelibrary{#1}%
- \findinterfacemessage{#2}\currentmessagetext
- \findinterfacemessage{title}\currentmessagetitle
- \doifelse{\currentmessagetext}{}
- {\def\currentmessagetext{<unknown message #2>}}
- {\@EA\composemessagetext\currentmessagetext----------\\#3,,,,,\\}%
- \@EA\writestatus\@EA{\currentmessagetitle}{\currentmessagetext}}
-
-\def\doaddinterfacemessage#1#2%
- {\findinterfacemessage{#1}\currentmessagetext
- \doifelse{\currentmessagetext}{}
- {\setxvalue{@@ms\currentmessagelibrary}%
- {\getvalue{@@ms\currentmessagelibrary} #1: #2\relax}}
- {\debuggerinfotrue % we consider this an important error
- \debuggerinfo
- {message}
- {duplicate tag #1
- in library \currentmessagelibrary\space
- of interface \currentresponses}}%
- \futurelet\next\getinterfacemessage}
-
-\bgroup
-\obeylines
-\gdef\addinterfacemessage#1: #2
- {\doaddinterfacemessage{#1}{#2}}%
-\egroup
-
-\def\getinterfacemessage%
- {\ifx\next\stopmessages
- \def\next##1{\egroup}%
- \else
- \let\next=\addinterfacemessage
- \fi
- \next}
-
-\gdef\startmessages #1 library: #2
- {\bgroup
- \obeylines
- \doifinsetelse{#1}{\currentresponses,all}
- {\def\next%
- {\def\currentmessagelibrary{#2}%
- \doifundefined{@@ms\currentmessagelibrary}
- {\setgvalue{@@ms\currentmessagelibrary}{}}%
- \futurelet\next\getinterfacemessage}}
- {\long\def\next##1\stopmessages{\egroup}}%
- \next}
-
-%D \macros
-%D {ifshowwarnings, ifshowmessages}
-%D
-%D Sometimes displaying message can slow down processing
-%D considerably. We therefore introduce warnings. Users can
-%D turn of warnings and messages by saying:
-%D
-%D \starttypen
-%D \showwarningstrue
-%D \showmessagestrue
-%D \stoptypen
-%D
-%D Turning off messages also turns off warnings, which is
-%D quote logical because they are less important.
-
-\newif\ifshowwarnings \showwarningstrue
-\newif\ifshowmessages \showmessagestrue
-
-\let\normalshowmessage=\showmessage
-
-\def\showwarning%
- {\ifshowwarnings
- \expandafter\showmessage
- \else
- \expandafter\gobblethreearguments
- \fi}
-
-\def\showmessage%
- {\ifshowmessages
- \expandafter\normalshowmessage
- \else
- \expandafter\gobblethreearguments
- \fi}
-
-%D \macros
-%D {dosetvalue,dosetevalue,docopyvalue,doresetvalue,
-%D dogetvalue}
-%D {}
-%D
-%D We already defined these auxiliary macros in the system
-%D modules. Starting with this module however, we have to take
-%D multi||linguality a bit more serious.
-%D
-%D First we show a well||defined alternative:
-%D
-%D \starttypen
-%D \def\dosetvalue#1#2#3%
-%D {\doifdefinedelse{\c!prefix!#2}
-%D {\setvalue{#1\getvalue{\c!prefix!#2}}{#3}}
-%D {\setvalue{#1#2}{#3}}}
-%D
-%D \def\docopyvalue#1#2#3%
-%D {\doifdefinedelse{\c!prefix!#3}
-%D {\setvalue{#1\getvalue{\c!prefix!#3}}%
-%D {\getvalue{#2\getvalue{\c!prefix!#3}}}}
-%D {\setvalue{#1#3}%
-%D {\getvalue{#2#3}}}}
-%D
-%D \def\dogetvalue#1#2%
-%D {\getvalue{#1\getvalue{\c!prefix!#2}}}
-%D \stoptypen
-%D
-%D These macros are called upon quite often and so we optimized
-%D them a bit.
-
-\def\dosetvalue#1#2#3%
- {\p!doifundefined{\c!prefix!#2}%
- \let\donottest=\doprocesstest
- \@EA\def\csname#1#2\endcsname{#3}%
- \else
- \let\donottest=\doprocesstest
- \@EA\def\csname#1\csname\c!prefix!#2\endcsname\endcsname{#3}%
- \fi}
-
-\def\dosetevalue#1#2#3%
- {\p!doifundefined{\c!prefix!#2}%
- \let\donottest=\doprocesstest
- \@EA\edef\csname#1#2\endcsname{#3}%
- \else
- \let\donottest=\doprocesstest
- \@EA\edef\csname#1\csname\c!prefix!#2\endcsname\endcsname{#3}%
- \fi}
-
-\def\docopyvalue#1#2#3%
- {\p!doifundefined{\c!prefix!#3}%
- \let\donottest=\doprocesstest
- \@EA\def\csname#1#3\endcsname%
- {\csname#2#3\endcsname}%
- \else
- \let\donottest=\doprocesstest
- \@EA\def\csname#1\csname\c!prefix!#3\endcsname\endcsname%
- {\csname#2\csname\c!prefix!#3\endcsname\endcsname}%
- \fi}
-
-\def\doresetvalue#1#2%
- {\dosetvalue{#1}{#2}{}}
-
-\def\dogetvalue#1#2%
- {\csname#1\csname\c!prefix!#2\endcsname\endcsname}
-
-%D Although maybe bot clearly visible, there is a
-%D considerable profit in further optimalization. By expanding
-%D the embedded \type{\csname} we can reduce the format file
-%D by about 5\% (60~KB out of 1.9~MB).
-
-\def\docopyvalue#1#2#3%
- {\p!doifundefined{\c!prefix!#3}%
- \let\donottest=\doprocesstest
- \@EA\@EA\@EA\def\@EA\csname\@EA#1\@EA#3\@EA\endcsname
- \@EA{\csname#2#3\endcsname}%
- \else
- \let\donottest=\doprocesstest
- \@EA\@EA\@EA\def\@EA
- \csname
- \@EA#1\@EA\csname\@EA\c!prefix!\@EA#3\@EA\endcsname\@EA
- \endcsname
- \@EA{\csname#2\csname\c!prefix!#3\endcsname\endcsname}%
- \fi}
-
-%D We take this opportunity of redefining to adapt an
-%D assignment macro. The change has to do with the fact that the
-%D generated error message must be multi||lingual. We can not
-%D define the message yet, because we still have to select the
-%D interface language.
-
-%\def\p!doassign#1[#2][#3=#4=#5]%
-% {\let\donottest=\dontprocesstest
-% \edef\!!stringa{#5}%
-% \edef\!!stringb{\relax}%
-% \let\donottest=\doprocesstest
-% \ifx\!!stringa\!!stringb
-% \showmessage{check}{1}{#3,\the\inputlineno}%
-% \else
-% #1{#2}{#3}{#4}%
-% \fi}
-
-\def\p!doassign#1[#2][#3=#4=#5]%
- {\ifx\empty#3\else % and definitely not \ifx#3\empty
- \ifx\relax#5%
- \showmessage{check}{1}{#3,\the\inputlineno}%
- \else
- #1{#2}{#3}{#4}%
- \fi
- \fi}
-
-\def\dogetargument#1#2#3#4%
- {\doifnextcharelse{#1}
- {\let\expectedarguments=\noexpectedarguments
- #3\dodogetargument}
- {\ifnum\expectedarguments>\noexpectedarguments
- \showmessage{check}{2}{\the\expectedarguments,\the\inputlineno}%
- \fi
- \let\expectedarguments=\noexpectedarguments
- #4\dodogetargument#1#2}}
-
-\def\dogetgroupargument#1#2%
- {\def\nextnextargument%
- {\ifx\nextargument\bgroup
- \let\expectedarguments=\noexpectedarguments
- \def\nextargument{#1\dodogetargument}%
- %\else\ifx\nextargument\lineending % this can be an option
- % \def\nextargument{\bgroup\def\\ {\egroup\dogetgroupargument#1#2}\\}%
- %\else\ifx\nextargument\blankspace % but may never be default
- % \def\nextargument{\bgroup\def\\ {\egroup\dogetgroupargument#1#2}\\}%
- \else
- \ifnum\expectedarguments>\noexpectedarguments
- \showmessage{check}{2}{\the\expectedarguments,\the\inputlineno}%
- \fi
- \let\expectedarguments=\noexpectedarguments
- \def\nextargument{#2\dodogetargument{}}%
- \fi%\fi\fi % so let's get rid of it
- \nextargument}%
- \futurelet\nextargument\nextnextargument}
-
-\def\checkdefined#1#2#3%
- {\doifdefined{#3}
- {\showmessage{check}{3}{#2,#3}}}
-
-%D \CONTEXT\ is a parameter driven package. This means that
-%D users instruct the system by means of variables, values and
-%D keywords. These instructions take the form:
-%D
-%D \starttypen
-%D \setupsomething[some variable=some value, another one=a keyword]
-%D \stoptypen
-%D
-%D or by keyword only:
-%D
-%D \starttypen
-%D \dosomething[this way, that way, no way]
-%D \stoptypen
-%D
-%D Because the same variables can occur in more than one setup
-%D command, we have to be able to distinguish them. This is
-%D achieved by assigning them a unique prefix.
