%\iffalse
%
% File calendar.dtx
% Copyright (C) 1996, 1997 by Frank Bennett.  All rights reserved.
%
% IMPORTANT NOTICE:
% You are not allowed to change this file.  You may however copy
% this file to a file with a different name and then change the
% copy if (a) you do not charge for the modified code, (b) you
% acknowledge the author(s) in the new file, if it
% is distributed to others, and (c) you attach these same
% conditions to the new file.
% 
% You are not allowed to distribute this file alone.  You are not
% allowed to take money for the distribution or use of this file
% (or a changed version) except for a nominal charge for copying
% etc.
% 
% You are allowed to distribute this file under the condition that
% it is distributed with all of its contents, intact.
% 
% For error reports, or offers to help make Calendar a more powerful,
% friendlier, and altogether more thrilling package, please contact me on
% fb@soas.ac.uk
% 
%<*dtx>
          \ProvidesFile{calendar.dtx}
%</dtx>
%<style>\NeedsTeXFormat{LaTeX2e}[1995/06/01]
%<style>\ProvidesPackage{calendar}
%<style>          [1998/01/17 18:14:52 3.1.1.1 Calendar engine (Frank Bennett)]
% \fi
%
% \def\fileversion{3.1.1.1}
% \def\filedate{1998/01/17 18:14:52}
%
%
% \iffalse
%<*driver>
\documentclass{ltxdoc}
%\usepackage[dvips]{color}
%\CodelineIndex
%\EnableCrossrefs
%\RecordChanges
\begin{document}
\OnlyDescription    % Comment out for implementation details
\DocInput{calendar.dtx}
\end{document}
%</driver>
% \fi
%
% \changes{v0.01}{1996/11/10}{Initial Version}
% \changes{v0.02}{1996/11/11}{Replaced \TeX{} newcount with \LaTeXe{}
% newcounter, and changed counters accordingly.}
% \changes{v0.02}{1996/11/11}
%    {Incorporated higher maths functions into an option declaration
%  in the main file (was loaded from a separate file in original
%  \TeX{} version.)}
% \changes{v0.03}{1996/11/12}{Complete re-draft of recursing routines,
%   with documentation.}
% \changes{v0.03}{1996/11/12}{Drafting of the sort engine.}
% \changes{v0.03}{1996/11/12}{Picked up some more counters that
%   hadn't been converted to \LaTeXe format.}
% \changes{v0.03}{1996/11/12}{Wholesale cutting of old recursing
%   and formatting routines.  The package is now a background engine;
%   it knows nothing about printing anymore.}
% \changes{v0.04}{1996/11/17}{Introduction of parsing routines
%   and reorganization of entire package.}
% \changes{v0.05}{1996/11/25}{Completed new parsing routines and finished
%   debugging of same.}
% \changes{v0.05}{1996/11/25}{Completed sorting routines and finished
%   debugging of same.}
% \changes{v0.06}{1996/11/27}{Added support for indicating a range of
%   dates in an input file, and for declaring recursive entries.}
% \changes{v0.07}{1996/11/27}{Minor alterations to make the package
%   work for the timesheets demo.  Another alpha release.}
% \changes{v0.08}{1996/11/27}{No changes to this file; but the
%   README shipped to CTAN was for Nelson Beebe's makeindex.  Ah,
%   the wonders of automation...}
% \changes{v0.09}{1996/11/29}{Added maths routines for weekly
%   and monthly recursion.  Nearly finished!}
% \changes{v0.10}{1996/11/29}{Various bug fixes.}
% \changes{v0.10}{1996/11/29}{Added routines for handling comments
%   in CLD files.  Added demonstration files and comments thereto.}
% \changes{v0.11}{1996/12/04}{Enhanced input and parsing routine.
%   Now handles entries across multiple lines, even with par, and does
%   not make characters active outside of the parsed text.}
% \changes{v0.11}{1996/12/04}{Provided a check to prevent multiple
%   input of data files.  Necessary to provide support for groups
%   of lists.}
% \changes{v0.11}{1996/12/06}{Further work on the initial input
%   code, to provide for groups of lists and groups of groups.
%   This portion of the code is now complete.}
% \changes{v0.11}{1996/12/07}{Code clean-up in the date parsing
%   routine; the code must be reasonably transparent if it is
%   to be used as a general date parsing engine in the package.}
% \changes{v0.12}{1996/12/15}{Complete redraft commenced following the
%   removal of the overword and dates code to separate
%   eponymous packages.  Recursive interface macro completed and
%   first cut of debugging done.  Released with the Thumbnail demo.}
% \changes{v1.0}{1996/12/26}{Far too many changes to document here.
%   Finished through to final, hopefully stable form, and packaged
%   with demonstration sub-packages for CTAN release.}
% \changes{v1.11}{1997/01/07}{Moved LoadClass declaration from
%   bottom of the timesht.cls file to the top, so that margin
%   adjustments would not be overwritten and options would take effect.}
% \changes{v1.11}{1997/01/07}{Added newpage to group break in timesheets style
%   file.}
% \changes{v1.12}{1997/01/18}{Fixed bug in the timesheets package that often caused
%  one line in any *.cld entry spanning a range of times to appear in the wrong place.
%  The ending, rather than the starting minutes of the range were used to calculate
%  the current time position within the timesheet.  Oops.  This bug was reported by Miroslav Novak.}
% \changes{v1.12}{1997/01/18}{Added code to correct another infelicity pointed
%   out by Miroslav Novak; the appearance of an item description line in timesheet
%   boxes where the ending time of the range for the item 
%   is the starting time of the range in the box.}
% \changes{v1.13}{1997/01/30}{Began work on improved
%   documentation.  No promises that this will happen quickly\ldots}
% \changes{v1.13}{1997/02/01}{Added color package to timesheets demo file.}
% \changes{v1.13}{1997/02/01}{Added  reference to need for color package
%  to documentation.}
% \changes{v1.14}{1997/02/12}{Corrected an error lurking in cal@text@init
%  (which turned out to be unused code --- the error cropped up when
%  the code was extracted for explicit invocation in the Monthly style)
%  that swallowed all event text when color was not in force, and gave
%  rise to a fatal error otherwise.  Oops.}
% \changes{v1.14}{1997/02/16}{Caught initialization of blank (but
%   non-empty) entries in \texttt{cal@print@format}.}
% \changes{v1.14}{1997/02/20}{Cut subpackages from this file;
%   too many packages now to for this to be manageable.}
% \changes{v1.14}{1997/02/21}{Eliminated erroneous use of
%   cal@read for inputting *.eve files.}
% \changes{v1.14}{1997/02/21}{Eliminated extraneous argument
%   to PackageWarning.}
% \changes{v1.14}{1997/02/21}{Added comment chars to the end
%   of exported *.eve file event entries.}
% \changes{v1.14}{1997/02/21}{Added initalization of exception
%   list and cal@append instruction to load events drawn from
%   an *.eve file into memory.  We now have phases of the moon.}
% \changes{v1.14}{1997/02/21}{Not a change, but a note of a bug.
%   A function such as moon.cld should be allowed to dynamically
%   change a function, and have the change register in the
%   theshorttext or thelongtext macros as the function recurses.
%   But the moon.cld phases only change on export, not during
%   the first run.}
% \changes{v1.14}{1997/02/22}{Added cal@dates@base and the
%   \texttt{z} incrementing option.  This gives us vertical
%   date columns without much work.  For use in a conference
%   style package for Miroslav Novak.}
% \changes{v1.14}{1997/02/23}{Added quick but very ugly
%   patch to allow non-printing text to be dropped on DVI
%   at the beginning of a subgroup.}
% \changes{v1.14}{1997/03/01}{Made a number of variable assignments
%   global to prevent buildup in \TeX{}'s save space.  Job
%   is not finished, but reliability has improved.}
% \changes{v1.14}{1997/03/01}{Merged a large number of changes
%  into this ".dtx" file from the "*.sty" file.}
% \changes{v1.14}{1997/03/01}{Cut superfluous documentation
%  from this file, and edited the remainder.}
% \changes{v1.15}{1997/03/08}{Fixed bug in \texttt{cal@@@print@items}
%  that suppressed entries for a single time falling at the top
%  of a selected range of times.}
% \changes{v1.16}{1997/05/19}{Minor changes to pass through language
%  options to the \texttt{dates} package.}
% \changes{v1.17}{1997/10/18}{New public release of all styles
%  and modules incorporating global bug-fixes.}
% \changes{v1.18}{1997/10/25}{Eliminated need for bogus entries
%  to protect against reads past end of file. }
% \changes{v1.19}{1997/10/26}{One more cross-nesting, of \cs{cal@offset},
%  tracked down and eliminated.}
%\iffalse
% Source tree moved under RCS
% ---------------------------
% calendar.dtx,v
% Revision 3.1.1.1  1998/01/17 18:14:52  root
% Release code, checksum verified
%
% Revision 3.1  1998/01/17 16:59:04  root
% Release code
%
% Revision 2.2  1997/11/07 10:44:05  root
% Release code.
