%D \module
%D   [       file=typo-dig,
%D        version=2010.01.18,
%D          title=\CONTEXT\ Typesetting Macros,
%D       subtitle=Digits,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Typesetting Macros / Local Boxes}

% musical timestamp: New Scary Goldings ft. John Scofield MonoNeon & Louis Cole (late
% October 2021)

% maybe: \iflocalleftbox

\registerctxluafile{typo-lbx}{autosuffix}

%D The advantage is that it's deal with in the par builder which has some advantages
%D but when used in complex situation there can be side effects. Therefore is should
%D be considered a somewhat low level mechanism on top of which one can write more
%D mechanisms that provide more rendering control. Also, keep in mind that combining
%D many instances at the same time add some complizity. Therefore, for the moment it's
%D a playground.


\unprotect

\def\v!lefttext {lefttext}
\def\v!righttext{righttext}

\appendtoks
    \localleftbox {}% \nolocalboxes : we don't have a nice command category for it
    \localrightbox{}%
\to\everyforgetall

\definesystemattribute[localboxes][public]

%D We used to pass arguments but there might be many so ...

\newbox\localboxcontentbox

\installcorenamespace{localboxes}
\installcorenamespace{localboxesattribute}
\installcorenamespace{localboxesnamespace}
\installcorenamespace{localboxeslocations}

\installcommandhandler \??localboxes {localboxes} \??localboxes

\setuplocalboxes
  [\c!location=\v!left]

\newcount\c_typo_localboxes

\appendtoks
    \global\advance\c_typo_localboxes\plusone
    \global\expandafter\integerdef\csname\??localboxesattribute\currentlocalboxes\endcsname\c_typo_localboxes
    \gletcsname\??localboxesnamespace\number\c_typo_localboxes\endcsname\currentlocalboxes
\to \everydefinelocalboxes

%D The optional argument forces seting the \quote {whole} paragraph properties (which is needed
%D when the assignment happens after e.g.\ \type {\everypar} but is also meant for the first
%D line.

\def\typo_paragraphs_l#1{\localleftbox \ifcstok{#1}\v!global par\fi}
\def\typo_paragraphs_r#1{\localrightbox\ifcstok{#1}\v!global par\fi}

\permanent\tolerant\protected\def\leftparbox        [#1]{\typo_paragraphs_l{#1}\bgroup\enforced\let\leftparbox \relax\let\next}
\permanent\tolerant\protected\def\rightparbox       [#1]{\typo_paragraphs_r{#1}\bgroup\enforced\let\rightparbox\relax\let\next}

\permanent\tolerant\protected\def\appendleftparbox  [#1]{\dowithnextbox{\leftparbox [#1]{\the\localleftbox \unhbox\nextbox}}\hbox}
\permanent\tolerant\protected\def\appendrightparbox [#1]{\dowithnextbox{\rightparbox[#1]{\the\localrightbox\unhbox\nextbox}}\hbox}

\permanent\tolerant\protected\def\prependleftparbox [#1]{\dowithnextbox{\leftparbox [#1]{\unhbox\nextbox\the\localleftbox }}\hbox}
\permanent\tolerant\protected\def\prependrightparbox[#1]{\dowithnextbox{\rightparbox[#1]{\unhbox\nextbox\the\localrightbox}}\hbox}

\permanent\tolerant\protected\def\resetleftparbox   [#1]{\typo_paragraphs_l{#1}{}}
\permanent\tolerant\protected\def\resetrightparbox  [#1]{\typo_paragraphs_r{#1}{}}

% called back:

\permanent\protected\def\localboxcommand
  {\ifcsname\??localboxesnamespace\number\localboxattribute\endcsname
    %\edef\currentlocalboxes{\lastnamedcs}%
     \expandafter\let\expandafter\currentlocalboxes\lastnamedcs
     \setbox\localboxcontentbox\hbox
       {\uselocalboxesstyleandcolor\c!style\c!color
        \localboxesparameter\c!command}%
   \fi}

%D We don't group because we set the local boxes. Also, watch out: by injecting the
%D existing local box we create nested ones. This is handled in the callback but if
%D really needed one can do something like (do we need a primitive?):

% \localrightbox{%
%   \the\localrightbox
%   \setbox\scratchbox\lastbox
%   \unhbox\scratchbox
%   additional}%

\def\typo_localboxes_zero#1#2%
  {\ifcsname\??localboxesattribute#1\endcsname
     \hpack attr \localboxesattribute \lastnamedcs to \zeropoint \bgroup
        \edef\currentlocalboxes{#1}%
        #2%
     \egroup
   \fi}

\def\typo_localboxes_asis#1#2%
  {\hpack \bgroup  % todo: use width if dimension, use distance if given
     \edef\currentlocalboxes{#1}%
     \localboxesparameter\c!command{#2}%
   \egroup}

