%D \module
%D   [       file=anch-pgr, % moved from anch-pgr (1999.08.01)
%D        version=2011.12.19, % 1999.08.01,
%D          title=\CONTEXT\ Anchoring Macros,
%D       subtitle=Table Extensions,
%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 Anchoring Macros / Table Extensions}

%D This is just a playground and functionality might change or even
%D dissappear in favour of better solutions.

\unprotect

\newcount\c_anch_tabs

\unexpanded\def\tabl_tabulate_hook_b
  {\iftrialtypesetting\else
     \ifpositioning
\ifconditional\tablehaspositions
       \ifcase\c_tabl_tabulate_noflines % \ifnum\c_tabl_tabulate_noflines=\c_tabl_tabulate_totalnoflines
         \tabl_tabulate_hook_b_first
       \else
         \tabl_tabulate_hook_b_next
       \fi
\fi
     \fi
   \fi}

\unexpanded\def\tabl_tabulate_hook_e
  {\iftrialtypesetting\else
     \ifpositioning
\ifconditional\tablehaspositions
       \ifcase\c_tabl_tabulate_noflines % \ifnum\c_tabl_tabulate_noflines=\c_tabl_tabulate_totalnoflines
         \tabl_tabulate_hook_e_first
       \else
         \tabl_tabulate_hook_e_next
       \fi
\fi
     \fi
   \fi}

\unexpanded\def\tabl_tabulate_hook_b_first
  {\clf_bposcolumnregistered{tabulate:\the\c_anch_tabs:\the\c_tabl_tabulate_column}}

\unexpanded\def\tabl_tabulate_hook_b_next
  {\clf_bposcolumn{tabulate:\the\c_anch_tabs:\the\c_tabl_tabulate_column}}

\unexpanded\def\tabl_tabulate_hook_e_first
  {\clf_eposcolumnregistered}

\unexpanded\def\tabl_tabulate_hook_e_next
  {\clf_eposcolumn}

% \appendtoks \registerparoptions \to \everypar

\appendtoks
    \global\advance\c_anch_tabs\plusone
\to \everytabulate

% for text backgrounds

\appendtoks
    \settrue\c_anch_backgrounds_pos_no_shape
\to \everytabulate

%D Beware, the following code is somewhat weird and experimental and might be
%D dropped or become a loadable module.

%D \macros
%D   {GFC, GTC, GSC}
%D
%D The next macros extend tables and tabulation with backgrounds and position
%D related features. Areas are specified with symbolic names, and symbolic
%D references to the graphics involved. Each table has its own namespace.

\newconditional\tablehaspositions
\newcount      \noftabpositions
\newtoks       \posXCtoks

\unexpanded\def\anch_tabulate_bpos{\bpos}
\unexpanded\def\anch_tabulate_epos{\epos}

\installcorenamespace{positiontables}

\def\tbPOSprefix
  {\??positiontables\number\noftabpositions:}

\def\tablepos
  {\normalexpanded{\global\posXCtoks\emptytoks\the\posXCtoks}}

\let\tabulatepos\tablepos

\unexpanded\def\tbXC {\dosingleempty\anch_tables_XC }
\unexpanded\def\tbGSC{\dosingleempty\anch_tables_GSC}
\unexpanded\def\tbGFC{\dosingleempty\anch_tables_GFC}
\unexpanded\def\tbGTC{\dosingleempty\anch_tables_GTC}

\def\anch_table_check_state
  {\iftrialtypesetting
     \global\settrue\tablehaspositions
     \firstargumentfalse
   \fi}

\def\anch_tables_XC [#1]{\anch_table_check_state\iffirstargument\anch_tables_indeed_XC [#1]\else\expandafter\NC\fi}
\def\anch_tables_GSC[#1]{\anch_table_check_state\iffirstargument\anch_tables_indeed_GSC[#1]\else\expandafter\NC\fi}
\def\anch_tables_GFC[#1]{\anch_table_check_state\iffirstargument\anch_tables_indeed_GFC[#1]\else\expandafter\NC\fi}
\def\anch_tables_GTC[#1]{\anch_table_check_state\iffirstargument\anch_tables_indeed_GTC[#1]\else\expandafter\NC\fi}

