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diff --git a/tex/context/base/supp-mrk.tex b/tex/context/base/supp-mrk.tex new file mode 100644 index 000000000..287d4bbec --- /dev/null +++ b/tex/context/base/supp-mrk.tex @@ -0,0 +1,299 @@ +%D \module
+%D [ file=supp-mrk,
+%D version=1995.10.10,
+%D title=\CONTEXT\ Support Macros,
+%D subtitle=Marks,
+%D author=Jim Fox / 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. Non||commercial use is
+%C granted.
+
+%D There are 256 \COUNTERS, \DIMENSIONS, \SKIPS, \MUSKIPS\ and
+%D \BOXES, 16~in- and output buffers, but there is only one
+%D \MARK. In TugBoat~8 (1987, no~1) Jim Fox presents a set of
+%D macros that can be used to mimmick multiple marks. We
+%D gladly adopt them here.
+
+\writestatus{loading}{Context Support Macros / Marks}
+
+\unprotect
+
+%D This implementation is more or less compatible with the
+%D other register macros in \PLAIN\ \TEX. A mark is defined by:
+%D
+%D \starttypen
+%D \newmark\name
+%D \stoptypen
+%D
+%D and can be called upon with:
+%D
+%D \starttypen
+%D \topname
+%D \botname
+%D \firstname
+%D \stoptypen
+%D
+%D The only drawback of his approach is that the marks must be
+%D preloaded in the output routine. This is accomplished by
+%D means of:
+%D
+%D \starttypen
+%D \getmarks\name
+%D \stoptypen
+%D
+%D The macros presented here are in most aspects copies of
+%D those presented by Jim Fox. We've taken the freedom to
+%D change a few things for more or less obvious reasons:
+%D
+%D \startopsomming
+%D \som Because the original macros look quite complicated,
+%D which is mainly due to extensive use of
+%D \type{\expandafter}'s and \type{\csname}'s, we changed
+%D those in favor of \type{\getvalue}.
+%D \som To be more in line with the rest of \CONTEXT, we've
+%D changed some of the names of macros.
+%D \som Because we are already short on \COUNTERS\ we use
+%D macros when possible.
+%D \som We maintain a list of defined marks and use one
+%D call for getting them all at once.
+%D \som We have extended the mechanism to splitmarks (not
+%D perfected yet).
+%D \som We've introduced optional expansion of the contents
+%D of marks.
+%D \stopopsomming
+%D
+%D Whatever changes we've made, the credits still go to Jim,
+%D whatever goes wrong is due to me. The method is described
+%D in the TugBoat mentioned before, so we won't go into
+%D details. All marks belonging to a group are packed in a
+%D list. In this list they are preceded by a macro that can
+%D be defined at will and a number concerning the position at
+%D which it was defined.
+%D
+%D \starttypen
+%D \def\somelist{... \domark5{this} ... \domark31{that} ...}
+%D \stoptypen
+%D
+%D The original \type{\mark} keeps track of the number and
+%D \type{\topmark} and \type{\botmark} are used to extract the
+%D actual marks from the list. The counting is done by
+%D
+%D \starttypen
+%D \currentmarker
+%D \stoptypen
+%D
+%D In \CONTEXT\ we use the mark mechanism to keep track of
+%D colors. In a complicated documents with many colors per
+%D page, \type{\currentmarker} can therefore get pretty high.
+%D (Well, this is not completely true, because we don't
+%D always have to use marks.)
+
+\newcount\currentmarker
+
+%D The original implementation used a few more \COUNTERS. Two
+%D have been substituted by macros, one has been replaced by
+%D our scratch counter.
+%D
+%D \starttypen
+%D % \newcount\topmarker
+%D % \newcount\botmarker
+%D % \newcount\foundmarker
+%D \stoptypen
+%D
+%D We've also introduced some constants, one for the lists and
+%D three for composing the mark commands.
+
+\def\@@marklist@@ {marklist}
+\def\@@marktop@@ {top}
+\def\@@markbot@@ {bot}
+\def\@@markfirst@@ {first}
+
+%D The next one is new too. All defined marks are packed in a
+%D comma seperated list. This could of course have been a token
+%D list but \CONTEXT\ has some preference for comma lists.
+
+\def\markers {}
+
+%D \macros
+%D {expandmarks}
+%D {}
+%D
+%D There are two booleans. The first one handles the first
+%D marks, the second concerns expansion. This second one is
+%D new.
+
+\newif\ifnofirstmarker
+\newif\ifexpandmarks \expandmarkstrue
+
+%D We use an indirect call to the mack mechanism.
+
+\let\normalmark = \mark
+\let\normaltopmark = \topmark
+\let\normalbotmark = \botmark
+\let\normalfirstmark = \firstmark
+\let\normalsplitbotmark = \splitbotmark
+\let\normalsplitfirstmark = \splitfirstmark
+
+%D The next macro replaces the multiple step expansion and
+%D command name constructors of Jim. This alternative leads to
+%D a more readable source (we hope).
+
+\def\makemarknames#1%
+ {\bgroup
+ \escapechar=-1
+ \xdef\markname{\string#1}%
+ \xdef\marklist{\@@marklist@@\string#1}%
+ \egroup}
+
+%D \macros
+%D {newmark}
+%D {}
+%D
+%D A mark is defined by \type{\newmark}. At the same time,
+%D the name of the mark is added to a commalist. The
+%D three initializations were not in the original design, but
+%D make calls from outside the output routine a bit more
+%D robust.