-%D
-%D Imagine a setup command for boxed text, that enables us to
-%D specify the height and width of the box. Behide the scenes
-%D the command
-%D
-%D \starttypen
-%D \setupbox [width=12cm, height=3cm]
-%D \stoptypen
-%D
-%D results in something like
-%D
-%D \starttypen
-%D \<box><width> {12cm}
-%D \<box><height> {3cm}
-%D \stoptypen
-%D
-%D while a similar command for specifying the page dimensions
-%D of an \kap{A4} page results in:
-%D
-%D \starttypen
-%D \<page><width> {21.0cm}
-%D \<page><height> {27.9cm}
-%D \stoptypen
-%D
-%D The prefixes \type{<box>} and \type{<page>} are hidden from
-%D users and can therefore be language independant. Variables
-%D on the other hand, differ for each language:
-%D
-%D \starttypen
-%D \<box><color> {<blue>}
-%D \<box><kleur> {<blauw>}
-%D \<box><couleur> {<blue>}
-%D \stoptypen
-%D
-%D In this example we can see that the assigned values or
-%D keywords are language dependant too. This will be a
-%D complication when defining multi||lingual setup files.
-%D
-%D A third phenomena is that variables and values can have a
-%D similar meaning.
-%D
-%D \starttypen
-%D \<pagenumber><location> {<left>}
-%D \<skip><left> {12cm}
-%D \stoptypen
-%D
-%D A (minor) complication is that where in english we use
-%D \type{<left>}, in dutch we find both \type{<links>} and
-%D \type{<linker>}. This means that when we use some sort of
-%D translation table, we have to distinguish between the
-%D variables at the left side and the fixed values at the
-%D right.
-%D
-%D The same goes for commands that are composed of different
-%D user supplied and/or language specific elements. In english
-%D we can use:
-%D
-%D \starttypen
-%D \<empty><figure>
-%D \<empty><intermezzo>
-%D \stoptypen
-%D
-%D But in dutch we have the following:
-%D
-%D \starttypen
-%D \<lege><figuur>
-%D \<leeg><intermezzo>
-%D \stoptypen
-%D
-%D These subtle differences automatically lead to a solution
-%D where variables, values, elements and other components have
-%D a similar logical name (used in macro's) but a different
-%D meaning (supplied by the user).
-%D
-%D Our solution is one in which the whole system is programmed
-%D in terms of identifiers with language specific meanings. In
-%D such an implementation, each fixed variable is available as:
-%D
-%D \starttypen
-%D \<prefix><variable>
-%D \stoptypen
-%D
-%D This means that for instance:
-%D
-%D \starttypen
-%D \setupbox[width=12cm]
-%D \stoptypen
-%D
-%D expands to something like:
-%D
-%D \starttypen
-%D \def\boxwidth{12cm}
-%D \stoptypen
-%D
-%D because we don't want to recode the source, a setup command
-%D in another language has to expand to this variable, so:
-%D
-%D \starttypen
-%D \stelblokin[breedte=12cm]
-%D \stoptypen
-%D
-%D has to result in the definition of \type{\boxwidth} too.
-%D This method enables us to build compact, fast and readable
-%D code.
-%D
-%D An alternative method, which we considered using, uses a
-%D more indirect way. In this case, both calls generate a
-%D different variable:
-%D
-%D \starttypen
-%D \def\boxwidth {12cm}
-%D \def\boxbreedte {12cm}
-%D \stoptypen
-%D
-%D And because we don't want to recode those megabytes of
-%D already developed code, this variable has to be called with
-%D something like:
-%D
-%D \starttypen
-%D \valueof\box\width
-%D \stoptypen
-%D
-%D where \type{\valueof} takes care of the translation of
-%D \type{width} or \type{breedte} to \type{width} and
-%D combining this with \type{box} to \type{\boxwidth}.
-%D
-%D One advantage of this other scheme is that, within certain
-%D limits, we can implement an interface that can be switched
-%D to another language at will, while the current approach
-%D fixes the interface at startup. There are, by the way,
-%D other reasons too for not choosing this scheme. Switching
-%D user generated commands is for instance impossible and a
-%D dual interface would therefore give a strange mix of
-%D languages.
-%D
-%D Now let's work out the first scheme. Although the left hand
-%D of the assignment is a variable from the users point of
-%D view, it is a constant in terms of the system. Both
-%D \type{width} and \type{breedte} expand to \type{width}
-%D because in the source we only encounter \type{width}. Such
-%D system constants are presented as
-%D
-%D \starttypen
-%D \c!width
-%D \stoptypen
-%D
-%D This constant is always equivalent to \type{width}. As we
-%D can see, we use \type{c!} to mark this one as constant. Its
-%D dutch counterpart is:
-%D
-%D \starttypen
-%D \c!breedte
-%D \stoptypen
-%D
-%D When we interpret a setup command each variable is
-%D translated to it's \type{c!} counterpart. This means that
-%D \type{breedte} and \type{width} expand to \type{\c!breedte}
-%D and \type{\c!width} which both expand to \type{width}. That
-%D way user variables become system constants.
-%D
-%D The interpretation is done by means of a general setup
-%D command \type{\getparameters} that we introduced in the
-%D system module. Let us define some simple setup command:
-%D
-%D \starttypen
-%D \def\setupbox[#1]%
-%D {\getparameters[\??bx][#1]}
-%D \stoptypen
-%D
-%D This command can be used as:
-%D
-%D \starttypen
-%D \setupbox [width=3cm, height=1cm]
-%D \stoptypen
-%D
-%D Afterwards we have two variables \type{\@@bxwidth} and
-%D \type{\@@bxheight} which have the values \type{3cm} and
-%D \type{1cm} assigned. These variables are a combinatiom of
-%D the setup prefix \type{\??bx}, which expands to \type{@@bx}
-%D and the translated user supplied variables \type{width} and
-%D \type{height} or \type{breedte} and \type{hoogte},
-%D depending on the actual language. In dutch we just say:
-%D
-%D \starttypen
-%D \stelblokin [breedte=3cm, hoogte=1cm]
-%D \stoptypen
-%D
-%D and get ourselves \type{\@@bxwidth} and \type{\@@bxheight}
-%D too. In the source of \CONTEXT, we can recognize constants
-%D and variables on their leading \type{c!}, \type{v!} etc.,
-%D prefixes on \type{??} and composed variables on \type{@@}.
-%D
-%D We already saw that user supplied keywords need some
-%D special treatment too. This time we don't translate the
-%D keyword, but instead use in the source a variable which
-%D meaning depends on the interface language.
-%D
-%D \starttypen
-%D \v!left
-%D \stoptypen
-%D
-%D Which can be used in macro's like:
-%D
-%D \starttypen
-%D \processaction
-%D [\@@bxlocation]
-%D [ \v!left=>\dosomethingontheleft,
-%D \v!middle=>\dosomthinginthemiddle,
-%D \v!right=>\dosomethingontheright]
-%D \stoptypen
-%D
-%D Because variables like \type{\@@bxlocation} can have a lot
-%D of meanings, including tricky expandable tokens, we cannot
-%D translate this meaning when we compare. This means that
-%D \type{\@@bxlocation} can be \type{left} of \type{links} of
-%D whatever meaning suits the language. But because
-%D \type{\v!left} also has a meaning that suits the language,
-%D we are able to compare.
-%D
-%D Although we know it sounds confusing we want to state two
-%D important characteristics of the interface as described:
-%D
-%D \startsmaller \em
-%D user variables become system constants
-%D \stopsmaller
-%D
-%D and
-%D
-%D \startsmaller \em
-%D user constants (keywords) become system variables
-%D \stopsmaller
-%D
-
-%D \macros
-%D {startconstants,startvariables}
-%D {}
-%D
-%D It's time to introduce the macro's that are responsible for
-%D this translations process, but first we show how constants
-%D and variables are defined. We only show two languages and
-%D a few words.
