%D \module
%D   [       file=attr-ini,
%D        version=2007.06.06,
%D          title=\CONTEXT\ Attribute Macros,
%D       subtitle=Initialization,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright=PRAGMA-ADE]
%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 Attribute Macros / Initialization}

%D Although it's still somewhat experimental, here we introduce code
%D related to attributes.

\unprotect

\registerctxluafile{attr-ini}{1.001}

\def\pushattribute#1%
  {\global\advance\csname\??ae:\string#1\endcsname\plusone
   \global\expandafter\mathchardef\csname\??ae:\string#1:\number\csname\??ae:\string#1\endcsname\endcsname\attribute#1}

\def\popattribute#1%
  {\attribute#1\csname\??ae:\string#1:\number\csname\??ae:\string#1\endcsname\endcsname
   \global\advance\csname\??ae:\string#1\endcsname\minusone}

\def\installattributestack#1%
  {\expandafter\newcount\csname\??ae:\string#1\endcsname}

\newtoks \attributesresetlist

\ifdefined \v!global \else \def\v!global{global} \fi % for metatex

\unexpanded\def\defineattribute
  {\dodoubleempty\dodefineattribute}

\def\dodefineattribute[#1][#2]% alternatively we can let lua do the housekeeping
  {\expandafter\newattribute\csname @attr@#1\endcsname
   \expandafter        \xdef\csname :attr:#1\endcsname{\number\lastallocatedattribute}%
   \ctxlua{attributes.define("#1",\number\lastallocatedattribute)}%
  %\writestatus\m!systems{defining attribute #1 with number \number\lastallocatedattribute}%
   \doifnotinset\v!global{#2}{\appendetoks\csname @attr@#1\endcsname\attributeunsetvalue\to\attributesresetlist}}

\unexpanded\def\definesystemattribute
  {\dodoubleempty\dodefinesystemattribute}

\def\dodefinesystemattribute[#1][#2]% alternatively we can let lua do the housekeeping
  {\scratchcounter\ctxlua{tex.print(attributes.private("#1"))}\relax
   \global\expandafter\attributedef\csname @attr@#1\endcsname\scratchcounter
          \expandafter        \xdef\csname :attr:#1\endcsname{\number\scratchcounter}%
  %\writestatus\m!systems{defining system attribute #1 with number \number\scratchcounter}%
   \doifnotinset\v!global{#2}{\appendetoks\csname @attr@#1\endcsname\attributeunsetvalue\to\attributesresetlist}}

% expandable so we can \edef them for speed

\def\dosetattribute#1#2{\csname @attr@#1\endcsname#2\relax}
\def\doresetattribute#1{\csname @attr@#1\endcsname\attributeunsetvalue}
\def\dogetattribute  #1{\number\csname @attr@#1\endcsname}
\def\dogetattributeid#1{\csname :attr:#1\endcsname}

\let\dompattribute\gobbletwoarguments

\def\resetallattributes{\the\attributesresetlist}

%D For the moment we put this here (later it will move to where it's used):

\definesystemattribute[state]
\definesystemattribute[skip]
\definesystemattribute[penalty]
\definesystemattribute[colormodel][global]                     \chardef\colormodelattribute     \dogetattributeid{colormodel}
\definesystemattribute[color]                                  \chardef\colorattribute          \dogetattributeid{color}
\definesystemattribute[transparency]                           \chardef\transparencyattribute   \dogetattributeid{transparency}
\definesystemattribute[background]                             \chardef\backgroundattribute     \dogetattributeid{background}
\definesystemattribute[colorintent]                            \chardef\colorintentattribute    \dogetattributeid{colorintent}
\definesystemattribute[negative]                               \chardef\negativeattribute       \dogetattributeid{negative}
\definesystemattribute[effect]                                 \chardef\effectattribute         \dogetattributeid{effect}
\definesystemattribute[viewerlayer]                            \chardef\viewerlayerattribute    \dogetattributeid{viewerlayer}
\definesystemattribute[layoutcomponent]                        \chardef\layoutcomponentattribute\dogetattributeid{layoutcomponent}
\definesystemattribute[reference]                              \chardef\referenceattribute      \dogetattributeid{reference}
\definesystemattribute[destination]                            \chardef\destinationattribute    \dogetattributeid{destination}
\definesystemattribute[graphicvadjust]                         \chardef\graphicvadjustattribute \dogetattributeid{graphicvadjust}
\definesystemattribute[ruled]                                  \chardef\ruledattribute          \dogetattributeid{ruled}
\definesystemattribute[shifted]                                \chardef\shiftedattribute        \dogetattributeid{shifted}

\protect \endinput