+
+\def\newmark#1%
+ {\bgroup
+ \makemarknames{#1}%
+ \doglobal\addtocommalist{\markname}\markers%
+ \long\setgvalue{\@@marktop@@\markname}{}%
+ \long\setgvalue{\@@markfirst@@\markname}{}%
+ \long\setgvalue{\@@markbot@@\markname}{}%
+ \setgvalue{\marklist}{\domark0{}}%
+ \long\gdef#1{\addmarker#1}%
+ \egroup}
+
+%D Setting a new mark and adding a mark to the designated
+%D list is done by \type{\addmarker}. This is an internal
+%D command, the user set a marks bij calling it's name:
+%D
+%D \starttypen
+%D \mymark{some text}
+%D \stoptypen
+%D
+%D Where \type{\mymark} is previously defined by
+%D \type{\newmark}.
+
+\long\def\addmarker#1#2%
+ {\bgroup
+ \makemarknames{#1}%
+ \global\advance\currentmarker by 1\relax
+ \normalmark{\the\currentmarker}%
+ \@EA\!!toksa\@EA=\@EA\@EA\@EA{\csname\marklist\endcsname}%
+ \ifexpandmarks
+ \setxvalue{\marklist}%
+ {\the\!!toksa
+ \noexpand\domark
+ \the\currentmarker{#2}}%
+ \else
+ \!!toksb=\@EA{#2}%
+ \setxvalue{\marklist}%
+ {\the\!!toksa
+ \noexpand\domark
+ \the\currentmarker{\the\!!toksb}}%
+ \fi
+ \egroup}
+
+%D \macros
+%D {getmarks,getallmarks,
+%D getsplitmarks,getallsplitmarks}
+%D {}
+%D
+%D In fact, marks make only sense in the output routine. Marks
+%D are derived from their list by means of \type{\getmarks}.
+%D Only one call per mark is permitted in the output routine.
+%D Therefore, it's far more easy to get them all at once, by
+%D means of \type{\getallmarks}, which is not part of the
+%D original design.
+%D
+%D This grabbing is done by processing the list using the
+%D embedded \type{\domark} macros. When a relevant mark is
+%D found, this macro is reassigned and from then on serves
+%D in building the new list.
+
+\def\getmarks#1%
+ {\bgroup
+ \makemarknames{#1}%
+ \edef\topmarker{0\normaltopmark}%
+ \edef\botmarker{0\normalbotmark}%
+ \!!toksb={}%
+ \nofirstmarkertrue
+ \let\@fi=\fi \let\fi=\relax
+ \let\@or=\or \let\or=\relax
+ \let\@else=\else \let\else=\relax
+ \let\domark=\doscanmarks
+ \getvalue{\marklist}\lastmark
+ %\message{markstatus : [\the\!!toksa\the\!!toksb\the\!!toksc]}%
+ \long\setxvalue{\marklist}{\the\!!toksa\the\!!toksb\the\!!toksc}%
+ \egroup}
+
+\def\getallmarks%
+ {\processcommacommand[\markers]\getmarks}
+
+\def\getsplitmarks#1%
+ {\bgroup
+ \makemarknames{#1}%
+ \@EA\let\@EA\savedmarklist\@EA=\csname\marklist\endcsname
+ \edef\topmarker{0\normalsplitfirstmark}%
+ \edef\botmarker{0\normalsplitbotmark}%
+ \!!toksb={}%
+ \nofirstmarkertrue
+ \let\@fi=\fi \let\fi=\relax
+ \let\@or=\or \let\or=\relax
+ \let\@else=\else \let\else=\relax
+ \let\domark=\doscanmarks
+ \getvalue{\marklist}\lastmark
+ \@EA\global\@EA\let\csname\marklist\endcsname=\savedmarklist
+ \egroup}
+
+\def\getallsplitmarks%
+ {\processcommacommand[\markers]\getsplitmarks}
+
+\long\def\dodoscanmarks#1%
+ {\ifnum\scratchcounter>\topmarker\relax
+ \@else
+ \long\setgvalue{\@@marktop@@\markname}{#1}%
+ \@fi
+ \ifnum\scratchcounter>\botmarker\relax
+ \let\domark=\dorecovermarks
+ \!!toksb=\@EA{\@EA\domark\the\scratchcounter{#1}}%
+ \@else
+ \ifnofirstmarker
+ \long\setgvalue{\@@markfirst@@\markname}{#1}%
+ \ifnum\scratchcounter>\topmarker\relax
+ \nofirstmarkerfalse
+ \@fi
+ \@fi
+ \long\setgvalue{\@@markbot@@\markname}{#1}%
+ \!!toksa=\@EA{\@EA\domark\the\scratchcounter{#1}}%
+ \@fi}
+
+\def\doscanmarks%
+ {\afterassignment\dodoscanmarks\scratchcounter=}
+
+\long\def\dorecovermarks#1\lastmark%
+ {\!!toksc={\domark#1}}
+
+\def\lastmark%
+ {\!!toksc={}}
+
+%D No watch what happens next. Because we used an indirect
+%D call to the mark mechanism we can redefine the original
+%D \type{\mark} command.
+
+\newmark\mark
+
+%D One final advice. Use marks with care. When used in globally
+%D assigned boxes, the list can grow quite big, and processing
+%D can slow down considerably.
+
+\protect
+
+\endinput
+
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