\defcsname\??localboxeslocations\v!left\endcsname#1#2%
  {\leftparbox \bgroup
     \typo_localboxes_zero{#1}{#2}%
     \the\localleftbox
   \egroup}

\defcsname\??localboxeslocations\v!right\endcsname#1#2%
  {\rightparbox \bgroup
     \the\localrightbox
     \typo_localboxes_zero{#1}{#2}%
   \egroup}

\defcsname\??localboxeslocations\v!lefttext\endcsname#1#2%
  {\leftparbox \bgroup
     \typo_localboxes_asis{#1}{#2}%
     \the\localleftbox
   \egroup}

\defcsname\??localboxeslocations\v!righttext\endcsname#1#2%
  {\rightparbox \bgroup
     \the\localrightbox
     \typo_localboxes_asis{#1}{#2}%
   \egroup}

\permanent\tolerant\protected\def\localbox[#1]%
  {\dowithnextboxcontent
     {\edef\currentlocalboxes{#1}%
      \uselocalboxesstyleandcolor\c!style\c!color}
     {\ifcsname\??localboxeslocations\namedlocalboxesparameter{#1}\c!location\endcsname
        \expandafter\lastnamedcs
      \else
        \csname\??localboxeslocations\v!left\expandafter\endcsname
      \fi{#1}{\unhbox\nextbox}}%
     \hbox}

\permanent\tolerant\protected\def\startlocalbox[#1]%
  {\dowithnextbox
     {\ifcsname\??localboxeslocations\namedlocalboxesparameter{#1}\c!location\endcsname
         \expandafter\lastnamedcs
       \else
         \csname\??localboxeslocations\v!left\expandafter\endcsname
       \fi{#1}{\unhbox\nextbox}}%
     \hbox\bgroup
     \edef\currentlocalboxes{#1}%
     \uselocalboxesstyleandcolor\c!style\c!color
     \enforced\def\stoplocalbox{\removeunwantedspaces\egroup}%
     \ignorespaces}

\aliased\let\stoplocalbox\donothing

%D Here is an example of usage:

%D \starttyping
%D \definelocalboxes
%D   [linenumber]
%D   [command=\LeftNumber,location=left,width=3em,style=\bs,color=darkred]
%D
%D \definelocalboxes
%D   [linenumbertwo] [linenumber]
%D   [command=\RightNumber,location=right,width=6em,style=\bf,color=darkgreen]
%D
%D \definelocalboxes
%D   [linetext]
%D   [command=\LeftText,location=lefttext,style=\bs,color=darkblue]
%D
%D \definelocalboxes
%D   [linetexttwo] [linetext]
%D   [command=\RightText,location=righttext,style=\bf,color=darkgray]
%D
%D % \def\LineNumberL{\the\localboxlinenumber}
%D % \def\LineNumberR{\the\localboxlinenumber}
%D
%D % \newcount\MyLineNumberL
%D % \newcount\MyLineNumberR
%D % \def\LineNumberL{\global\advance\MyLineNumberL\plusone\the\MyLineNumberL}
%D % \def\LineNumberR{\global\advance\MyLineNumberR\plusone\the\MyLineNumberR}
%D
%D \definecounter[MyLineNumberL]
%D \definecounter[MyLineNumberR]
%D
%D \setupcounter[MyLineNumberL][numberconversion=characters]
%D \setupcounter[MyLineNumberR][numberconversion=romannumerals]
%D
%D \def\LineNumberL{\incrementcounter[MyLineNumberL]\convertedcounter[MyLineNumberL]}
%D \def\LineNumberR{\incrementcounter[MyLineNumberR]\convertedcounter[MyLineNumberR]}
%D
%D \protected\def\LeftNumber {\hbox to \localboxesparameter{width}{\strut(\LineNumberL\hss)}}
%D \protected\def\RightNumber{\hbox to \localboxesparameter{width}{\strut(\hss\LineNumberR)}}
%D
%D % \protected\def\LeftNumber {\hbox to \localboxesparameter{width}{\strut\box\localboxcontentbox\hss)}}
%D % \protected\def\RightNumber{\hbox to \localboxesparameter{width}{\strut(\hss\box\localboxcontentbox)}}
%D
%D \protected\def\LeftText #1{#1\quad}
%D \protected\def\RightText#1{\quad#1}
%D
%D \start
%D     \localbox[linenumber]{}%
%D     \localbox[linenumbertwo]{}%
%D     \localbox[linetext]{L}%
%D     \startlocalbox[linetexttwo]
%D         R
%D     \stoplocalbox
%D     \dorecurse{100}{
%D         \samplefile{tufte}
%D         \par
%D     }
%D \stop
%D \stoptyping

\protect \endinput