%
% Revision 2.1.1.2  1997/11/05 12:38:40  root
% Changed RAN to rAN.
%
% Revision 2.1.1.1  1997/11/04 05:06:07  root
% Development branch
%
% Revision 2.1  1997/11/01 15:14:56  bennett
% Release code.
%
% Revision 1.10  1997/11/01 14:28:10  root
% Eliminated \enditall's from the package.
%
% Revision 1.9  1997/11/01 12:56:27  root
% Added assignment to new counter \dates@range@limit.
%
% Revision 1.8  1997/10/31 21:56:23  root
% Added hardwired \dates@requiremonthtrue immediately before
% \cal@input.
%
% Revision 1.7  1997/10/29 20:06:34  bennett
% *** empty log message ***
%
% Revision 1.6  1997/10/29 17:21:40  root
% Further change affecting subgroup breaks?
%
% Revision 1.5  1997/10/29 16:52:21  root
% Moved use of subgroup@setup to the right location (oops).
%
% Revision 1.4  1997/10/29 16:39:42  root
% Added subgroup@setup to begin@subgroup, to guard against
% starting the second and later pages of a timesheet with
% the last time from the previous page.  Thanks to Edward
% Czilli for reporting this bug.
%
% Revision 1.3  1997/10/29 13:47:57  root
% Restored date checking after discovering that it works
% correctly if files are extracted from RCS using the -kv
% option.
%
% Revision 1.2  1997/10/29 11:47:37  root
% Eliminated optional date specification from RequirePackage{dates}
%
% Revision 1.1  1997/10/29 08:17:52  root
% Initial revision
%
%\fi
%
%
% \title{Designer's Guide to the Calendar
%  package\thanks{This file is version number
%    \fileversion{}.  It was last revised on
%    \filedate.}}
%
% \author{Frank G. Bennett, Jr.}
%
%  \maketitle
%
% \DoNotIndex{\@,\@@par,\@beginparpenalty,\@empty}
% \DoNotIndex{\@flushglue,\@gobble,\@input}
% \DoNotIndex{\@makefnmark,\@makeother,\@maketitle}
% \DoNotIndex{\@namedef,\@ne,\@spaces,\@tempa}
% \DoNotIndex{\@tempb,\@tempswafalse,\@tempswatrue}
% \DoNotIndex{\@thanks,\@thefnmark,\@topnum}
% \DoNotIndex{\@@,\@elt,\@forloop,\@fortmp,\@gtempa,\@totalleftmargin}
% \DoNotIndex{\",\/,\@ifundefined,\@nil,\@verbatim,\@vobeyspaces}
% \DoNotIndex{\|,\~,\ ,\active,\advance,\aftergroup,\begingroup,\bgroup}
% \DoNotIndex{\cal,\csname,\def,\documentstyle,\dospecials,\edef}
% \DoNotIndex{\egroup}
% \DoNotIndex{\else,\endcsname,\endgroup,\endinput,\endtrivlist}
% \DoNotIndex{\expandafter,\fi,\fnsymbol,\futurelet,\gdef,\global}
% \DoNotIndex{\hbox,\hss,\if,\if@inlabel,\if@tempswa,\if@twocolumn}
% \DoNotIndex{\ifcase}
% \DoNotIndex{\ifcat,\iffalse,\ifx,\ignorespaces,\index,\input,\item}
% \DoNotIndex{\jobname,\kern,\leavevmode,\leftskip,\let,\llap,\lower}
% \DoNotIndex{\m@ne,\next,\newpage,\nobreak,\noexpand,\nonfrenchspacing}
% \DoNotIndex{\obeylines,\or,\protect,\raggedleft,\rightskip,\rm,\sc}
% \DoNotIndex{\setbox,\setcounter,\small,\space,\string,\strut}
% \DoNotIndex{\strutbox}
% \DoNotIndex{\thefootnote,\thispagestyle,\topmargin,\trivlist,\tt}
% \DoNotIndex{\twocolumn,\typeout,\vss,\vtop,\xdef,\z@}
% \DoNotIndex{\,,\@bsphack,\@esphack,\@noligs,\@vobeyspaces,\@xverbatim}
% \DoNotIndex{\catcode,\end,\escapechar,\frenchspacing,\glossary}
% \DoNotIndex{\hangindent,\hfil,\hfill,\hskip,\hspace,\ht,\it,\langle}
% \DoNotIndex{\leaders,\long,\makelabel,\marginpar,\markboth,\mathcode}
% \DoNotIndex{\mathsurround,\mbox,\newcount,\newdimen,\newskip}
% \DoNotIndex{\nopagebreak}
% \DoNotIndex{\parfillskip,\parindent,\parskip,\penalty,\raise,\rangle}
% \DoNotIndex{\section,\setlength,\TeX,\topsep,\underline,\unskip,\verb}
% \DoNotIndex{\vskip,\vspace,\widetilde,\\,\%,\@date,\@defpar}
% \DoNotIndex{\[,\{,\},\]}
% \DoNotIndex{\count@,\ifnum,\loop,\today,\uppercase,\uccode}
% \DoNotIndex{\baselineskip,\begin,\tw@}
% \DoNotIndex{\a,\b,\c,\d,\e,\f,\g,\h,\i,\j,\k,\l,\m,\n,\o,\p,\q}
% \DoNotIndex{\r,\s,\t,\u,\v,\w,\x,\y,\z,\A,\B,\C,\D,\E,\F,\G,\H}
% \DoNotIndex{\I,\J,\K,\L,\M,\N,\O,\P,\Q,\R,\S,\T,\U,\V,\W,\X,\Y,\Z}
% \DoNotIndex{\1,\2,\3,\4,\5,\6,\7,\8,\9,\0}
% \DoNotIndex{\!,\#,\$,\&,\',\(,\),\+,\.,\:,\;,\<,\=,\>,\?,\_}
% \DoNotIndex{\discretionary,\immediate,\makeatletter,\makeatother}
% \DoNotIndex{\meaning,\newenvironment,\par,\relax,\renewenvironment}
% \DoNotIndex{\repeat,\scriptsize,\selectfont,\the,\undefined}
% \DoNotIndex{\arabic,\do,\makeindex,\null,\number,\show,\write,\@ehc}
% \DoNotIndex{\@author,\@ehc,\@ifstar,\@sanitize,\@title,\everypar}
% \DoNotIndex{\if@minipage,\if@restonecol,\ifeof,\ifmmode}
% \DoNotIndex{\lccode,\newtoks,\onecolumn,\openin,\p@,\SelfDocumenting}
% \DoNotIndex{\settowidth,\@resetonecoltrue,\@resetonecolfalse,\bf}
% \DoNotIndex{\clearpage,\closein,\lowercase,\@inlabelfalse}
% \DoNotIndex{\selectfont,\mathcode,\newmathalphabet,\rmdefault}
% \DoNotIndex{\bfdefault}
% \setcounter{StandardModuleDepth}{1}
% \DeleteShortVerb{\|}
% \MakeShortVerb{\"}
%
% \begin{abstract}
% \noindent This package provides tools for creating
% customized calendars using \LaTeXe.
% \end{abstract}
%
%
% \CheckSum{1460}
%
% \section{Overview and Exhortation}
%
% Think of this package as the Music Minus One
% of the scheduling trade.  It provides a standard
% interface for drafting calendars,
% but leaves you in control of the style and
% content of the finished product.
% The calendar style generator included
% in this package can be
% used to create simple lists of events, as well
% as daily, weekly, monthly and yearly calendars in a variety of
% formats.  Calendars can be ground into DVI,
% or can be exported in an arbitrary list or table formatting
% language such as HTML, or delimited
% ASCII text.
% While the format of calendars is
% pretty much up to you, all calendars created
% using the Calendar package inherit a number of
% useful features, among which are:
% 
% \begin{itemize}
% \item Access to external lists of events
% and appointments written in a user-friendly syntax.
% \item Selective printing of long or short descriptions of
% events and appointments according to the list
% from which they originate or, in the case of appointments,
% according to their starting time.