\def\anch_tables_indeed_XC[#1]%
  {{\let\NC\relax\processcommalist[#1]\anch_tables_step_XC}}

\def\anch_tables_step_XC#1%
  {\anch_tables_step_indeed_XC[#1]}

\def\anch_tables_step_indeed_XC[#1#2]%
  {\if#1>\anch_tables_indeed_GFC  [#2:#2]\else
   \if#1+\anch_tables_indeed_GFC  [#2:#2]\else
   \if#1<\anch_tables_indeed_GTC  [#2:#2]\else
   \if#1-\anch_tables_indeed_GTC  [#2:#2]\else
   \if#1=\anch_tables_indeed_GSC  [#2:#2]\else
         \anch_tables_indeed_GSC[#1#2:#1#2]\fi\fi\fi\fi\fi}

\def\anch_tables_indeed_GSC[#1]%
  {\processcommalist[#1]\anch_tables_step_GSC}

\def\anch_tables_step_GSC#1%
  {\anch_tables_append_GSC[#1:#1]}

\def\anch_tables_append_GSC[#1:#2:#3]%
% {\doglobal\appendtoks\anch_tables_process_GSC[#1:#2]\to\posXCtoks\NC}
  {\gtoksapp\posXCtoks{\anch_tables_process_GSC[#1:#2]}\NC}

\def\anch_tables_process_GSC[#1:#2]%
  {\remappositionframed{#2}{\tbPOSprefix#1}%
   \anch_tabulate_bpos{\tbPOSprefix#1}%
   \doglobal\appendtoks\expandafter\anch_tabulate_epos\expandafter{\tbPOSprefix#1}\to\posXCtoks}
%  \xtoksapp\posXCtoks{\anch_tabulate_epos{\tbPOSprefix#1}}}

\def\anch_tables_indeed_GFC[#1]%
  {\doglobal\appendtoks\anch_tables_delayed_GFC[#1]\to\posXCtoks\NC}
% {\gtoksapp\posXCtoks{\anch_tables_delayed_GFC[#1]}\NC}

\def\anch_tables_delayed_GFC[#1]%
  {\processcommalist[#1]\anch_tables_step_GFC}

\def\anch_tables_step_GFC#1%
  {\anch_tables_process_GFC[#1:#1]}

\def\anch_tables_process_GFC[#1:#2:#3]%
  {\remappositionframed{#2}{\tbPOSprefix#1}%
   \anch_tabulate_bpos{\tbPOSprefix#1}}

\def\anch_tables_indeed_GTC[#1]%
  {\doglobal\appendtoks\anch_tables_delayed_GTC[#1]\to\posXCtoks\NC}
% {\gtoksapp\posXCtoks{\anch_tables_delayed_GTC[#1]}\NC}

\def\anch_tables_delayed_GTC[#1]%
  {\doglobal\appendtoks\anch_tables_process_GTC[#1]\to\posXCtoks}
% {\gtoksapp\posXCtoks{\anch_tables_process_GTC[#1]}\NC}

\def\anch_tables_process_GTC[#1]%
  {\processcommalist[#1]\anch_tables_step_GTC}

\def\anch_tables_step_GTC#1%
  {\anch_tables_step_indeed_GTC[#1:#1]}

\def\anch_tables_step_indeed_GTC[#1:#2]%
  {\anch_tabulate_epos{\tbPOSprefix#1}}

%D The amount of code to support tables and tabulation is rather
%D minimalistic.

\let\tabulatepos\tablepos

\def\tabulatenormalpos
  {\iftrialtypesetting
     % nothing
   \else\ifconditional\tablehaspositions
     \hss\tabulatepos\hss
   \else
     % nothing
   \fi\fi}

\def\tabulateequalpos
  {\iftrialtypesetting
     \tabulateEQ
   \else\ifconditional\tablehaspositions
     \tabulateEQpos
   \else
     \tabulateEQ
   \fi\fi}

\def\tabulateEQpos
  {\setbox\scratchbox\hbox{\tabulateEQ}%
   \hbox to \wd\scratchbox{\hss\kern\zeropoint\tabulatepos\hss}% hpack
   \kern-\wd\scratchbox
   \box\scratchbox}

\appendtoks
    \global\advance\noftabpositions\plusone
    \global\setfalse\tablehaspositions
\to \everytabulate

% We need to handle paragraphs as well.

