%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 \& \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 Attribute Macros / Initialization}

%D Although it's still somewhat experimental, here we introduce code
%D related to attributes. Housekeeping will move completely to \LUA\
%D and \type {\newattribute} will go away.

\unprotect

\registerctxluafile{attr-ini}{1.001}

\installcorenamespace{attributecount}  % the counter representing the attribute (attrdef'd)
\installcorenamespace{attributeid}     % the internal number
\installcorenamespace{attributestack}  % the attribute specific stack

\unexpanded\def\pushattribute#1%
  {\global\advance\csname\??attributestack\string#1\endcsname\plusone
   \expandafter\xdef\csname\??attributestack\string#1:\number\csname\??attributestack\string#1\endcsname\endcsname{\number\attribute#1}}

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

\unexpanded\def\installattributestack#1%
  {\ifcsname\??attributestack\string#1\endcsname \else
     \expandafter\newcount\csname\??attributestack\string#1\endcsname
   \fi}

\newtoks \attributesresetlist

\ifdefined \s!global \else \def\s!global{global} \fi % for metatex % or hard check later
\ifdefined \s!public \else \def\s!public{public} \fi % for metatex % or hard check later

\unexpanded\def\defineattribute
  {\dodoubleempty\attr_basics_define}

\def\attr_basics_define[#1][#2]% alternatively we can let lua do the housekeeping
  {\expandafter\newattribute\csname\??attributecount#1\endcsname
   \expandafter\newconstant \csname\??attributeid#1\endcsname
   \csname\??attributeid#1\endcsname\c_syst_last_allocated_attribute
   \ctxcommand{defineattribute("#1",\number\c_syst_last_allocated_attribute)}%
   \doifnotinset\s!global{#2}{\appendetoks\csname\??attributecount#1\endcsname\attributeunsetvalue\to\attributesresetlist}%
   \doifinset   \s!public{#2}{\expandafter\let\csname#1attribute\expandafter\endcsname\csname\??attributeid#1\endcsname}}

\unexpanded\def\definesystemattribute
  {\dodoubleempty\attr_basics_define_system}

\def\attr_basics_define_system[#1][#2]% alternatively we can let lua do the housekeeping
  {\scratchcounter\ctxcommand{getprivateattribute("#1")}\relax
   \expandafter\attributedef\csname\??attributecount#1\endcsname\scratchcounter
   \expandafter\newconstant \csname\??attributeid#1\endcsname
   \csname\??attributeid#1\endcsname\scratchcounter
  %\writestatus\m!system{defining system attribute #1 with number \number\scratchcounter}%
   \doifnotinset\s!global{#2}{\appendetoks\csname\??attributecount#1\endcsname\attributeunsetvalue\to\attributesresetlist}%
   \doifinset   \s!public{#2}{\expandafter\let\csname#1attribute\expandafter\endcsname\csname\??attributeid#1\endcsname}}

% expandable so we can \edef them for speed

\def\dosetattribute#1#2{\csname\??attributecount#1\endcsname#2\relax}
\def\doresetattribute#1{\csname\??attributecount#1\endcsname\attributeunsetvalue}
\def\dogetattribute  #1{\number\csname\??attributecount#1\endcsname}
\def\dogetattributeid#1{\number\csname\??attributeid#1\endcsname}

\let\dompattribute\gobbletwoarguments

\unexpanded\def\resetallattributes{\the\attributesresetlist}

%D Rather special.

\unexpanded\def\savecurrentattributes   #1{\ctxcommand{savecurrentattributes   ("#1")}}
\unexpanded\def\restorecurrentattributes#1{\ctxcommand{restorecurrentattributes("#1")}}

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

\definesystemattribute [state]
\definesystemattribute [color]           [public]
\definesystemattribute [colormodel]      [public,global]
\definesystemattribute [skip]
\definesystemattribute [penalty]
\definesystemattribute [transparency]    [public]
\definesystemattribute [background]      [public]
\definesystemattribute [alignbackground] [public]
\definesystemattribute [colorintent]     [public]
\definesystemattribute [negative]        [public]
\definesystemattribute [effect]          [public]
\definesystemattribute [viewerlayer]     [public]
\definesystemattribute [layoutcomponent] [public]
\definesystemattribute [reference]       [public]
\definesystemattribute [destination]     [public]
\definesystemattribute [internal]        [public]
\definesystemattribute [ruled]           [public]
\definesystemattribute [shifted]         [public]

\unexpanded\def\showattributes{\ctxcommand{showattributes()}}

\protect \endinput