% \item Built-in recursive entries such as "every" "monday"
% or "Every" "second" "Wednesday", governed by a range.
% \item An extensible interface within list files
% for defining calculable dates within a range
% by reference to a mathematical formula.
% \item ``Stopping'' of recursive entries by reference
% to a list of holidays.
% \item Colour-coding of lists and groups of lists
% for the readable presentation of complex schedules.
% Colours may be associated with individual lists,
% or with entire groups of lists.
% \end{itemize}
% 
% On top of this, all calendar styles have a uniform
% user interface.  For examples, please see the
% files included in the "styles" subdirectory
% in or near the filespace from which you retrieved
% this file.
% 
% Finally, the Calendar package has the virtue of
% being chilled, if not yet completely frozen.
% While there will doubtless
% be minor bug fixes and enhancements in future
% releases, this package is intended to be a finished
% and stable platform on which to build calendar
% styles.  It will not move out from underneath
% your work.  And if you draft a calendar style
% and publish it on CTAN, others will be able to
% put it straight to work on their own local lists
% of events.
% 
% ************
% The documentation to this package explains how
% to define your own calendar formats.  There are many
% possibilities, but here are a few ideas:
%
% \begin{itemize}
% \item Web maintainers
% can provide a current view of upcoming events formatted
% with a tabular calendar at the top, the dates of
% which are linked to events for that day. 
% \item Filofax
% calendars can be produced which contain institutional
% data and personal appointments on a per-user basis.
% \item  Scheduling conflicts or common free times can be identified by producing
% concordance calendars that lay the daily schedules
% of several members of staff alongside one another.
% \item Timesheets with pre-printed diary entries can be
% produced.
% \item Consolidated academic timetables can be
% produced.
% \item To simplify the maintenance of lists, a
% Web site may want to produce a forms interface
% for the distributed creation and management of lists.  This
% task is greatly simplified by the fact that the
% syntax for entries is flexible and human-readable.
% \item Users at a Web site can be given direct control over
% calendar content, by running \LaTeX{} and "dvips" from a
% CGI behind a click-box and radio-button interface.
% \end{itemize}
%
% All of these applications can be supported directly
% by the package as it stands.  All that is required
% is to define appropriate calendar formats.
% Classes and packages 
% that define new calendar formats contain only the
% essential commands which define their structure.
%
% The source of the Calendar package and related
% files is located in
% the CTAN archives under:
%
% \begin{quote}
% "macros/latex/contrib/supported/calendar"
% \end{quote}
%
% If you design a new calendar format, please upload
% it to the CTAN "/incoming" directory at "ftp.tex.ac.uk"
% and send the site maintainers a note (see the file
% "README.uploads" for their contact details) asking
% them to place it in the "styles" subdirectory
% of the Calendar package filespace.  It is best
% to send your calendar format as a "*.dtx" file, with
% documentation on how to use it (see the existing
% packages for model documentation).
% If you design a CGI or other front-end 
% that calls on a style or manages
% database entries, please send that as well, for placement
% in the "tools" subdirectory.  That way, anyone interested in
% using Calendar will find everything that is available in one
% place, and the utility of the package will be greatly
% enhanced.
%
% I do not have time at present to write a
% readable and well-presented guide to the style
% drafting process.  If you want to draft
% your own style, your best bet is to read
% through the commentary and code of an
% existing calendar style, and modify it
% to suit your needs.
% Feel free to write me
% on "fb@soas.ac.uk" if you have any questions
% or comments.
%
%\StopEventually{\PrintIndex}
%
% \section{The Macros}
%
% The Dates and Keyval packages will be used.
%
%    \begin{macrocode}
%<*style>
\DeclareOption{english}{\PassOptionsToPackage{\CurrentOption}{dates}}
\DeclareOption{german}{\PassOptionsToPackage{\CurrentOption}{dates}}
\ProcessOptions
\RequirePackage{dates}[1997/10/29]
\RequirePackage{keyval}
%    \end{macrocode}
%
% \subsection{The Calendar Formatter}
%
% \begin{macro}{\newcalendar}
% \begin{macro}{\@newcalendar}
%
% This is the business end of the package.  The
% calendar-defining front end is spread across
% two macros to allow us to use more than
% nine arguments.  The second through ninth given
% to the first macro are stored in a macro that
% is expanded in the second.
%
% (the macro defined just above newcalendar is used
% to parse the increment field)
%
%    \begin{macrocode}
\def\cal@parseincrement#1#2#{%
  \def\cal@incr{#1}%
  \def\cal@subgroup@setup{#2}}%
\long\def\newcalendar#1#2#3#4#5#6#7#8#9{%
  \expandafter\def\csname cal@#1@bridge\endcsname{%
    \def\cal@output{#2}%
    \def\cal@first@weekday{#3}%
    \def\cal@group@length{#4}%
    \def\cal@subgroup@length{#5}%
    \def\cal@item@sep@real{#6}%
    \cal@parseincrement#7{}%
    \def\cal@header{#8}%
    \def\cal@footer{#9}}%
    \@newcalendar{#1}}
%    \end{macrocode}
%
% This defines the start and finish macros for an
% environment, which will be invoked using "\begin"
% and "\end".  The head macro just expands the head
% matter, grabs its first and only argument to a
% variable for future reference, and invokes the
% "\dateread" command in order to read the date
% text entered as the content of the environment.
% The "\dateread" command will expire when it hits
% the "\end" at the bottom of the enviroment.
%
%    \begin{macrocode}
\long\def\@newcalendar#1#2#3#4#5#6#7#8#9{%
  \expandafter\def\csname#1\endcsname##1##2{%
    #4%
    \gdef\cal@optionslist{##1}%
    \setkeys{opt}{##1}%
    \gdef\cal@files{##2}%
    \dateread{}}%
%    \end{macrocode}
%
% The tail macro for the environment will start
% by setting up the starting and ending dates
% for our calendar.  Step one is to set a subrange
% start and end (which "\dateread" sets if "to" is
% used in the date text) if none is found.  The
% second step is to set the current date to be the
% start of the subrange derived from the date text,
% and generate human-readable register data for
% future reference.  We then set the overall range for
% the calendar to the subrange dates.
%
% The next step is to expand the front matter given
% in the calendar definition, after which we expand
% the material contained in the second through ninth
% arguments given to the first macro.  Then a series
% of other toggles and macros are defined.
%
% (We also set the date base, for the zigzag algorithm)
%
%    \begin{macrocode}
  \expandafter\def\csname end#1\endcsname{\relax%
    \ifnum\dates@subrange@start=0%
      \dates@subrange@start\dates@date%
      \dates@subrange@end\dates@date%
    \fi%
    \global\dates@date\dates@subrange@start%
    \caldate%
    \cal@date@base\dates@date%
    \cal@range@start\dates@subrange@start%
    \cal@range@end\dates@subrange@end%
    #5%
    \dates@range@limit\cal@range@end%
    \csname cal@#1@bridge\endcsname%
    \def\cal@groupbreak{#2}%
    \def\cal@subgroupbreak{#3}%
    \long\def\cal@entry@sep{#6}%
    \def\cal@item@init{#7}%
    \def\cal@entry@init{#8}%
    \long\def\cal@item@text{#9}%
%    \end{macrocode}
%
% We catch colors if the color package is not loaded.
%
%    \begin{macrocode}
  \@ifundefined{color}%
   {\let\textcolor\@gobble%
    \let\colorbox\@gobble}%
   {}%
%    \end{macrocode
%
%
% We then input the content of the event files given
% as the argument to the environment, if any files exist
% for processing.
%
%    \begin{macrocode}
    \ifcat$\cal@files$%
    \else%
      \dates@requiremonthtrue%
      \dates@requiredaytrue%
      \expandafter\cal@input\cal@files,,\end%
    \fi%
%    \end{macrocode}
%
% Then we sort everything.
%
%    \begin{macrocode}
    \cal@sorts%
%    \end{macrocode}
%
% We set the date to the bottom of the range again,
% and set the registers.
%
%    \begin{macrocode}
    \global\dates@date\cal@range@start%
    \caldate%
%    \end{macrocode}
%
% Finally, we produce the calendar text.
%
%    \begin{macrocode}
    \cal@top}}%
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsection{Input and Export for Event Lists}
%
% \begin{macro}{\cal@input}
% \begin{macro}{\cal@append}
% \begin{macro}{\cal@list@append}
% \begin{macro}{\cal@list@init}
% \begin{macro}{\cal@read}
%
% This is the input routine.  It starts by setting
% up to loop itself.  Then it checks to see if the
% list is empty, and sets up to quit if it is.