-%D
-%D \starttypen
-%D \startconstants english dutch
-%D
-%D width: width breedte
-%D height: height hoogte
-%D
-%D \stopconstants
-%D \stoptypen
-%D
-%D Keep in mind that what users see as variables, are constants
-%D for the system.
-%D
-%D \starttypen
-%D \startvariables english dutch
-%D
-%D location: left links
-%D text: text tekst
-%D
-%D \stopvariables
-%D \stoptypen
-%D
-%D The macro's responsible for interpreting these setups are
-%D shared. They take care of empty lines and permit a more or
-%D less free format. All setups accept the keyword \type{all}
-%D which equals every language.
-
-\def\nointerfaceobject{-}
-
-\def\startinterfaceobjects#1#2%
- {\!!counta=1
- \let\dogetinterfaceobject=\dogetinterfacetemplate
- \let\dowithinterfaceelement=#1%
- \def\dodogetinterfaceobjects%
- {\ifx\next#2%
- \def\next####1%
- {}%
- \else\ifx\next\par
- \long\def\next####1%
- {\dogetinterfaceobjects}%
- \else\ifx\next\empty
- \def\next####1%
- {\dogetinterfaceobjects}%
- \else
- \def\next####1 %
- {\dogetinterfaceobject[####1:\relax]%
- \dogetinterfaceobjects}%
- \fi\fi\fi
- \next}%
- \def\dogetinterfaceobjects%
- {\futurelet\next\dodogetinterfaceobjects}%
- \dogetinterfaceobjects}
-
-\def\dogetinterfacetemplate[#1:#2]%
- {\doifinsetelse{#1}{\currentinterface,all}
- {\let\dogetinterfaceobject=\doskipinterfaceobject}
- {\advance\!!counta by 1\relax}}
-
-\def\doskipinterfaceobject[#1:#2#3]%
- {\if#2:%
- \let\dogetinterfaceobject=\dogetinterfaceelement
- \dogetinterfaceobject[#1:#2#3]%
- \fi}
-
-\def\dogetinterfaceelement[#1:#2#3]%
- {\ifx#2:%
- \!!countb=0
- \def\!!stringa{#1}%
- \else
- \advance\!!countb by 1
- \ifnum\!!countb=\!!counta
- \@EA\dowithinterfaceelement\@EA{\!!stringa}{#1}%
- \let\dogetinterfaceobject=\doskipinterfaceobject
- \fi
- \fi}
-
-%D The constants and variables are defined as described. When
-%D \type{\interfacetranslation} is \type{true}, we also
-%D generate a reverse translation. Because we don't want to put
-%D too big a burden on \TEX's hash table, this is no default
-%D behavior. Reverse translation is used in the commands that
-%D generate the quick reference cards. We are going to define
-%D the real \CONTEXT\ commands in an abstract way and generate
-%D those reference cards for each language without further
-%D interference.
-
-\def\setinterfaceconstant#1#2%
- {\setvalue{\c!prefix!#1}{#1}%
- \doifelse{#2}{\nointerfaceobject}
- {\debuggerinfo{constant}{#1 defined as #1 by default}}
- {\debuggerinfo{constant}{#1 defined as #2}%
- \ifinterfacetranslation
- \setvalue{\x!prefix!#1}{#2}%
- \fi
- \setvalue{\c!prefix!#2}{#1}}}
-
-\def\setinterfacevariable#1#2%
- {\doifelse{#2}{\nointerfaceobject}
- {\debuggerinfo{variable}{#1 defined as #1 by default}%
- \setvalue{\v!prefix!#1}{#1}}
- {\debuggerinfo{variable}{#1 defined as #2}%
- \setvalue{\v!prefix!#1}{#2}}}
-
-\def\startvariables%
- {\startinterfaceobjects\setinterfacevariable\stopvariables}
-
-\def\startconstants%
- {\startinterfaceobjects\setinterfaceconstant\stopconstants}
-
-%D \macros
-%D {defineinterfaceconstant}
-%D
-%D Next we redefine a previously defined macro to take care of
-%D interface translation too. It's a bit redundant, because
-%D in thise situations we could use the c||version, but for
-%D documentation purposes the x||alternative comes in handy.
-
-\def\defineinterfaceconstant#1#2%
- {\setvalue{\c!prefix!#1}{#2}%
- \ifinterfacetranslation
- \setvalue{\x!prefix!#1}{#2}%
- \fi}
-
-%D \macros
-%D {startinterfacesetupconstant}
-%D {}
-%D
-%D The next command, \type{\startinterfacesetupconstant}, which
-%D behavior also depends on the boolean, is used for constants
-%D that are only needed in these quick reference macro's. The
-%D following, more efficient approach does not work here,
-%D because it sometimes generates spaces.
-%D
-%D \starttypen
-%D \def\setinterfacesetupconstant%
-%D {\ifinterfacetranslation
-%D \expandafter\setinterfaceconstant
-%D \fi}
-%D \stoptypen
-%D
-%D We therefore use the more redundant but robust method:
-
-\def\setinterfacesetupvariable#1#2%
- {\ifinterfacetranslation
- \doifelse{#2}{\nointerfaceobject}
- {\setvalue{\y!prefix!#1}{#1}}
- {\setvalue{\y!prefix!#1}{#2}}%
- \fi}
-
-\def\startsetupvariables%
- {\startinterfaceobjects\setinterfacesetupvariable\stopsetupvariables}
-
-%D \macros
-%D {startelements}
-%D {}
-%D
-%D Due to the object oriented nature of \CONTEXT, we also need
-%D to define the elements that are used to build commands:
-%D
-%D \starttypen
-%D \startelements english dutch
-%D
-%D beginvan: begin beginvan
-%D eindvan: end eindvan
-%D start: start start
-%D stop: stop stop
-%D
-%D \stopelements
-%D \stoptypen
-%D
-%D Such elements sometimes are the same in diferent
-%D languages, but mostly they differ. Things can get even
-%D confusing when we look at for instance the setup commands.
-%D In english we say \type{\setup<something>}, but in dutch we
-%D have: \type{\stel<iets>in}. Such split elements are no
-%D problem, because we just define two elements. When no second
-%D part is needed, we use a \type{-}:
-%D
-%D \starttypen
-%D \startelements english dutch
-%D
-%D setupa: setup stel
-%D setupb: - in
-%D
-%D \stopelements
-%D \stoptypen
-%D
-%D Element translation is realized by means of:
-
-\def\setinterfaceelement#1#2%
- {\doifelse{#2}{\nointerfaceobject}
- {\debuggerinfo{element}{#1 defined as <empty>}%
- \setvalue{\e!prefix!#1}{}}
- {\doifdefinedelse{\e!prefix!#1}
- {\doifnot{\getvalue{\e!prefix!#1}}{#2}
- {\debuggerinfo{element}{#1 redefined as #2}%
- \setvalue{\e!prefix!#1}{#2}}}
- {\debuggerinfo{element}{#1 defined as #2}%
- \setvalue{\e!prefix!#1}{#2}}}}
-
-\def\startelements%
- {\startinterfaceobjects\setinterfaceelement\stopelements}
-
-%D \macros
-%D {startcommands}
-%D {}
-%D
-%D The last setup has to do with the commands themselve.
-%D Commands are defined as:
-%D
-%D \starttypen
-%D \startcommands english dutch
-%D
-%D starttekst: starttext starttekst
-%D stoptekst: stoptext stoptekst
-%D omlijnd: framed omlijnd
-%D margewoord: marginword margewoord
-%D
-%D \stopcommands
-%D \stoptypen
-%D
-%D Here we also have to take care of the optional translation
-%D needed for reference cards.
-
-\def\setinterfacecommand#1#2%
- {\doifelse{#2}{\nointerfaceobject}
- {\debuggerinfo{command}{no link to #1}%
- \setinterfacesetupvariable{#1}{#1}}
- {\doifelse{#1}{#2}
- {\debuggerinfo{command}{#1 remains #1}}
- {\doifdefinedelse{#2}
- {\debuggerinfo{command}{core command #2 redefined as #1}}%
- {\debuggerinfo{command}{#2 defined as #1}}%
- \@EA\@EA\@EA\def\@EA\csname\@EA#2\@EA\endcsname
- \@EA{\csname#1\endcsname}}%
- \setinterfacesetupvariable{#1}{#2}}}
-
-\def\startcommands%
- {\startinterfaceobjects\setinterfacecommand\stopcommands}
-
-%D \macros
-%D {getinterfaceconstant, getinterfacevariable}
-%D {}
-%D
-%D Generating the interface translation macro's that are used
-%D in the reference lists, is enabled by setting the boolean:
-%D
-%D \starttypen
-%D \interfacetranslationtrue
-%D \stoptypen
-%D
-%D Keep in mind that enabling interfacetranslation costs a
-%D bit of hash space.
