1 files changed, 94 insertions, 0 deletions
diff --git a/tex/context/base/page-ins.mkiv b/tex/context/base/page-ins.mkiv
new file mode 100644
index 000000000..3e12bfcf0
--- /dev/null
+++ b/tex/context/base/page-ins.mkiv
@@ -0,0 +1,94 @@
+%D \module
+%D   [       file=core-ins,
+%D        version=2002.04.16,
+%D          title=\CONTEXT\ Insertion Macros,
+%D       subtitle=Insertions,
+%D         author=Hans Hagen,
+%D           date=\currentdate,
+%D      copyright={PRAGMA / Hans Hagen \& Ton Otten}]
+%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 Core Macros / Insertions}
+
+%D Insertions are special data collections that are associated
+%D to \TEX's internal page builder. When multiple footnote
+%D classes were introduced, I decided to isolate some of the
+%D functionality in a module.
+
+\unprotect
+
+\newtoks\@@insertionlist
+
+\def\processinsertions{\the\@@insertionlist}
+
+\let\doprocessinsert\gobbleoneargument
+
+\def\installinsertion#1%
+  {\ifdefined#1\else
+     \let#1\relax
+   \fi
+   \ifx#1\relax % permits \csname...\endcsname
+     \newinsert#1%
+     \count#1\plusthousand
+     \skip #1\zeropoint
+     \dimen#1\maxdimen
+     \appendtoks\doprocessinsert#1\to\@@insertionlist
+   \fi}
+
+
+\def\synchronizeinsertions
+  {\def\doprocessinsert##1{\ifvoid##1\else\insert##1{\unvbox##1}\fi}%
+   \processinsertions}
+
+%D For instance, when we postpone footnotes, we need to save
+%D some data related to the inserts. The next methods are
+%D far from ideal, but better than nothing. We save and
+%D restore box content and associated data independently.
+%D The box content is only restores when non||void.
+
+\def\backupinsertion#1%
+  {\csname\string#1\endcsname}
+
+\def\installbackupinsertion#1%
+  {\expandafter\newinsert\csname\string#1\endcsname
+   \count\backupinsertion#1\zerocount
+   \skip \backupinsertion#1\zeropoint
+   \dimen\backupinsertion#1\maxdimen}
+
+\def\saveinsertionbox#1%
+  {\ifdim\ht#1>\zeropoint % hm, actually unknown
+     \global\setbox\backupinsertion#1\box#1%
+   \else
+     \global\setbox\backupinsertion#1\emptybox
+   \fi}
+
+\def\restoreinsertionbox#1%
+  {\ifvoid\backupinsertion#1\else % if void, we keep the content
+     \global\setbox#1\box\backupinsertion#1%
+   \fi}
+
+\def\eraseinsertionbackup#1%
+  {\global\setbox\backupinsertion#1\emptybox}
+
+\def\saveinsertiondata#1%
+  {\global\skip \backupinsertion#1\skip #1%
+   \global\count\backupinsertion#1\count#1%
+   \global\dimen\backupinsertion#1\dimen#1}
+
+\def\restoreinsertiondata#1%
+  {\global\skip #1\skip \backupinsertion#1%
+   \global\count#1\count\backupinsertion#1%
+   \global\dimen#1\dimen\backupinsertion#1}
+
+%D Auxiliary macros:
+
+\def\addinsertionheight#1\to#2%
+  {\ifvoid#1\else
+     \advance#2 1\skip#1\relax
+     \advance#2  \ht  #1\relax
+   \fi}
+
+\protect \endinput