% If there is an item in the list, it first
% puts the remainder of the items onto the list for
% future reference.  Then the input file is defined
% to be the first item.  Then it checks to see
% if a freeze file exists.  If it does, it is input,
% and the data file is ignored.  The engine number
% counter is also incremented.  If the file does not
% exist, we check for a list file.  If one is found,
% we increment the engine counter, and turn off
% freezing --- this will be turned on in the file
% itself if a request is found there.  Then we
% just input the file for scanning.  We follow the
% text in the file with a meaningless entry as
% a buffer, and a command that shuts off the
% macro that gobbles up entries.
%
%    \begin{macrocode}
\def\cal@check@colon#1:#2#{%
  \def\dates@arg@a{#1}%
  \def\dates@arg@b{#2}}
\def\cal@input#1,#2,\end{%
  \ifcat$#1$%
    \let\cal@input@next\relax%
    \global\let\cal@files\relax%
  \else%
    \advance\cal@engine by 1%
    \cal@check@colon#1:{}%
    \ifcat$\dates@arg@b$%
      \expandafter\edef\csname cal@\the\cal@engine @color\endcsname{}%
      \xdef\cal@color{}%
    \else%
      \expandafter\dates@strip@colon\dates@arg@b%
      \expandafter\edef%
        \csname cal@\the\cal@engine @color\endcsname{\dates@arg@b}%
      \gdef\cal@color{:\dates@arg@b}%
    \fi%
    \xdef\cal@input@file{\dates@arg@a}%
    \let\cal@input@next\cal@input%
    \xdef\cal@files{#2,,\noexpand\end}%
    \IfFileExists{\cal@input@file.eve}%
      {\PackageWarning{Calendar}%
         {Using freeze file \cal@input@file.eve}%
       \expandafter\ifx\csname\cal@input@file @cal@engine\endcsname%
       \relax%
         \@@input\cal@input@file.eve\relax%
       \fi}%
      {\IfFileExists{\cal@input@file.cld}%
        {\expandafter\ifx%
           \csname\cal@input@file @cal@engine\endcsname%
         \relax%
           \cal@dofreezefalse%
           \gdef\cal@exceptionlist{}%
           \expandafter\cal@read%
           \@@input\cal@input@file.cld\relax{}%
           \ifcal@dofreeze%
             \immediate\closeout\cal@freeze@file%
           \fi%
         \fi}%
        {\@missingfileerror{\cal@input@file}{cld}}}%
  \fi%
  \expandafter\edef%
    \csname\cal@input@file @cal@engine\endcsname{\the\cal@engine}%
  \expandafter\cal@input@next\cal@files}
\def\cal@input@next@default{\expandafter\cal@input@clone\cal@files}
%    \end{macrocode}
%
% This is the handler used to put date information
% into memory and, optionally, to write data to
% a freeze file.  The chain of nested conditions
% is explained step by step.
%
%    \begin{macrocode}
\def\cal@append{%
%    \end{macrocode}
%
% \textit{If we are looking at a list of holidays, we build
% an exceptions list only.}
%
%    \begin{macrocode}
  \ifcal@holidays%
    \cal@except%
%    \end{macrocode}
%
% \textit{Otherwise we are looking at dates for use in the calendar.
% We check first for a matching exception date, and block all
% action if one is found ("\cal@checkexception" sets the condition
% that follows).}
%
%    \begin{macrocode}
  \else%
    \cal@checkexception%
    \ifcal@useentry%
%    \end{macrocode}
%
% \textit{If we are working on a range file, export to a freeze file
% is blocked.}
%
%    \begin{macrocode}
      \ifcal@noexport%
%    \end{macrocode}
%
% \textit{We only export to a freeze file if specifically requested
% to do so.  But if freezing is requested, we export all non-range
% items, regardless of the range used for the calendar.}
%
%    \begin{macrocode}
      \else%
        \ifcal@dofreeze%
          \cal@freeze%
        \fi%
      \fi%
%    \end{macrocode}
%
% \textit{The remainder of our conditions pertain to the loading of
% data into memory.  Range data is loaded, but only once,
% so we use a separate condition to block action here.}
%
%    \begin{macrocode}
      \ifcal@noload%
      \else%
%    \end{macrocode}
%
% \textit{If the current date is outside the range for
% Memory store is only performed
% for items within our overall date range for this
% calendar.  Having this data in memory
% would do no affirmative harm, but it is dead weight
% since we'll not be using it.}
%
%    \begin{macrocode}
        \ifnum\dates@date<\cal@range@start%
        \else%
          \ifnum\dates@date>\cal@range@end%
          \else%
            \cal@list@init{events}%
            \cal@list@init{appointments}\relax%
%    \end{macrocode}
%
% \textit{We build separate lists for events and appointments.}
%
%    \begin{macrocode}
            \ifnum\dates@time@start=0%
              \cal@list@append{events}%
            \else%
              \cal@list@append{appointments}%
            \fi%
          \fi%
        \fi%
      \fi%
    \fi%
  \fi}
%    \end{macrocode}
%
% This appends to the selected list type for the
% current date.  It grabs the list content, if any,
% to a register.  Then it defines the list to be
% itself plus the new set of details.
%
%    \begin{macrocode}
\def\cal@list@append#1{%
  \cal@reg@a=%
    \expandafter\expandafter\expandafter{%
    \csname\the\dates@date @#1\endcsname}%
  \cal@reg@b\expandafter{\theshorttext}%
  \cal@reg@c\expandafter{\thelongtext}%
  \expandafter\edef%
  \csname\the\dates@date @#1\endcsname{%
    \the\cal@reg@a%
    \noexpand\cal@delim%
    {\the\dates@time@start}%
    {\the\dates@time@end}%
%    \end{macrocode}
%
% The no-export toggle is set whenever the ends of a range are being
% loaded.  We use that here to fiddle the engine number for
% these entries.  This is necessary to prevent color from being
% applied to them.
%
%    \begin{macrocode}
    {\ifcal@noexport%
       0%
     \else%
       \the\cal@engine%
     \fi}%
    {\the\cal@reg@b}%
    {\the\cal@reg@c}}}%
%    \end{macrocode}
%
% This is the list initializer.  We first
% check to see if there is an existing
% list, and initialize it if it is new.
%
%    \begin{macrocode}
\def\cal@list@init#1{%
  \expandafter\ifx%
  \csname\the\dates@date @#1\endcsname%
  \relax%
    \expandafter\def%
    \csname\the\dates@date @#1\endcsname%
      {}%
  \fi}
%    \end{macrocode}
%
% This is the file scanner.  The input handler
% can be redefined.  The default at start-up is
% to handle list files by putting them into memory.
%
%    \begin{macrocode}
\def\cal@read{%
  \dateread{\cal@append}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Sorting Routines}
%
% \begin{macro}{\cal@sorts}
% \begin{macro}{\cal@@sorts}
% \begin{macro}{\cal@@sorts@exit}
% \begin{macro}{\cal@@sort@init}
%
% This is the front end for sorting all items in
% memory.  We step through the range day by day,
% and execute the sort routine on any lists that
% are found.  One could avoid processing the empty
% days by loading all items into a single list, but
% a linear sort on a large number of items can be
% very slow, both because the work done in a linear
% sort grows geometrically, and because the sorting
% alogorithm requires more comparisons.
% On balance, this is a faster approach
% in most cases.
%
% We start by setting the date to be the start of
% the range, and do a "\let" that will set up
% recursion in the next macro in the chain.  We then
% execute that macro.
%
%    \begin{macrocode}
\def\cal@sorts{%
  \global\dates@date\cal@range@start%
  \let\cal@@sorts@next\cal@@sorts%
  \cal@@sorts}
%    \end{macrocode}
%
% The following will die when we hit the end of the range.
% Otherwise, it will look to see if there is something
% in a list for the current date in the events or appointment
% macros, and execute a sort of each if required.
%
%    \begin{macrocode}
\def\cal@@sorts{\relax%
  \ifnum\dates@date>\cal@range@end%
    \let\cal@@sorts@next\cal@@sorts@exit%
  \else%
    \expandafter\ifx%
    \csname\the\dates@date @events\endcsname\relax%
    \else%
      \cal@sort{\the\dates@date @events}%
    \fi%
    \expandafter\ifx%
    \csname\the\dates@date @appointments\endcsname\relax%
    \else%
      \cal@sort{\the\dates@date @appointments}%
    \fi%
    \global\advance\dates@date by 1%
  \fi%
  \cal@@sorts@next}
%    \end{macrocode}
%
% When we finish all of the sorting work, we restore the date
% to the start of the range, and we're ready to make a calendar!