\let\anch_tabulate_flush_epos\relax

\unexpanded\def\anch_tabulate_bpos_indeed
  {\bpos}

\unexpanded\def\anch_tabulate_epos_indeed#1%
  {\ifvoid\b_tabl_tabulate_current\c_tabl_tabulate_column
     \epos{#1}%
     \glet\anch_tabulate_flush_epos\relax
   \else
     \gdef\anch_tabulate_flush_epos{\epos{#1}}%
   \fi}

\def\flushtabulatesplitbox
  {\box\b_tabl_tabulate
   \iftrialtypesetting\else\ifconditional\tablehaspositions\anch_tabulate_flush_epos\fi\fi}

\appendtoks
    \let\anch_tabulate_bpos\anch_tabulate_bpos_indeed % ?
    \let\anch_tabulate_epos\anch_tabulate_epos_indeed % ?
    \glet\anch_tabulate_flush_epos\relax
\to \everytabulate

%D In order to prevent potential clashes with abbreviations, postpone the mapping.

\appendtoks
    \let\GSC\tbGSC
    \let\GFC\tbGFC
    \let\GTC\tbGTC
    \let\XC \tbXC
\to \everytabulate

%D \macros
%D   {definepositionframed}
%D
%D The next example show how to provide backgrounds to table cells. First we define
%D some framed backgrounds.
%D
%D \startbuffer
%D \definepositionframed[x][background=color,backgroundcolor=red]
%D \definepositionframed[y][background=color,backgroundcolor=green]
%D \definepositionframed[z][background=color,backgroundcolor=blue]
%D \stopbuffer
%D
%D \typebuffer
%D
%D % \getbuffer
%D
%D \startbuffer
%D \starttabulate[|c|c|c|]
%D \GFC[f:x] this is a small  \NC       table            \NC     in which we \NC \FR
%D \NC       will demonstrate \GFC[g:z] that this        \GTC[g] positioning \NC \MR
%D \GSC[e:y] mechanism also   \GTC[f]   works quite well \NC     in tables   \NC \LR
%D \stoptabulate
%D \stopbuffer
%D
%D The table itself defines three areas (a, b and~c) using these frames.
%D
%D \typebuffer
%D % \getbuffer
%D
%D Tables (based on \TABLE) are supported by:

\def\normalTABLEsimplebar {\unskip\!ttRightGlue&\tablepos&}                       % |
\def\normalTABLEcomplexbar{\unskip\!ttRightGlue&\omit\tablepos\!ttAlternateVrule} % \|
\def\normalTABLEquote     {\unskip\!ttRightGlue&\omit\tablepos&}                  % "

\appendtoks
    \global\advance\noftabpositions\plusone
    \global\setfalse\tablehaspositions
\to \everytable

%D Since we don't want nameclashes:

\appendtoks
    \let\GSC\tbGSC
    \let\GFC\tbGFC
    \let\GTC\tbGTC
    \let\XC \tbXC
\to \everytable

%D In the previous example, we could have provided an overlay to the framed definition.
%D A more direct approach is demonstrated below:
%D
%D \startbuffer
%D \def\cw#1{\color[white]{#1}}
%D
%D \startMPpositiongraphic{tableshade}
%D   initialize_area(\MPpos{\MPvar{from}},\MPpos{\MPvar{to}}) ;
%D   color c ; c := \MPvar{color} ;
%D   linear_shade(pxy,0,.4c,.9c) ;
%D   anchor_area(\MPanchor{\MPvar{from}}) ;
%D \stopMPpositiongraphic
%D
%D \setMPpositiongraphic{b:x}{tableshade}{from=b:x,to=e:x,color=red}
%D \setMPpositiongraphic{b:y}{tableshade}{from=b:y,to=e:y,color=green}
%D \setMPpositiongraphic{b:z}{tableshade}{from=b:z,to=e:z,color=blue}
%D \stopbuffer
%D
%D \typebuffer \getbuffer
%D
%D The definition of the table looks about the same as the previous one:
%D
%D \startbuffer
%D \starttable[|c|c|c|]
%D \GFC[b:z] \cw{this is a small}  \NC       \cw{table}            \NC     in which we      \NC \FR
%D \NC       \cw{will demonstrate} \GFC[c:y] \cw{that this}        \GTC[c] \cw{positioning} \NC \MR
%D \GSC[a:x] \cw{mechanism also}   \GTC[b]   \cw{works quite well} \NC     in tables        \NC \LR
%D \stoptable
%D \stopbuffer
%D
%D \typebuffer
%D
%D \getbuffer