-
-\newif\ifinterfacetranslation
-
-\def\getinterfaceconstant#1%
- {\ifinterfacetranslation
- \doifdefinedelse{\x!prefix!#1}
- {\getvalue{\x!prefix!#1}}
- {#1}%
- \else
- #1%
- \fi}
-
-\def\getinterfacevariable#1%
- {\ifinterfacetranslation
- \doifdefinedelse{\y!prefix!#1}
- {\getvalue{\y!prefix!#1}}
- {#1}%
- \else
- #1%
- \fi}
-
-%D When a reference list is generated, one does not need to
-%D generate a new format. Just reloading the relevant
-%D definition files suits:
-%D
-%D \starttypen
-%D \interfacetranslationtrue
-%D \input mult-con
-%D \input mult-com
-%D \stoptypen
-
-%D \macros
-%D {interfaced}
-%D {}
-%D
-%D The setup commands translate the constants automatically.
-%D When we want to translate 'by hand' we can use the simple
-%D but effective command:
-%D
-%D \starttypen
-%D \interfaced {something}
-%D \stoptypen
-%D
-%D Giving \type{\interfaced{breedte}} results in \type{width}
-%D or, when not defined, in \type{breedte} itself.
-
-\def\interfaced#1%
- {\expandafter\ifx\csname\c!prefix!#1\endcsname\relax
- #1%
- \else
- \csname\c!prefix!#1\endcsname
- \fi}
-
-%D So much for the basic multi||lingual interface commands. The
-%D macro's can be enhanced with more testing facilities, but
-%D for the moment they suffice.
-
-\protect
-
-\endinput
+%D \module
+%D [ file=mult-ini,
+%D version=1996.06.01,
+%D title=\CONTEXT\ Multilingual Macros,
+%D subtitle=Initialization,
+%D author=Hans Hagen,
+%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. Non||commercial use is
+%C granted.
+
+%D This module implements the multi||lingual interface to
+%D \CONTEXT. These capabilities concern messages, commands and
+%D parameters.
+
+\writestatus{loading}{Context Multilingual Macros / Initialization}
+
+\unprotect
+
+%D \macros
+%D [constanten,variabelen,commandos]
+%D {v!,c!,s!,e!,m!,l!,r!,f!,p!,x!,y!}
+%D {}
+%D
+%D In the system modules we introduced some prefixed constants,
+%D variables (both macros) and registers. Apart from a
+%D tremendous saving in terms of memory and a gain in speed we
+%D use from now on prefixes when possible for just another
+%D reason: consistency and multi||linguality. Systematically
+%D using prefixed macros enables us to implement a
+%D multi||lingual user interface. Redefining these next set of
+%D prefixes therefore can have desastrous results.
+%D
+%D \startregelcorrectie
+%D \starttabel[|c|c|c|]
+%D \HL
+%D \NC \bf prefix \NC \bf meaning \NC \bf application \NC\SR
+%D \HL
+%D \NC \type{\v!prefix!} \NC v! \NC variable \NC\FR
+%D \NC \type{\c!prefix!} \NC c! \NC constant \NC\MR
+%D \NC \type{\s!prefix!} \NC s! \NC system \NC\MR
+%D \NC \type{\e!prefix!} \NC e! \NC element \NC\MR
+%D \NC \type{\m!prefix!} \NC m! \NC message \NC\MR
+%D \NC \type{\l!prefix!} \NC l! \NC language \NC\MR
+%D \NC \type{\r!prefix!} \NC r! \NC reference \NC\MR
+%D \NC \type{\f!prefix!} \NC f! \NC file \NC\MR
+%D \NC \type{\p!prefix!} \NC p! \NC procedure \NC\MR
+%D \NC \type{\x!prefix!} \NC x! \NC setup constant \NC\MR
+%D \NC \type{\y!prefix!} \NC y! \NC setup variable \NC\LR
+%D \HL
+%D \stoptabel
+%D \stopregelcorrectie
+%D
+%D In the single||lingual version we used \type{!}, \type{!!},
+%D \type{!!!} and \type{!!!!}.
+
+\def\v!prefix!{v!} \def\c!prefix!{c!} \def\s!prefix!{s!}
+\def\e!prefix!{e!} \def\m!prefix!{m!} \def\r!prefix!{r!}
+\def\f!prefix!{f!} \def\p!prefix!{p!} \def\x!prefix!{x!}
+\def\y!prefix!{y!} \def\l!prefix!{l!}
+
+%D \macros
+%D [constants,variables,commands]
+%D {@@,??}
+%D {}
+%D
+%D Variables generated by the system can be recognized on their
+%D prefix \type{@@}. They are composed of a command (class)
+%D specific tag, which can be recognized on \type{??}, and a
+%D system constant, which has the prefix \type{c!}. We'll se
+%D some more of this.
+
+\def\??prefix {??}
+\def\@@prefix {@@}
+
+%D Just to be complete we repeat some of the already defined
+%D system constants here. Maybe their prefix \type{\s!} now
+%D falls into place.
+
+\def\s!next {next} \def\s!default {default}
+\def\s!dummy {dummy} \def\s!unknown {unknown}
+
+\def\s!do {do} \def\s!dodo {dodo}
+
+\def\s!complex {complex} \def\s!start {start}
+\def\s!simple {simple} \def\s!stop {stop}
+
+\def\!!width {width} \def\!!plus {plus}
+\def\!!height {height} \def\!!minus {minus}
+\def\!!depth {depth}
+
+%D \macros
+%D {defineinterfaceconstant,
+%D defineinterfacevariable,
+%D defineinterfaceelement,
+%D definesystemvariable,
+%D definesystemconstant,
+%D definemessageconstant,
+%D definereferenceconstant,
+%D definefileconstant}
+%D {}
+%D
+%D The first part of this module is dedicated to dealing with
+%D multi||lingual constants and variables. When \CONTEXT\ grew
+%D bigger and bigger in terms of bytes and used string space,
+%D we switched to predefined constants. At the cost of more
+%D hash table entries, the macros not only becase more compact,
+%D they became much faster too. Maybe an even bigger advantage
+%D was that mispelling could no longer lead to problems. Even a
+%D multi||lingual interface became possible.
+%D
+%D Constants --- we'll introduce the concept of variables later
+%D on --- are preceded by a type specific prefix, followed by a
+%D \type{!}. To force consistency, we provide a few commands
+%D for defining such constants.
+%D
+%D \starttypen
+%D \defineinterfaceconstant {name} {meaning}
+%D \defineinterfacevariable {name} {meaning}
+%D \defineinterfaceelement {name} {meaning}
+%D \stoptypen
+%D
+%D Which is the same as:
+%D
+%D \starttypen
+%D \def\c!name{meaning}
+%D \def\v!name{meaning}
+%D \def\e!name{meaning}
+%D \stoptypen
+
+\def\defineinterfaceconstant #1#2{\setvalue{\c!prefix!#1}{#2}}
+\def\defineinterfacevariable #1#2{\setvalue{\v!prefix!#1}{#2}}
+\def\defineinterfaceelement #1#2{\setvalue{\e!prefix!#1}{#2}}
+
+%D Next come some interface independant constants:
+%D
+%D \starttypen
+%D \definereferenceconstant {name} {meaning}
+%D \definefileconstant {name} {meaning}
+%D \stoptypen
+
+\def\definereferenceconstant #1#2{\setvalue{\r!prefix!#1}{#2}}
+\def\definefileconstant #1#2{\setvalue{\f!prefix!#1}{#2}}
+
+%D And finaly we have the one argument, space saving constants
+%D
+%D \starttypen
+%D \definesystemconstant {name}
+%D \definemessageconstant {name}
+%D \stoptypen
+
+\def\definesystemconstant #1{\setvalue{\s!prefix!#1}{#1}}
+\def\definemessageconstant #1{\setvalue{\m!prefix!#1}{#1}}
+
+%D In a parameter driven system, some parameters are shared
+%D by more system components. In \CONTEXT\ we can distinguish
+%D parameters by a unique prefix. Such a prefix is defined
+%D with:
+%D
+%D \starttypen
+%D \definesystemvariable {name}
+%D \stoptypen
+
+\def\definesystemvariable #1{\setevalue{\??prefix#1}{\@@prefix#1}}
+
+%D \macros
+%D {selectinterface,
+%D defaultinterface, currentinterface, currentresponses}
+%D {}
+%D
+%D With \type{\selectinterface} we specify the language we are
+%D going to use. The system asks for the language wanted, and
+%D defaults to \type{\currentinterface} when we just give
+%D \type{enter}. By default the message system uses the
+%D current interface language, but \type{\currentresponses}
+%D can specify another language too.