%
%    \begin{macrocode}
\def\cal@@sorts@exit{%
  \global\dates@date\cal@range@start%
  \caldate}
%    \end{macrocode}
%
% This is used to initialize a list for sorting.  It
% simply appends an entry with a time of minus one
% to the end of the primary working list.
%
%    \begin{macrocode}
\def\cal@sort@init{%
  \cal@sort@A=-1%
  \cal@sort@B=0%
  \cal@sort@C=0%
  \cal@sort@D{}%
  \cal@sort@E{}%
  \global\let\cal@sort@new\cal@sort@list%
  \cal@appendright%
  \let\cal@sort@list\cal@sort@new%
  \gdef\cal@sort@new{}%
  \cal@sort@passonetrue}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\cal@sort}
% \begin{macro}{\cal@@sort}
% \begin{macro}{\cal@appendright}
% \begin{macro}{\cal@sort@swap}
%
% This is the front end for sorting individual lists
% of items.  It takes a single
% list macro name as its argument, invokes sorting on that
% list macro, and sets it to be the sorted form.  The sorting
% setup here is designed to be easy to follow.  It is probably
% not the most efficient way of sorting, but the size of lists
% is small (probably about ten items at the upper end),
% so speed is not really an issue.
%
% The name of the list is given as text, to keep the code
% where this is invoked more easily readable.
%
%    \begin{macrocode}
\def\cal@sort#1{%
  \expandafter\let\expandafter\cal@sort@list\csname#1\endcsname%
  \cal@sort@init%
  \global\let\cal@delim\cal@@sort%
  \cal@sort@list%
  \expandafter\let\csname#1\endcsname\cal@sort@new}
%    \end{macrocode}
% This is the sort engine itself.  Our data in memory consists of
% a list macro in groups of five items each.  We will
% use this list under the name of "\cal@sort@list", and a working
% sort list for export under the name of "\cal@sort@new".
%
% We begin
% by grabbing the items to registers.
%
%    \begin{macrocode}
\def\cal@@sort#1#2#3#4#5{%
  \cal@sort@a=#1%
  \cal@sort@b=#2%
  \cal@sort@c=#3%
  \cal@sort@d{#4}%
  \cal@sort@e{#5}%
%    \end{macrocode}
%
% Our default action is to do nothing when we finish
% with each sorting comparison; processing will be passed
% to the next delimited item in the list.
%
%    \begin{macrocode}
  \let\cal@@sort@next\relax%
%    \end{macrocode}
%
% Every list for sorting is assumed to end in an entry with a
% time of minus one.  When this is encountered, we export
% the last held item, and just expire if there was no change
% in the list.
%
% set the new list to be "\cal@sort@list", or we perform
% some actions to prepare for rerunning the list.
%
%    \begin{macrocode}
  \ifnum\cal@sort@a=-1\relax%
    \message{.}%
%    \cal@sort@swap%  ... ?
    \cal@appendright%
    \ifcal@nosortchange%
%    \end{macrocode}
%
% If we are to rerun the list, we reset the change toggle
% and the pass toggle.  Then we export the held item,
% swap, and export the existing end-of-list marker.
% Then we set next to be the new list, and blank the
% new list to prevent geometric progression.
%
%    \begin{macrocode}
    \else%
      \cal@nosortchangetrue%
      \cal@sort@passonetrue%
%      \cal@appendright%
      \cal@sort@swap%
      \cal@appendright%
      \let\cal@@sort@next\cal@sort@new%
      \gdef\cal@sort@new{}%
    \fi%
%    \end{macrocode}
%
% If are not at the end of the list, we start here.
% If this is the first pass, we do nothing.  Otherwise
% we perform a series of comparisons.
%
%    \begin{macrocode}
  \else%
    \ifcal@sort@passone%
    \else%
%    \end{macrocode}
%
% The time held is larger than the existing time.
% We need to change the order of the list, so we say so.
% We swap and export the smaller item.
%
%    \begin{macrocode}
    \ifnum\cal@sort@A>\cal@sort@a\relax%
      \cal@nosortchangefalse%
      \cal@sort@swap%
      \cal@appendright%
%    \end{macrocode}
%
% The time held is less than or equal to the existing time.\footnote{We also
% need to keep engine numbers in sequence.  But the
% engine held must be less than the existing engine
% because they are loaded in sequence.  We therefore
% do not need to check the next level.}
% \changes{1996/12/25}{v1.2}{Cut out a check for equal
%  values in the sort comparison, and eliminated an erroneous
%  swap action.}
%
%    \begin{macrocode}
    \else%
%      \ifnum\cal@sort@A=\cal@sort@a\relax%
        \cal@appendright%
%    \begin{macrocode}
%
% The time held was less than the existing time.
%
%    \begin{macrocode}
%      \else%
%        \cal@appendright%
%      \fi%
    \fi%
  \fi%
%    \end{macrocode}
%
% Swap registers.  The current small registers were not exported
% to the new list, and are used as the large registers in the
% next pass.
%
%    \begin{macrocode}
  \cal@sort@swap%
  \cal@sort@passonefalse%
  \fi%
  \cal@@sort@next}
%    \end{macrocode}
%
% This simply appends to the end of the export list.
%
%    \begin{macrocode}
\def\cal@appendright{%
  \cal@reg@a\expandafter{\cal@sort@new}%
  \xdef\cal@sort@new{%
    \the\cal@reg@a%
    \noexpand\cal@delim%
    {\the\cal@sort@A}%
    {\the\cal@sort@B}%
    {\the\cal@sort@C}%
    {\the\cal@sort@D}%
    {\the\cal@sort@E}}}
%    \end{macrocode}
%
% This swaps the large and small registers (trust me).
%
%    \begin{macrocode}
\def\cal@sort@swap{%
  \cal@count@a\cal@sort@a%
  \cal@sort@a\cal@sort@A%
  \cal@sort@A\cal@count@a%
  \cal@count@a\cal@sort@b%
  \cal@sort@b\cal@sort@B%
  \cal@sort@B\cal@count@a%
  \cal@count@a\cal@sort@c%
  \cal@sort@c\cal@sort@C%
  \cal@sort@C\cal@count@a%
  \cal@reg@a\expandafter{\the\cal@sort@d}%
  \cal@sort@d\expandafter{\the\cal@sort@D}%
  \cal@sort@D\expandafter{\the\cal@reg@a}%
  \cal@reg@a\expandafter{\the\cal@sort@e}%
  \cal@sort@e\expandafter{\the\cal@sort@E}%
  \cal@sort@E\expandafter{\the\cal@reg@a}}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{The Calendar Generator}
%
% The following is run at the start of table generation only.
% After adjusting the global range for the table,
% it sets up the limiting counters for lines and groups.
% It also sets up a counter that tracks the number of items
% in a line and another that tracks the number of items
% in a group,
% and sets counters indicating the day on which
% each line will start and finish.  It then outputs the
% headers and chains to the first macro in the loop.
%
%    \begin{macrocode}
\def\cal@top{\relax%
  \ifnum\tracingdates>0%
    \message{^^J\themonth}%
  \fi%
  \let\cal@add@date@item\cal@add@date@item@default%
  \advance\cal@range@end by 1%
  \global\cal@subgroup@count0%
  \global\cal@group@count0%
  \cal@subgroup@len\cal@subgroup@length%
  \advance\cal@subgroup@len by -1\relax%
  \global\cal@group@len\cal@group@length%
%  \advance\cal@group@len by -1\relax%
  \cal@first@weekd\cal@first@weekday\relax%
  \ifnum\cal@first@weekd=0%
    \cal@last@weekd=6%
  \else%
    \cal@last@weekd\cal@first@weekd%
    \advance\cal@last@weekd by -1%
  \fi%
  \cal@subgroup@setup%
  \cal@output{\cal@header}\cal@begin@subgroup}
%    \end{macrocode}
%
% The following begins every line in the table.  
% It zeros the line item counter, then
% checks to see if we are ready to finish the table.
% If we are not finished, it checks to see if we have
% finished a group.  If so, it puts the name of the new month
% on the terminal, resets the line and group counters,
% and grabs the group length afresh (this can change if,
% say, the group is a month).  It then puts down a subfooter
% (left out in the routine that feeds into this, so that
% nothing will intervene between it and the foot), a footer
% and a new header.  It then either pads or goes straight
% to input, as appropriate.