% \definepositionframed[w][background=color,backgroundcolor=yellow]
% \definepositionframed[x][background=color,backgroundcolor=red]
% \definepositionframed[y][background=color,backgroundcolor=green]
% \definepositionframed[z][background=color,backgroundcolor=blue]
%
% \starttabulate[|c|c|c|]
% \NC this is a small  \NC table            \NC in which we \NC \FR
% \NC will demonstrate \NC that this        \NC positioning \NC \MR
% \NC mechanism also   \NC works quite well \NC in tables   \NC \LR
% \stoptabulate
%
% \starttabulate[|c|c|c|]
% \GFC[f:x] this is a small      \GTC      table            \NC     in which we \NC \FR
% \NC       will demonstrate     \GFC[g:z] that this        \GTC[g] positioning \NC \MR
% \GSC[e:y] mechanism also       \GTC[f]   works quite well \NC     in tables   \NC \LR
% \stoptabulate
%
% \starttabulate[|c|c|c|]
% \GFC[f:x,d:w] this is a small  \GTC[d]   table            \NC     in which we \NC \FR
% \NC           will demonstrate \GFC[g:z] that this        \GTC[g] positioning \NC \MR
% \GSC[e:y]     mechanism also   \GTC[f]   works quite well \NC     in tables   \NC \LR
% \stoptabulate
%
% \starttabulate[|c|c|c|]
% \XC[+f:x] this is a small  \XC      table            \NC     in which we \NC \FR
% \NC      will demonstrate  \XC[+g:z] that this       \XC[-g] positioning \NC \MR
% \XC[=e:y] mechanism also   \XC[-f]  works quite well \NC     in tables   \NC \LR
% \stoptabulate
%
% \starttabulate[|c|c|c|]
% \XC[+f:x,+d:w] this is a small  \XC[-d]   table            \NC     in which we \NC \FR
% \NC            will demonstrate \XC[+g:z] that this        \XC[-g] positioning \NC \MR
% \XC[=e:y]       mechanism also  \XC[-f]   works quite well \NC     in tables   \NC \LR
% \stoptabulate

% evt                  [b:x]
%
% \definepositionframed[x][background=color,fillcolor=red]
% \definepositionframed[y][background=color,fillcolor=green]
% \definepositionframed[z][background=color,fillcolor=blue]

\unexpanded\def\remappositionframed#1#2% from to
  {\copyposition{b:#1}{b:#2}%
   \copyposition{e:#1}{e:#2}%
   \anch_positions_set_action{b:#2}{\dopositionaction{b:#1}}}

\unexpanded\def\definepositionframed
  {\dodoubleargument\anch_framed_define}

\def\anch_framed_define[#1][#2]%
  {\anch_positions_set_action{b:#1}{\anch_framed_handle[#1][#2]}}

\unexpanded\def\anch_framed_handle
  {\bgroup
   \anch_framed_indeed}

\unexpanded\def\positionframed
  {\bgroup
   \dodoubleempty\anch_framed_indeed}

\def\anch_framed_indeed[#1][#2]%
  {\setbox\scratchbox\hpack
     {\scratchwidth \dimexpr\MPx{e:#1}-\MPx{b:#1}\relax
      \scratchdepth \dimexpr\MPy{b:#1}-\MPy{e:#1}+\MPd{e:#1}\relax
      \scratchheight\dimexpr\scratchdepth+\MPh{b:#1}\relax
      \lower\scratchdepth\hpack
        {\framed[\c!width=\scratchwidth,\c!height=\scratchheight,\c!offset=\v!overlay,#2]{}}}%
   \smashedbox\scratchbox
   \egroup}

\protect \endinput