+%D
+%D Because we want to generate formats directly too, we do
+%D not ask for interface specifications when these are already
+%D defined (like in cont-nl.tex and alike).
+
+\ifx\defaultinterface\undefined
+
+ \def\defaultinterface{dutch}
+
+ \def\selectinterface%
+ {\def\docommando##1##2%
+ {\bgroup
+ \endlinechar=-1
+ \global\read16 to ##1
+ \egroup
+ \doif{\currentinterface}{}{\let##1=##2}%
+ \doifundefined{\s!prefix!##1}{\let##1=##2}}%
+ \docommando\currentinterface\defaultinterface
+ \writestatus{interface}{defining \currentinterface\space interface}%
+ \writeline
+ \docommando\currentresponses\currentinterface
+ \writestatus{interface}{using \currentresponses\space messages}%
+ \writeline}
+
+\else
+
+ \def\selectinterface%
+ {\writestatus{interface}{defining \currentinterface\space interface}%
+ \writeline
+ \writestatus{interface}{using \currentresponses\space messages}%
+ \writeline}
+
+\fi
+
+\ifx\currentinterface\undefined \let\currentinterface=\defaultinterface \fi
+\ifx\currentresponses\undefined \let\currentresponses=\defaultinterface \fi
+
+%D \macros
+%D {startinterface}
+%D {}
+%D
+%D Sometimes we want to define things only for specific
+%D interface languages. This can be done by means of the
+%D selector:
+%D
+%D \starttypen
+%D \startinterface language
+%D
+%D language specific definitions & commands
+%D
+%D \stopinterface
+%D \stoptypen
+
+%\long\def\startinterface #1 #2\stopinterface%
+% {\doifelse{#1}{\currentinterface}
+% {\long\def\next{#2}}
+% {\let\next=\relax}%
+% \next}
+
+\def\startinterface #1
+ {\doifelse{#1}{\currentinterface}
+ {\let\next\relax}
+ {\long\def\next##1\stopinterface{}}%
+ \next}
+
+\let\stopinterface=\relax
+
+%D \macros
+%D {startmessages,
+%D getmessage,
+%D showmessage,
+%D makemessage}
+%D {}
+%D
+%D A package as large as \CONTEXT\ can hardly function without
+%D a decent message mechanism. Due to its multi||lingual
+%D interface, the message subsystem has to be multi||lingual
+%D too. A major drawback of this feature is that we have to
+%D code messages. As a result, the source becomes less self
+%D documented. On the other hand, consistency will improve.
+%D
+%D Because the overhead in terms of entries in the (already
+%D exhausted) hash table has to be minimal, messages are packed
+%D in libraries. We can extract a message from such a library
+%D in three ways:
+%D
+%D \starttypen
+%D \getmessage {library} {tag}
+%D \showmessage {library} {tag} {data}
+%D \makemessage {library} {tag} {data}
+%D \stoptypen
+%D
+%D The first command gets the message \type{tag} from the
+%D \type{library} specified. The other commands take an extra
+%D argument: a list of items to be inserted in the message
+%D text. While \type{\showmessage} shows the message at the
+%D terminal, the other commands generate the message as text.
+%D Before we explain the \type{data} argument, we give an
+%D example of a library.
+%D
+%D \starttypen
+%D \startmessages english library: alfa
+%D title: something
+%D 1: first message
+%D 2: second (--) message --
+%D \stopmessages
+%D \stoptypen
+%D
+%D The first message is a simple one and can be shown with:
+%D
+%D \starttypen
+%D \showmessage {alfa} {1} {}
+%D \stoptypen
+%D
+%D The second message on the other hand needs some extra data:
+%D
+%D \starttypen
+%D \showmessage {alfa} {2} {and last,to you}
+%D \stoptypen
+%D
+%D This message is shown as:
+%D
+%D \starttypen
+%D something : second (and last) message to you
+%D \stoptypen
+%D
+%D As we can see, the title entry is shown with the message.
+%D The data fields are comma separated and are specified in the
+%D message text by \type{--}.
+%D
+%D It is not required to define all messages in a library at
+%D once. We can add messages to a library in the following way:
+%D
+%D \starttypen
+%D \startmessages english library: alfa
+%D 10: tenth message
+%D \stopmessages
+%D \stoptypen
+%D
+%D Because such definitions can take place in different
+%D modules, the system gives a warning when a tag occurs more
+%D than once. The first occurrence takes preference over later
+%D ones, so we had better use a save offset, as shown in the
+%D example. As we can see, the title field is specified only
+%D the first time!
+%D
+%D Because we want to check for duplicate tags, the macros
+%D are a bit more complicated than neccessary. The \NEWLINE\
+%D token is used as message separator.
+
+\def\findinterfacemessage#1#2%
+ {\let#2\empty
+ \def\dofindinterfacemessage##1 #1: ##2\relax##3\end%
+ {\def#2{##2}}%
+ \edef\!!stringa{\getvalue{@@ms\currentmessagelibrary} #1: \relax}%
+ \expandafter\dofindinterfacemessage\!!stringa\end}
+
+\def\composemessagetext#1--#2--#3--#4--#5--#6\\%
+ {\def\docomposemessagetext##1,##2,##3,##4,##5,##6\\%
+ {\edef\currentmessagetext{#1##1#2##2#3##3#4##4#5##5}}%
+ \docomposemessagetext}
+
+\unexpanded\def\getmessage#1#2%
+ {\def\currentmessagelibrary{#1}%
+ \findinterfacemessage{#2}\currentmessagetext
+ \currentmessagetext}
+
+\unexpanded\def\makemessage#1#2#3%
+ {\def\currentmessagelibrary{#1}%
+ \findinterfacemessage{#2}\currentmessagetext
+ \@EA\composemessagetext\currentmessagetext----------\\#3,,,,,\\%
+ \currentmessagetext}
+
+\def\showmessage#1#2#3%
+ {\def\currentmessagelibrary{#1}%
+ \findinterfacemessage{#2}\currentmessagetext
+ \findinterfacemessage{title}\currentmessagetitle
+ \doifelse{\currentmessagetext}{}
+ {\def\currentmessagetext{<unknown message #2>}}
+ {\@EA\composemessagetext\currentmessagetext----------\\#3,,,,,\\}%
+ \@EA\writestatus\@EA{\currentmessagetitle}{\currentmessagetext}}
+
+\def\doaddinterfacemessage#1#2%
+ {\findinterfacemessage{#1}\currentmessagetext
+ \doifelse{\currentmessagetext}{}
+ {\setxvalue{@@ms\currentmessagelibrary}%
+ {\getvalue{@@ms\currentmessagelibrary} #1: #2\relax}}
+ {\debuggerinfotrue % we consider this an important error
+ \debuggerinfo
+ {message}
+ {duplicate tag #1
+ in library \currentmessagelibrary\space
+ of interface \currentresponses}}%
+ \futurelet\next\getinterfacemessage}
+
+\bgroup
+\obeylines
+\gdef\addinterfacemessage#1: #2
+ {\doaddinterfacemessage{#1}{#2}}%
+\egroup
+
+\def\getinterfacemessage%
+ {\ifx\next\stopmessages
+ \def\next##1{\egroup}%
+ \else
+ \let\next\addinterfacemessage
+ \fi
+ \next}
+
+\gdef\startmessages #1 library: #2
+ {\bgroup
+ \obeylines
+ \doifinsetelse{#1}{\currentresponses,all}
+ {\def\next%
+ {\def\currentmessagelibrary{#2}%
+ \doifundefined{@@ms\currentmessagelibrary}
+ {\setgvalue{@@ms\currentmessagelibrary}{}}%
+ \futurelet\next\getinterfacemessage}}
+ {\long\def\next##1\stopmessages{\egroup}}%
+ \next}
+
+%D \macros
+%D {ifshowwarnings, ifshowmessages}
+%D
+%D Sometimes displaying message can slow down processing
+%D considerably. We therefore introduce warnings. Users can
+%D turn of warnings and messages by saying:
+%D
+%D \starttypen
+%D \showwarningstrue
+%D \showmessagestrue
+%D \stoptypen
+%D
+%D Turning off messages also turns off warnings, which is
+%D quote logical because they are less important.