% If we are not at the end of a group, it puts down the start of a line.
% It then either starts the padding routine or goes straight
% to the item insertion routine.  
% If we were ready to finish,
% it puts down a final line ending and footer, then dies.
%
%    \begin{macrocode}
\def\cal@begin@subgroup{%
  \global\cal@subgroup@count=0%
  \global\def\cal@item@sep{}%
  \ifnum\dates@date<\cal@range@end\relax%
    \ifnum\cal@group@count=\cal@group@len\relax%
      \ifnum\tracingdates>0%
        \message{^^J\themonth}%
      \fi%
      \global\cal@group@count=0%
      \global\cal@group@len\cal@group@length%
      \cal@subgroup@setup%
      \cal@output{\cal@groupbreak}\relax%
      \ifnum\cal@first@weekd<7%
        \let\next\cal@pad@start%
      \else%
        \let\next\cal@add@date@item%
      \fi%
    \else%
      \ifnum\cal@first@weekd<7\relax%
        \let\next\cal@pad@start%
      \else%
        \let\next\cal@add@date@item%
      \fi%
    \fi%
  \else%
    \cal@output{\cal@footer}%
    \let\next\relax%
  \fi%
  \next}
%    \end{macrocode}
%
% This adds a date item. It starts by checking to 
% see if we are at the end of a group.  It then either
% selects padding or a new line, as requested.
% If this is not the end of a group, we check to see
% if it is the end of a line.  If so, it puts out a
% subfooter, but only if we're not going to be finishing
% the whole table.  (The same treatment should be given
% to groups, come to think of it --- so there's at least
% one known bug here).  If we're not at the end of a line,
% we place the item separator (which might be asleep),
% then let it wake up.  This is followed by the item
% text and updates to the date and counters.
%
%    \begin{macrocode}
\def\cal@add@date@item@default{\relax%
  \ifnum\cal@group@count=\cal@group@len\relax%
    \ifnum\cal@first@weekd<7%
      \let\next\cal@pad@end%
    \else%
      \let\next\cal@begin@subgroup%
    \fi%
    \if\cal@incr G%
      \global\advance\dates@date by 1%
      \caldate%
    \fi%
    \if\cal@incr z%
      \global\advance\dates@date by1%
    \fi%
  \else\relax%
    \ifnum\cal@subgroup@count>\cal@subgroup@len\relax%
      \if\cal@incr z%
        \global\dates@date\cal@date@base%
%        \global\advance\dates@date by-1%
      \fi%
      \ifnum\dates@date<\cal@range@end%
        \if\cal@incr S%
          \global\advance\dates@date by1%
          \caldate%
        \fi%
        \cal@subgroup@setup%
        \cal@output{\cal@subgroupbreak}%
      \fi%
      \let\next\cal@begin@subgroup%
    \else%
      \cal@output{\cal@item@sep}%
      \global\def\cal@item@sep{\cal@item@sep@real}\relax%
      \ifnum\tracingdates>0%
        \message{\theday}%
      \fi%
      \cal@item@init%
      \cal@output{\cal@item@text}%
      \if\cal@incr I%
        \global\advance\dates@date by 1%
        \caldate%
      \fi%
      \if\cal@incr z%
        \global\advance\dates@date by 1%
        \caldate%
      \fi%
      \global\advance\cal@subgroup@count by 1\relax%
      \global\advance\cal@group@count by 1\relax%
      \let\next\cal@add@date@item%
    \fi%
  \fi%
  \next}
%    \end{macrocode}
%
% This pads out a line if the current date is later
% than the day that should start a table.
%
% It then calculates an offset that will be used
% by the padding loop, restoring the current date
% after the figure has been determined.
%
%    \begin{macrocode}
\def\cal@pad@start{%
  \cal@temp@count\dates@date%
  \bgroup%
    \global\cal@offset=\dates@date%
    \prevday\cal@first@weekd%
    \global\advance\cal@offset by -\dates@date%
  \egroup%
  \global\dates@date\cal@temp@count%
  \cal@pad@@start}
%    \end{macrocode}
%
% This is the padding loop.  It moves to the beginning of
% the next line
% if padding is unnecessary or has been completed,
% putting the item separator to sleep as it does so.
% Otherwise, it wakes up the separator,
% puts it down, and increments
% the group and line counters.
%
%    \begin{macrocode}
\def\cal@pad@@start{\relax%
  \ifnum\cal@offset=0\relax%
    \global\def\cal@item@sep{}%
    \let\next\cal@add@date@item%
  \else%
    \global\def\cal@item@sep{\cal@item@sep@real}%
    \cal@output{\cal@item@sep}%
    \global\advance\cal@offset by -1\relax%
    \global\advance\cal@subgroup@count by 1\relax%
    \let\next\cal@pad@@start%
  \fi%
  \next}
%    \end{macrocode}
%
% This pads a line to the ending day of the week.
% It calculates the offset,
% being careful not to let it hit an absurd value.
%
%    \begin{macrocode}
\def\cal@pad@end{%
  \cal@temp@count\dates@date%
  \bgroup%
    \global\cal@offset=\dates@date\relax%
    \nextday\cal@last@weekd%
    \advance\dates@date by -\cal@offset%
    \global\cal@offset\dates@date\relax%
    \ifnum\cal@offset=6%
      \global\cal@offset=0%
    \else%
      \global\advance\cal@offset by 1%
    \fi%
  \egroup%
  \global\dates@date\cal@temp@count%
  \cal@pad@@end}
%    \end{macrocode}
%
% If the offset is zero, there is no (longer) need for
% padding, and we go back to see if it's okay to start
% another line.  Otherwise we output an item separator
% and iterate.
%
%    \begin{macrocode}
\def\cal@pad@@end{\relax%
  \ifnum\cal@offset=0\relax%
    \let\next\cal@begin@subgroup%
  \else%
    \cal@output{\cal@item@sep}%
    \global\advance\cal@offset by -1%
    \global\advance\cal@subgroup@count by 1\relax%
    \let\next\cal@pad@@end%
  \fi%
  \next}
%    \end{macrocode}
%
% \subsection{Event Macros}
%
% The macros in this section are used to place text in the
% finished calendar.  They are used by designers with
% the "\newcalendar" formatting macro.
%
%
% We provide several macros for conditional execution
% of text and color.  The first two make rough decisions
% about an entire list of items, and are intended for
% use in tiny calendars in which specific text relating
% to events is not included.
%
% \begin{macro}{\ifanyitem}
%
% This executes one of two arguments depending on whether
% there is an event or appointment associated with the
% current date.  We'll use this for small calendars
% on black and white printers, to boldface text
% showing that there is something significant about
% the date.
%
%    \begin{macrocode}
\def\ifanyitem#1#2{%
  \gdef\cal@temp{#1}%
  \expandafter\ifx%
  \csname\the\dates@date @events\endcsname%
  \relax%
    \expandafter\ifx%
    \csname\the\dates@date @appointments\endcsname%
    \relax%
      \gdef\cal@temp{#2}%
    \fi%
  \fi%
  \let\next\cal@temp%
  \next}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\getanycolor}
% \begin{macro}{\get@calcolor}
% \begin{macro}{\calcolor}
%
% The next extracts a colour
% associated with a date.  The color is returned in
% "\calcolor".
%
%    \begin{macrocode}
\def\getanycolor{%
  \gdef\calcolor{}%
  \global\let\cal@delim\get@anycolor%
  \csname\the\dates@date @events\endcsname%
  \csname\the\dates@date @appointments\endcsname}
%    \end{macrocode}
%
% The following is executed on each item in the list.
% When a color is found, we stick with that; the
% order of lists fed to the calendar will determine
% priority.
% \changes{v0.12}{1996/12/21}{First attempt at color
%  coding --- it works!}
%
%    \begin{macrocode}
\def\get@anycolor#1#2#3#4#5{%
  \ifcat$\calcolor$%
    \expandafter\ifx%
    \csname cal@#3@color\endcsname%
    \relax%
    \else%
      \xdef\calcolor{\csname cal@#3@color\endcsname}%
    \fi%
  \fi}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% Next, we have macros for working with lists.  The set here
% sets up for the execution of a list, and dumps the list into the
% DVI hopper.  Any list found will formatted using
% "\thecaltext", which the user may wish to redefine.
%
% If options are given to the command, only matching
% entries will be printed.
%
% We permit the selection of
% appointments and events by time, and
% by engine number.\footnote{The latter feature will allow
% the creation of concordance calendars that lay
% schedules side by side on the page.  It should be
% possible, with minor enhancements to the Calendar
% package itself, to produce a schedule concordance
% that formats itself to the number of top-level lists
% fed to it.  Really terrific if you have a use for it\ldots}
%
% We begin by hunting for options.
