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%D \module
%D   [       file=page-mis,
%D        version=2008.11.17, % was part of page-flt.tex / 2000.10.20
%D          title=\CONTEXT\ Page Macros,
%D       subtitle=Misc Float Things,
%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 Page Macros / Misc Float Things}

\registerctxluafile{page-mis}{1.001}

\unprotect

% postponing

\newevery\everytopofpage\relax

\appendtoks   \the\everytopofpage          \to\everystarttext
\appendtoks\global\everytopofpage\emptytoks\to\everystoptext

% \startpostponing [pagenumber] [+pageoffset]
%
% \startpostponing[2]
%   PAGE 2 \blank
% \stoppostponing
%
% \startpostponing[+1]
%   PAGE +1 \blank
% \stoppostponing
%
% \startpostponing[+2]
%   PAGE +2 \blank
% \stoppostponing
%
% \starttext \dorecurse{4}{\input tufte \page} \stoptext

%D There is no real need to use \LUA\ here but the bookkeeping
%D is somewhat easier and we also can erase buffers easier when
%D we keep a local cache, especially as we can flush per page.

\newif   \ifinpostponing                  % prevents nesting
\newcount\postponed_page_blocks_next_page % set at the lua end

\unexpanded\setvalue{\e!start\v!postponing}%
  {\bgroup
   \obeylines
   \doifnextoptionalelse{\egroup\postponed_page_block_start}{\egroup\postponed_page_block_start[0]}}

\unexpanded\setvalue{\e!stop\v!postponing}%
  {\ctxcommand{registerpostponedblock("\currentpostponedpage")}\relax}

\def\postponed_page_block_start[#1]%
  {\edef\currentpostponedpage{#1}%
   \dostartbuffer[postponedblock][\e!start\v!postponing][\e!stop\v!postponing]}

% officially we should flush again after a flush as there can be new future pages
% but that will be looked into when we run into it

\unexpanded\def\postponed_page_block_flush
  {\bgroup
   \inpostponingtrue                  % for old times sake
   \global\pagetotal\zeropoint        % here? still needed? (was after flush pagefloats)
   \the\everytopofpage\relax
  %\flushrestfloats
   \doflushpagefloats
   \setnormalcatcodes                 % postponing in verbatim
   \restoreglobalbodyfont             % otherwise problems inside split verbatim
   \ctxcommand{flushpostponedblocks()}%
   \relax
   \doflushfloats                     % new but potential dangerous, maybe we need a classification
   \egroup}                           % of blocks: with and without flush

\def\doflushpostponedblocks
  {\ifinpostponing
     % probably a nested flush
   \else\ifnum\postponed_page_blocks_next_page=\zerocount
     % nothing in cache
   \else\ifnum\postponed_page_blocks_next_page<\zerocount
     % generic cache
     \postponed_page_block_flush
   \else\ifnum\postponed_page_blocks_next_page>\realpageno
     % future content
   \else
     % pending content
     \postponed_page_block_flush
   \fi\fi\fi\fi}

\def\doflushpostponedcontent % called in page-one
  {\bgroup
   \setsystemmode\v!postponing
   \the\everytopofpage
  %\flushrestfloats
   \doflushpagefloats
   \doflushpostponedblocks
   \egroup}

\protect \endinput