+
+\newif\ifshowwarnings \showwarningstrue
+\newif\ifshowmessages \showmessagestrue
+
+\let\normalshowmessage=\showmessage
+
+\def\showwarning%
+ {\ifshowwarnings
+ \expandafter\showmessage
+ \else
+ \expandafter\gobblethreearguments
+ \fi}
+
+\def\showmessage%
+ {\ifshowmessages
+ \expandafter\normalshowmessage
+ \else
+ \expandafter\gobblethreearguments
+ \fi}
+
+%D \macros
+%D {dosetvalue,dosetevalue,docopyvalue,doresetvalue,
+%D dogetvalue}
+%D {}
+%D
+%D We already defined these auxiliary macros in the system
+%D modules. Starting with this module however, we have to take
+%D multi||linguality a bit more serious.
+%D
+%D First we show a well||defined alternative:
+%D
+%D \starttypen
+%D \def\dosetvalue#1#2#3%
+%D {\doifdefinedelse{\c!prefix!#2}
+%D {\setvalue{#1\getvalue{\c!prefix!#2}}{#3}}
+%D {\setvalue{#1#2}{#3}}}
+%D
+%D \def\docopyvalue#1#2#3%
+%D {\doifdefinedelse{\c!prefix!#3}
+%D {\setvalue{#1\getvalue{\c!prefix!#3}}%
+%D {\getvalue{#2\getvalue{\c!prefix!#3}}}}
+%D {\setvalue{#1#3}%
+%D {\getvalue{#2#3}}}}
+%D
+%D \def\dogetvalue#1#2%
+%D {\getvalue{#1\getvalue{\c!prefix!#2}}}
+%D \stoptypen
+%D
+%D These macros are called upon quite often and so we optimized
+%D them a bit.
+
+\def\dosetvalue#1#2#3%
+ {\p!doifundefined{\c!prefix!#2}%
+ \let\donottest\doprocesstest
+ \@EA\def\csname#1#2\endcsname{#3}%
+ \else
+ \let\donottest\doprocesstest
+ \@EA\def\csname#1\csname\c!prefix!#2\endcsname\endcsname{#3}%
+ \fi}
+
+\def\dosetevalue#1#2#3%
+ {\p!doifundefined{\c!prefix!#2}%
+ \let\donottest\doprocesstest
+ \@EA\edef\csname#1#2\endcsname{#3}%
+ \else
+ \let\donottest\doprocesstest
+ \@EA\edef\csname#1\csname\c!prefix!#2\endcsname\endcsname{#3}%
+ \fi}
+
+\def\docopyvalue#1#2#3%
+ {\p!doifundefined{\c!prefix!#3}%
+ \let\donottest\doprocesstest
+ \@EA\def\csname#1#3\endcsname%
+ {\csname#2#3\endcsname}%
+ \else
+ \let\donottest\doprocesstest
+ \@EA\def\csname#1\csname\c!prefix!#3\endcsname\endcsname%
+ {\csname#2\csname\c!prefix!#3\endcsname\endcsname}%
+ \fi}
+
+\def\doresetvalue#1#2%
+ {\dosetvalue{#1}{#2}{}}
+
+\def\dogetvalue#1#2%
+ {\csname#1\csname\c!prefix!#2\endcsname\endcsname}
+
+%D Although maybe bot clearly visible, there is a
+%D considerable profit in further optimalization. By expanding
+%D the embedded \type{\csname} we can reduce the format file
+%D by about 5\% (60~KB out of 1.9~MB).
+
+\def\docopyvalue#1#2#3%
+ {\p!doifundefined{\c!prefix!#3}%
+ \let\donottest\doprocesstest
+ \@EA\@EA\@EA\def\@EA\csname\@EA#1\@EA#3\@EA\endcsname
+ \@EA{\csname#2#3\endcsname}%
+ \else
+ \let\donottest\doprocesstest
+ \@EA\@EA\@EA\def\@EA
+ \csname
+ \@EA#1\@EA\csname\@EA\c!prefix!\@EA#3\@EA\endcsname\@EA
+ \endcsname
+ \@EA{\csname#2\csname\c!prefix!#3\endcsname\endcsname}%
+ \fi}
+
+%D We take this opportunity of redefining to adapt an
+%D assignment macro. The change has to do with the fact that the
+%D generated error message must be multi||lingual. We can not
+%D define the message yet, because we still have to select the
+%D interface language.
+
+%\def\p!doassign#1[#2][#3=#4=#5]%
+% {\let\donottest=\dontprocesstest
+% \edef\!!stringa{#5}%
+% \edef\!!stringb{\relax}%
+% \let\donottest=\doprocesstest
+% \ifx\!!stringa\!!stringb
+% \showmessage{check}{1}{#3,\the\inputlineno}%
+% \else
+% #1{#2}{#3}{#4}%
+% \fi}
+
+\def\p!doassign#1[#2][#3=#4=#5]%
+ {\ifx\empty#3\else % and definitely not \ifx#3\empty
+ \ifx\relax#5%
+ \showmessage{check}{1}{#3,\the\inputlineno}%
+ \else
+ #1{#2}{#3}{#4}%
+ \fi
+ \fi}
+
+\def\dogetargument#1#2#3#4%
+ {\doifnextcharelse{#1}
+ {\let\expectedarguments\noexpectedarguments
+ #3\dodogetargument}
+ {\ifnum\expectedarguments>\noexpectedarguments
+ \showmessage{check}{2}{\the\expectedarguments,\the\inputlineno}%
+ \fi
+ \let\expectedarguments\noexpectedarguments
+ #4\dodogetargument#1#2}}
+
+\def\dogetgroupargument#1#2%
+ {\def\nextnextargument%
+ {\ifx\nextargument\bgroup
+ \let\expectedarguments\noexpectedarguments
+ \def\nextargument{#1\dodogetargument}%
+ %\else\ifx\nextargument\lineending % this can be an option
+ % \def\nextargument{\bgroup\def\\ {\egroup\dogetgroupargument#1#2}\\}%
+ %\else\ifx\nextargument\blankspace % but may never be default
+ % \def\nextargument{\bgroup\def\\ {\egroup\dogetgroupargument#1#2}\\}%
+ \else
+ \ifnum\expectedarguments>\noexpectedarguments
+ \showmessage{check}{2}{\the\expectedarguments,\the\inputlineno}%
+ \fi
+ \let\expectedarguments\noexpectedarguments
+ \def\nextargument{#2\dodogetargument{}}%
+ \fi%\fi\fi % so let's get rid of it
+ \nextargument}%
+ \futurelet\nextargument\nextnextargument}
+
+\def\checkdefined#1#2#3%
+ {\doifdefined{#3}
+ {\showmessage{check}{3}{#2,#3}}}
+
+%D \CONTEXT\ is a parameter driven package. This means that
+%D users instruct the system by means of variables, values and
+%D keywords. These instructions take the form:
+%D
+%D \starttypen
+%D \setupsomething[some variable=some value, another one=a keyword]
+%D \stoptypen
+%D
+%D or by keyword only:
+%D
+%D \starttypen
+%D \dosomething[this way, that way, no way]
+%D \stoptypen
+%D
+%D Because the same variables can occur in more than one setup
+%D command, we have to be able to distinguish them. This is
+%D achieved by assigning them a unique prefix.
+%D
+%D Imagine a setup command for boxed text, that enables us to
+%D specify the height and width of the box. Behide the scenes
+%D the command
+%D
+%D \starttypen
+%D \setupbox [width=12cm, height=3cm]
+%D \stoptypen
+%D
+%D results in something like
+%D
+%D \starttypen
+%D \<box><width> {12cm}
+%D \<box><height> {3cm}
+%D \stoptypen
+%D
+%D while a similar command for specifying the page dimensions
+%D of an \kap{A4} page results in:
+%D
+%D \starttypen
+%D \<page><width> {21.0cm}
+%D \<page><height> {27.9cm}
+%D \stoptypen
+%D
+%D The prefixes \type{<box>} and \type{<page>} are hidden from
+%D users and can therefore be language independant. Variables
+%D on the other hand, differ for each language:
+%D
+%D \starttypen
+%D \<box><color> {<blue>}
+%D \<box><kleur> {<blauw>}
+%D \<box><couleur> {<blue>}
+%D \stoptypen
+%D
+%D In this example we can see that the assigned values or
+%D keywords are language dependant too. This will be a
+%D complication when defining multi||lingual setup files.
+%D
+%D A third phenomena is that variables and values can have a
+%D similar meaning.