%
%    \begin{macrocode}
\def\cal@get@events{%
  \def\theevents{}%
  \gdef\cal@entry@macro{\theevents}%
  \expandafter\let%
  \expandafter\cal@dumplist\csname\the\dates@date @events\endcsname%
  \cal@print@items}
\def\cal@get@appointments{%
  \gdef\theappointments{}%
  \gdef\cal@entry@macro{\theappointments}%
  \expandafter\let%
  \expandafter\cal@dumplist%
  \csname\the\dates@date @appointments\endcsname%
  \cal@print@items}
\def\cal@print@items{%
  \cal@sort@passonetrue%
  \@ifnextchar[%
   {\cal@@print@items}%
   {\cal@@print@items[-1/-1]}}
\def\cal@@print@items#1[#2/#3]{%
  \cal@select@start=#2%
  \cal@select@end=#3%
  \@ifnextchar[%
   {\cal@@@print@items}%
   {\cal@@@print@items[-1]}}
\def\cal@@@print@items#1[#2]{%
  \cal@engine@limit=#2%
  \global\let\cal@delim\cal@print@format%
  \cal@dumplist}
%    \end{macrocode}
%
% I'm sure there is a more clever way to do this,
% but I can't think of it tonight.  If no value
% is given for an option, it becomes irrelevant
% to the decision of whether or not to print.  Otherwise,
% a match for its value is required.
%
%    \begin{macrocode}
\def\cal@print@format#1#2#3#4#5{\relax%
  \ifcat$#4$%
  \else%
    \def\theshorttext{#4}%
    \ifcat$#5$%
      \let\thelongtext\theshorttext%
    \else%
      \def\thelongtext{#5}%
    \fi%
    \global\dates@time@start#1\relax%
    \global\dates@time@end#2\relax%
    \mod{60}\dates@time@start\cal@minutes@start%
    \cal@hours@start\dates@three%
    \divide\cal@hours@start by60%
    \mod{60}\dates@time@end\cal@minutes@end%
    \cal@hours@end\dates@three%
    \divide\cal@hours@end by60%
    \ifnum\cal@minutes@start<10%
      \xdef\cal@minutes@start@mac{%
        0\the\cal@minutes@start}%
    \else%
      \xdef\cal@minutes@start@mac{%
        \the\cal@minutes@start}%
    \fi%
    \ifnum\cal@minutes@end<10%
      \xdef\cal@minutes@end@mac{%
        0\the\cal@minutes@end}%
    \else%
      \xdef\cal@minutes@end@mac{%
        \the\cal@minutes@end}%
    \fi%
    \xdef\cal@appt@start@text{%
      \the\cal@hours@start:\cal@minutes@start@mac}%
    \xdef\cal@appt@end@text{%
      \the\cal@hours@end:\cal@minutes@end@mac}%
    \cal@doeventfalse%
    \cal@doapptfalse\relax%
    \ifnum\cal@engine@limit>-1\relax%
      \ifnum#3=\cal@engine@limit%
        \cal@doeventtrue%
      \fi%
    \else%
        \cal@doeventtrue%
    \fi\relax%
    \ifnum\cal@select@start>-1\relax%
%
% We eliminate anything that is outside or just
% touches the time slot we're dealing with.
%
      \ifnum\dates@time@start<\cal@select@end%
        \ifnum\dates@time@end>\cal@select@start%
          \cal@doappttrue%
%
% Ha! But just-touching entries that are pinpoint
% times are okay.
%
        \else
          \ifnum\dates@time@end=\cal@select@start%
            \ifnum\dates@time@start=\dates@time@end%
              \cal@doappttrue%
            \fi%
          \fi%
        \fi%
      \fi%
    \else%
      \cal@doappttrue%
    \fi%
    \ifcal@doappt%
      \ifcal@doevent%
        \xdef\calcolor{\csname cal@#3@color\endcsname}%
        \ifcal@sort@passone%
          \cal@reg@a{}%
        \else%
          \cal@reg@a\expandafter{\cal@entry@sep}%
        \fi%
        \cal@times@init%
        \global\let\cal@textcolor\relax%
        \cal@entry@init%
        \global%
        \global\let\cal@textcolor\cal@textcolor@default%
        \cal@reg@b\expandafter{\cal@entry@text}%
        \cal@reg@c%
         \expandafter\expandafter%
         \expandafter{\cal@entry@macro}%
        \expandafter\xdef\cal@entry@macro{%
           \the\cal@reg@c%
           \the\cal@reg@a%
           \the\cal@reg@b}%
        \cal@sort@passonefalse%
      \fi%
    \fi%
  \fi}
%    \end{macrocode}
%
% This macro is used to initialize the values of
% text-literal macros "\thetimestart" and "\thetimeend".
%
%    \begin{macrocode}
\def\cal@times@init{%
  \mod{60}\dates@time@start\dates@one%
  \dates@three\dates@time@start%
  \divide\dates@three by 60%
  \ifnum\dates@one<10\relax%
    \xdef\cal@temp{0\the\dates@one}%
  \else%
    \xdef\cal@temp{\the\dates@one}%
  \fi%
  \xdef\thetimestart{\the\dates@three:\cal@temp}%
  \mod{60}\dates@time@end\dates@one%
  \dates@three\dates@time@end%
  \divide\dates@three by 60%
  \ifnum\dates@one<10\relax%
    \xdef\cal@temp{0\the\dates@one}%
  \else%
    \xdef\cal@temp{\the\dates@one}%
  \fi%
  \xdef\thetimeend{\the\dates@three:\cal@temp}}
%    \end{macrocode}
%
% And last but not least, we have the default macros used
% to print the text.  Users may want to season this one
% to taste, but it should serve for most purposes.
% We need to define two macros.  One always goes to DVI,
% and can contain non-printable stuff.  The other goes
% may be routed to an external file, and should only
% contain things that expand to text, as nearly as possible.
%
%    \begin{macrocode}
\def\cal@textcolor@default#1#2{%
  \@ifundefined{color}
    {\ifcat$#1$#2\else\textbf{#2}\fi}
    {\ifcat$#1$#2\else\textcolor{#1}{#2}\fi}}
\global\let\cal@textcolor\cal@textcolor@default
%    \end{macrocode}
%
% \subsection{Parser Customizations}
%
% This section contains macros that are used to alter
% the behaviour of the "\dateread" macro.  Two new commands
% are introduced, "freeze" and "range".  The first sets a toggle
% that will cause pre-processed dates to be exported to
% a freeze file for the list being imported.  The second
% sets a range for the current import file by referring to
% a separate import file containing the range information.
%
% \begin{macro}{\fremac}
% \begin{macro}{\cal@freeze}
% \begin{macro}{\event}
%
% The first set is pretty simple.  Users must be cautioned, however,
% that they should only use this macro at the \textit{top} of a
% file to be frozen, in order to catch all of the data it contains.
% A patch could probably be applied to kill the parser if
% "\fremac" occurs after the first argument is read.  Later, later!
%
%    \begin{macrocode}
\def\fremac{%
  \immediate\openout\cal@freeze@file=\cal@input@file.eve\relax
  \cal@dofreezetrue%
}
%    \end{macrocode}
%
% The following macro is used to export text if the
% "\cal@dofreeze" toggle is on.
%
%    \begin{macrocode}
{\catcode`\%=12\xdef\cal@percent{%}}
\def\cal@freeze{%
  \immediate\write\cal@freeze@file\relax%
  {\string\event%
    {\the\dates@date}%
    {\the\dates@time@start}%
    {\the\dates@time@end}%
    {\theshorttext}%
    {\thelongtext}\cal@percent}}
%    \end{macrocode}
%
%
% Frozen export files contain "\event" macros, the arguments to
% which contain frozen data.  The "\event" macro loads date items
% into memory via the same handler used to import fresh-cooked
% data.  We don't set the engine number from the file, because
% we've already set the figure for this run.
%
%    \begin{macrocode}
\def\event#1#2#3#4#5{%
  \global\dates@date=#1\relax%
  \global\dates@time@start=#2\relax%
  \global\dates@time@end=#3\relax%
  \def\theshorttext{#4}%
  \def\thelongtext{#5}%
  \cal@append}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\ranmac}
% \begin{macro}{\cal@@@read@ranmac}
% \begin{macro}{\cal@get@range}
% \begin{macro}{\cal@get@@range}
% \begin{macro}{\rANmac}
%
% This set of macros fetches a file containing
% ranges (or other dates, although that would not
% be wise) into the current file.