+%D
+%D \starttypen
+%D \<pagenumber><location> {<left>}
+%D \<skip><left> {12cm}
+%D \stoptypen
+%D
+%D A (minor) complication is that where in english we use
+%D \type{<left>}, in dutch we find both \type{<links>} and
+%D \type{<linker>}. This means that when we use some sort of
+%D translation table, we have to distinguish between the
+%D variables at the left side and the fixed values at the
+%D right.
+%D
+%D The same goes for commands that are composed of different
+%D user supplied and/or language specific elements. In english
+%D we can use:
+%D
+%D \starttypen
+%D \<empty><figure>
+%D \<empty><intermezzo>
+%D \stoptypen
+%D
+%D But in dutch we have the following:
+%D
+%D \starttypen
+%D \<lege><figuur>
+%D \<leeg><intermezzo>
+%D \stoptypen
+%D
+%D These subtle differences automatically lead to a solution
+%D where variables, values, elements and other components have
+%D a similar logical name (used in macro's) but a different
+%D meaning (supplied by the user).
+%D
+%D Our solution is one in which the whole system is programmed
+%D in terms of identifiers with language specific meanings. In
+%D such an implementation, each fixed variable is available as:
+%D
+%D \starttypen
+%D \<prefix><variable>
+%D \stoptypen
+%D
+%D This means that for instance:
+%D
+%D \starttypen
+%D \setupbox[width=12cm]
+%D \stoptypen
+%D
+%D expands to something like:
+%D
+%D \starttypen
+%D \def\boxwidth{12cm}
+%D \stoptypen
+%D
+%D because we don't want to recode the source, a setup command
+%D in another language has to expand to this variable, so:
+%D
+%D \starttypen
+%D \stelblokin[breedte=12cm]
+%D \stoptypen
+%D
+%D has to result in the definition of \type{\boxwidth} too.
+%D This method enables us to build compact, fast and readable
+%D code.
+%D
+%D An alternative method, which we considered using, uses a
+%D more indirect way. In this case, both calls generate a
+%D different variable:
+%D
+%D \starttypen
+%D \def\boxwidth {12cm}
+%D \def\boxbreedte {12cm}
+%D \stoptypen
+%D
+%D And because we don't want to recode those megabytes of
+%D already developed code, this variable has to be called with
+%D something like:
+%D
+%D \starttypen
+%D \valueof\box\width
+%D \stoptypen
+%D
+%D where \type{\valueof} takes care of the translation of
+%D \type{width} or \type{breedte} to \type{width} and
+%D combining this with \type{box} to \type{\boxwidth}.
+%D
+%D One advantage of this other scheme is that, within certain
+%D limits, we can implement an interface that can be switched
+%D to another language at will, while the current approach
+%D fixes the interface at startup. There are, by the way,
+%D other reasons too for not choosing this scheme. Switching
+%D user generated commands is for instance impossible and a
+%D dual interface would therefore give a strange mix of
+%D languages.
+%D
+%D Now let's work out the first scheme. Although the left hand
+%D of the assignment is a variable from the users point of
+%D view, it is a constant in terms of the system. Both
+%D \type{width} and \type{breedte} expand to \type{width}
+%D because in the source we only encounter \type{width}. Such
+%D system constants are presented as
+%D
+%D \starttypen
+%D \c!width
+%D \stoptypen
+%D
+%D This constant is always equivalent to \type{width}. As we
+%D can see, we use \type{c!} to mark this one as constant. Its
+%D dutch counterpart is:
+%D
+%D \starttypen
+%D \c!breedte
+%D \stoptypen
+%D
+%D When we interpret a setup command each variable is
+%D translated to it's \type{c!} counterpart. This means that
+%D \type{breedte} and \type{width} expand to \type{\c!breedte}
+%D and \type{\c!width} which both expand to \type{width}. That
+%D way user variables become system constants.
+%D
+%D The interpretation is done by means of a general setup
+%D command \type{\getparameters} that we introduced in the
+%D system module. Let us define some simple setup command:
+%D
+%D \starttypen
+%D \def\setupbox[#1]%
+%D {\getparameters[\??bx][#1]}
+%D \stoptypen
+%D
+%D This command can be used as:
+%D
+%D \starttypen
+%D \setupbox [width=3cm, height=1cm]
+%D \stoptypen
+%D
+%D Afterwards we have two variables \type{\@@bxwidth} and
+%D \type{\@@bxheight} which have the values \type{3cm} and
+%D \type{1cm} assigned. These variables are a combinatiom of
+%D the setup prefix \type{\??bx}, which expands to \type{@@bx}
+%D and the translated user supplied variables \type{width} and
+%D \type{height} or \type{breedte} and \type{hoogte},
+%D depending on the actual language. In dutch we just say:
+%D
+%D \starttypen
+%D \stelblokin [breedte=3cm, hoogte=1cm]
+%D \stoptypen
+%D
+%D and get ourselves \type{\@@bxwidth} and \type{\@@bxheight}
+%D too. In the source of \CONTEXT, we can recognize constants
+%D and variables on their leading \type{c!}, \type{v!} etc.,
+%D prefixes on \type{??} and composed variables on \type{@@}.
+%D
+%D We already saw that user supplied keywords need some
+%D special treatment too. This time we don't translate the
+%D keyword, but instead use in the source a variable which
+%D meaning depends on the interface language.
+%D
+%D \starttypen
+%D \v!left
+%D \stoptypen
+%D
+%D Which can be used in macro's like:
+%D
+%D \starttypen
+%D \processaction
+%D [\@@bxlocation]
+%D [ \v!left=>\dosomethingontheleft,
+%D \v!middle=>\dosomthinginthemiddle,
+%D \v!right=>\dosomethingontheright]
+%D \stoptypen
+%D
+%D Because variables like \type{\@@bxlocation} can have a lot
+%D of meanings, including tricky expandable tokens, we cannot
+%D translate this meaning when we compare. This means that
+%D \type{\@@bxlocation} can be \type{left} of \type{links} of
+%D whatever meaning suits the language. But because
+%D \type{\v!left} also has a meaning that suits the language,
+%D we are able to compare.
+%D
+%D Although we know it sounds confusing we want to state two
+%D important characteristics of the interface as described:
+%D
+%D \startsmaller \em
+%D user variables become system constants
+%D \stopsmaller
+%D
+%D and
+%D
+%D \startsmaller \em
+%D user constants (keywords) become system variables
+%D \stopsmaller
+%D
+
+%D \macros
+%D {startconstants,startvariables}
+%D {}
+%D
+%D It's time to introduce the macro's that are responsible for
+%D this translations process, but first we show how constants
+%D and variables are defined. We only show two languages and
+%D a few words.
+%D
+%D \starttypen
+%D \startconstants english dutch
+%D
+%D width: width breedte
+%D height: height hoogte
+%D
+%D \stopconstants
+%D \stoptypen
+%D
+%D Keep in mind that what users see as variables, are constants
+%D for the system.
+%D
+%D \starttypen
+%D \startvariables english dutch
+%D
+%D location: left links
+%D text: text tekst
+%D
+%D \stopvariables
+%D \stoptypen
+%D
+%D The macro's responsible for interpreting these setups are
+%D shared. They take care of empty lines and permit a more or
+%D less free format. All setups accept the keyword \type{all}
+%D which equals every language.
+
+\def\nointerfaceobject{-}
+
+\def\startinterfaceobjects#1#2%
+ {\!!counta=1
+ \let\dogetinterfaceobject\dogetinterfacetemplate
+ \let\dowithinterfaceelement#1%
+ \def\dodogetinterfaceobjects%
+ {\ifx\next#2%
+ \def\next####1%
+ {}%
+ \else\ifx\next\par
+ \long\def\next####1%
+ {\dogetinterfaceobjects}%
+ \else\ifx\next\empty
+ \def\next####1%
+ {\dogetinterfaceobjects}%
+ \else
+ \def\next####1 %
+ {\dogetinterfaceobject[####1:\relax]%
+ \dogetinterfaceobjects}%
+ \fi\fi\fi
+ \next}%
+ \def\dogetinterfaceobjects%
+ {\futurelet\next\dodogetinterfaceobjects}%
+ \dogetinterfaceobjects}
+
+\def\dogetinterfacetemplate[#1:#2]%
+ {\doifinsetelse{#1}{\currentinterface,all}
+ {\let\dogetinterfaceobject\doskipinterfaceobject}
+ {\advance\!!counta by 1\relax}}
+
+\def\doskipinterfaceobject[#1:#2#3]%
+ {\if#2:%
+ \let\dogetinterfaceobject\dogetinterfaceelement
+ \dogetinterfaceobject[#1:#2#3]%
+ \fi}
+
+\def\dogetinterfaceelement[#1:#2#3]%
+ {\ifx#2:%
+ \!!countb=0
+ \def\!!stringa{#1}%
+ \else
+ \advance\!!countb by 1
+ \ifnum\!!countb=\!!counta
+ \@EA\dowithinterfaceelement\@EA{\!!stringa}{#1}%
+ \let\dogetinterfaceobject\doskipinterfaceobject
+ \fi
+ \fi}
+
+%D The constants and variables are defined as described. When
+%D \type{\interfacetranslation} is \type{true}, we also
+%D generate a reverse translation. Because we don't want to put
+%D too big a burden on \TEX's hash table, this is no default
+%D behavior. Reverse translation is used in the commands that
+%D generate the quick reference cards. We are going to define
+%D the real \CONTEXT\ commands in an abstract way and generate
+%D those reference cards for each language without further
+%D interference.
+
+\def\setinterfaceconstant#1#2%
+ {\setvalue{\c!prefix!#1}{#1}%
+ \doifelse{#2}{\nointerfaceobject}
+ {\debuggerinfo{constant}{#1 defined as #1 by default}}
+ {\debuggerinfo{constant}{#1 defined as #2}%
+ \ifinterfacetranslation
+ \setvalue{\x!prefix!#1}{#2}%
+ \fi
+ \setvalue{\c!prefix!#2}{#1}}}
+
+\def\setinterfacevariable#1#2%
+ {\doifelse{#2}{\nointerfaceobject}
+ {\debuggerinfo{variable}{#1 defined as #1 by default}%
+ \setvalue{\v!prefix!#1}{#1}}
+ {\debuggerinfo{variable}{#1 defined as #2}%
+ \setvalue{\v!prefix!#1}{#2}}}
+
+\def\startvariables%
+ {\startinterfaceobjects\setinterfacevariable\stopvariables}
+
+\def\startconstants%
+ {\startinterfaceobjects\setinterfaceconstant\stopconstants}
+
+%D \macros
+%D {defineinterfaceconstant}
+%D
+%D Next we redefine a previously defined macro to take care of
+%D interface translation too. It's a bit redundant, because
+%D in thise situations we could use the c||version, but for
+%D documentation purposes the x||alternative comes in handy.
+
+\def\defineinterfaceconstant#1#2%
+ {\setvalue{\c!prefix!#1}{#2}%
+ \ifinterfacetranslation
+ \setvalue{\x!prefix!#1}{#2}%
+ \fi}
+
+%D \macros
+%D {startinterfacesetupconstant}
+%D {}
+%D
+%D The next command, \type{\startinterfacesetupconstant}, which
+%D behavior also depends on the boolean, is used for constants
+%D that are only needed in these quick reference macro's. The
+%D following, more efficient approach does not work here,
+%D because it sometimes generates spaces.
+%D
+%D \starttypen
+%D \def\setinterfacesetupconstant%
+%D {\ifinterfacetranslation
+%D \expandafter\setinterfaceconstant
+%D \fi}
+%D \stoptypen
+%D
+%D We therefore use the more redundant but robust method:
+
+\def\setinterfacesetupvariable#1#2%
+ {\ifinterfacetranslation
+ \doifelse{#2}{\nointerfaceobject}
+ {\setvalue{\y!prefix!#1}{#1}}
+ {\setvalue{\y!prefix!#1}{#2}}%
+ \fi}
+
+\def\startsetupvariables%
+ {\startinterfaceobjects\setinterfacesetupvariable\stopsetupvariables}
+
+%D \macros
+%D {startelements}
+%D {}
+%D
+%D Due to the object oriented nature of \CONTEXT, we also need
+%D to define the elements that are used to build commands:
+%D
+%D \starttypen
+%D \startelements english dutch
+%D
+%D beginvan: begin beginvan
+%D eindvan: end eindvan
+%D start: start start
+%D stop: stop stop
+%D
+%D \stopelements
+%D \stoptypen
+%D
+%D Such elements sometimes are the same in diferent
+%D languages, but mostly they differ. Things can get even
+%D confusing when we look at for instance the setup commands.
+%D In english we say \type{\setup<something>}, but in dutch we
+%D have: \type{\stel<iets>in}. Such split elements are no
+%D problem, because we just define two elements. When no second
+%D part is needed, we use a \type{-}:
+%D
+%D \starttypen
+%D \startelements english dutch
+%D
+%D setupa: setup stel
+%D setupb: - in
+%D
+%D \stopelements
+%D \stoptypen
+%D
+%D Element translation is realized by means of:
+
+\def\setinterfaceelement#1#2%
+ {\doifelse{#2}{\nointerfaceobject}
+ {\debuggerinfo{element}{#1 defined as <empty>}%
+ \resetvalue{\e!prefix!#1}}
+ {\doifdefinedelse{\e!prefix!#1}
+ {\doifnot{\getvalue{\e!prefix!#1}}{#2}
+ {\debuggerinfo{element}{#1 redefined as #2}%
+ \setvalue{\e!prefix!#1}{#2}}}
+ {\debuggerinfo{element}{#1 defined as #2}%
+ \setvalue{\e!prefix!#1}{#2}}}}
+
+\def\startelements%
+ {\startinterfaceobjects\setinterfaceelement\stopelements}
+
+%D \macros
+%D {startcommands}
+%D {}
+%D
+%D The last setup has to do with the commands themselve.
+%D Commands are defined as:
+%D
+%D \starttypen
+%D \startcommands english dutch
+%D
+%D starttekst: starttext starttekst
+%D stoptekst: stoptext stoptekst
+%D omlijnd: framed omlijnd
+%D margewoord: marginword margewoord
+%D
+%D \stopcommands
+%D \stoptypen
+%D
+%D Here we also have to take care of the optional translation
+%D needed for reference cards.
+
+\def\setinterfacecommand#1#2%
+ {\doifelse{#2}{\nointerfaceobject}
+ {\debuggerinfo{command}{no link to #1}%
+ \setinterfacesetupvariable{#1}{#1}}
+ {\doifelse{#1}{#2}
+ {\debuggerinfo{command}{#1 remains #1}}
+ {\doifdefinedelse{#2}
+ {\debuggerinfo{command}{core command #2 redefined as #1}}%
+ {\debuggerinfo{command}{#2 defined as #1}}%
+ \@EA\@EA\@EA\def\@EA\csname\@EA#2\@EA\endcsname
+ \@EA{\csname#1\endcsname}}%
+ \setinterfacesetupvariable{#1}{#2}}}
+
+\def\startcommands%
+ {\startinterfaceobjects\setinterfacecommand\stopcommands}
+
+%D \macros
+%D {getinterfaceconstant, getinterfacevariable}
+%D {}
+%D
+%D Generating the interface translation macro's that are used
+%D in the reference lists, is enabled by setting the boolean:
+%D
+%D \starttypen
+%D \interfacetranslationtrue
+%D \stoptypen
+%D
+%D Keep in mind that enabling interfacetranslation costs a
+%D bit of hash space.
+
+\newif\ifinterfacetranslation
+
+\def\getinterfaceconstant#1%
+ {\ifinterfacetranslation
+ \doifdefinedelse{\x!prefix!#1}
+ {\getvalue{\x!prefix!#1}}
+ {#1}%
+ \else
+ #1%
+ \fi}
+
+\def\getinterfacevariable#1%
+ {\ifinterfacetranslation
+ \doifdefinedelse{\y!prefix!#1}
+ {\getvalue{\y!prefix!#1}}
+ {#1}%
+ \else
+ #1%
+ \fi}
+
+%D When a reference list is generated, one does not need to
+%D generate a new format. Just reloading the relevant
+%D definition files suits:
+%D
+%D \starttypen
+%D \interfacetranslationtrue
+%D \input mult-con
+%D \input mult-com
+%D \stoptypen
+
+%D \macros
+%D {interfaced}
+%D {}
+%D
+%D The setup commands translate the constants automatically.
+%D When we want to translate 'by hand' we can use the simple
+%D but effective command:
+%D
+%D \starttypen
+%D \interfaced {something}
+%D \stoptypen
+%D
+%D Giving \type{\interfaced{breedte}} results in \type{width}
+%D or, when not defined, in \type{breedte} itself.
+
+\def\interfaced#1%
+ {\expandafter\ifx\csname\c!prefix!#1\endcsname\relax
+ #1%
+ \else
+ \csname\c!prefix!#1\endcsname
+ \fi}
+
+%D So much for the basic multi||lingual interface commands. The
+%D macro's can be enhanced with more testing facilities, but
+%D for the moment they suffice.
+
+\protect
+
+\endinput
+ \ No newline at end of file
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-05 00:48:48 +0000