% We need to snatch the word immediately following the
% command.  We do this by diverting the flow of the
% date parsing routines, as documented in the Dates
% package.
%
%    \begin{macrocode}
\def\ranmac{%
  \global\let\dates@@@read\cal@@@read@ranmac}%
%    \end{macrocode}
%
% The following will grab the very next word after
% "range", and input that file immediately, so that
% the currently-running dates parser can pass over
% it.  We look forward for a brace; if we
% find one, it means that the user put a braced
% argument after the range as a comment.  
%
%    \begin{macrocode}
\def\cal@@@read@ranmac{%
  \global\let\dates@@@read\dates@@@read@default%
  \@ifoverword\dates@serious@brace%
    {\expandafter\cal@get@range\@gobble}%
    {\cal@get@range}%
    {\message{This can't happen.}}}
%    \end{macrocode}
%
% The following two macros grab the range into the
% current parsing process.  The name of the file
% is expanded first, then the "\@@input" is expanded,
% then the parser proceeds without knowing that
% the text it sees came from elsewhere.
%
%    \begin{macrocode}
\def\cal@get@range{%
  \cal@noexporttrue%
  \expandafter\ifx%
  \csname\@overword @range@loaded\endcsname%
  \relax%
    \expandafter\def%
    \csname\@overword @range@loaded\endcsname{%
      1}%
  \else%
    \cal@noloadtrue%
  \fi%
  \IfFileExists{\@overword.cld}%
    {\expandafter\cal@get@@range\@overword.cld rAN }%
    {\@missingfileerror{\@overword}{cld}}}
%    \end{macrocode}
%
% We need a single macro that grabs stuff.
%
%    \begin{macrocode}
\def\cal@get@@range{%
  \expandafter\dates@read\@@input}
%    \end{macrocode}
%
% We need to prevent the range data from being
% loaded into memory multiple times.  We also
% never want to export this data to a freeze
% file; there would be no tidy means of determining
% which range data had been loaded and which
% not.
%
% We accomplish these effects
% by checking whether this range has been
% loaded previously, and toggling
% "\ifcal@noload" to true in the above
% macro if it has.  We also toggle "\ifcal@noexport"
% to true.  We then plant
% a macro after the imported text that will
% restore this functionality in "\cal@append".
% An all-caps word
% in the user text will be lower-cased, so this
% will not cause confusion.
%
% In a future release, the entry of ranges directly
% into a list file should probably be prevented;
% freezing several lists containing a literal range
% would introduce precisely the problem referred to
% in the first paragraph of this comment.
%
% The reset for "\cal@holidays" supports the modified
% behaviour required by the holiday option immediately
% below.
%
%    \begin{macrocode}
\def\rANmac{%
  \cal@holidaysfalse%
  \cal@noloadfalse\cal@noexportfalse}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\holmac}
% \begin{macro}{\cal@except}
% \begin{macro}{\cal@checkexception}
% \begin{macro}{\cal@@checkexception}
%
% Some lists should ignore entries that fall on a holiday.
% This is a property of the list, and so is governed by
% a list of holidays called at the top of the list itself;
% the user writing a calendar document does not need or
% want control over holidays.
%
% We accomplish this by importing a holidays list into the
% document, using the routines above.  However, we
% modify the action for the parser so that it builds an
% exceptions list.  This action is built into the
% "\cal@append" macro.
%
%    \begin{macrocode}
\def\holmac{%
  \cal@holidaystrue%
    \global\let\dates@@@read\cal@@@read@ranmac}%
%    \end{macrocode}
%
% The "\cal@append" macro will call the following macro
% to build an exceptions list.
%
%    \begin{macrocode}
\def\cal@except{%
  \cal@reg@a\expandafter{\cal@exceptionlist}%
  \xdef\cal@exceptionlist{%
    \noexpand\cal@delim{\the\dates@date}\the\cal@reg@a}}
%    \end{macrocode}
%
% This sets to false if an entry exists on the exception list,
% otherwise true.
%
%    \begin{macrocode}
\def\cal@checkexception{%
  \cal@useentrytrue%
  \global\let\cal@delim\cal@@checkexception%
  \cal@exceptionlist}
%    \end{macrocode}
%
% This sets the condition, via the above macro, by checking each
% item in the list.
%
%    \begin{macrocode}
\def\cal@@checkexception#1{\relax%
  \ifnum\dates@date=#1\relax\cal@useentryfalse\fi}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\lismac}
%
% We allow nested lists.  We avoid nested input by placing the
% name of the file onto the input list, so that the input
% routine will pick it up during tail recursion.  Nonetheless
% we want the colors of susidiary lists to be governed by
% the color at the top level, so we put the last-defined color onto the
% list as well.
%
%    \begin{macrocode}
\def\lismac{%
  \global\let\dates@@@read\cal@pass@list}
%    \end{macrocode}
%
% We need a little gadget to safely extract the contents of the
% file list.
%
%    \begin{macrocode}
\def\cal@grablist#1\end{%
  \def\cal@grabbedlist{#1}}
%    \end{macrocode}
%
% This just does the passing and returns control to "\dates@@@read".
%
%    \begin{macrocode}
\def\cal@pass@list{%
  \expandafter\cal@grablist\cal@files%
  \global\let\dates@@@read\dates@@@read@default%
  \@ifoverword\dates@serious@brace%
    {\xdef\cal@files{%
       \@overword\cal@color,\cal@grabbedlist\noexpand\end}%
     \expandafter\dates@read\@gobble}%
    {\message{I don't think I'm supposed to do this}%
     \xdef\cal@files{%
       \@overword\cal@color,\cal@grabbedlist\noexpand\end}}%
    {\message{This can't happen}}}
%    \end{macrocode}
%\end{macro}
%
% \subsection{Initializations}
%
% Before any of this runs, we need the following registers,
% macros and conditionals.
%
%    \begin{macrocode}
\newcount\cal@first@weekd
\newcount\cal@range@start
\newcount\cal@range@end
\newcount\cal@temp@count
\newcount\cal@last@weekd
\newcount\cal@subgroup@len
\newcount\cal@offset
\newcount\cal@subgroup@count
\newcount\cal@group@count
\newcount\cal@group@len
\newcount\cal@engine
\newcount\cal@engine@limit
\newcount\cal@select@start
\newcount\cal@select@end
\newcount\cal@hours@start
\newcount\cal@minutes@start
\newcount\cal@hours@end
\newcount\cal@minutes@end
\newcount\tracingdates
\tracingdates=1
\def\cal@sort@new{}
\newtoks\cal@reg@a
\newtoks\cal@reg@b
\newtoks\cal@reg@c
\newcount\cal@sort@A
\newcount\cal@sort@B
\newcount\cal@sort@C
\newtoks\cal@sort@D
\newtoks\cal@sort@E
\newcount\cal@sort@a
\newcount\cal@sort@b
\newcount\cal@sort@c
\newtoks\cal@sort@d
\newtoks\cal@sort@e
\newcount\cal@count@a
\newwrite\cal@freeze@file
\newif\ifcal@sort@passone
\newif\ifcal@nosortchange
\newif\ifcal@dofreeze
\newif\ifcal@noload
\newif\ifcal@noexport
\newif\ifcal@holidays
\newif\ifcal@useentry
\newif\ifcal@doevent
\newif\ifcal@doappt
\def\cal@insert#1{#1}
\expandafter\edef\csname cal@0@color\endcsname{black}
\def\theappointments{}
\def\theevents{}
\def\cal@exceptionlist{}
\newcount\cal@date@base
%</style>
%    \end{macrocode}
%
%\iffalse
% \section{The Installation File}
%    \begin{macrocode}
%<*installer>
\def\batchfile{calendar.ins}
\input docstrip.tex

\keepsilent

\preamble

This file is part of the Calendar package.
Copyright (C) 1996 Frank Bennett, Jr.
All rights reserved.
------------------------------------------
This is a generated file.

IMPORTANT NOTICE:

You are not allowed to change this file.  You may however copy
this file to a file with a different name and then change the
copy if (a) you do not charge for the modified code, (b) you
acknowledge the author(s) in the new file, if it
is distributed to others, and (c) you attach these same
conditions to the new file.

You are not allowed to distribute this file alone.  You are not
allowed to take money for the distribution or use of this file
(or a changed version) except for a nominal charge for copying
etc.

You are allowed to distribute this file under the condition that
it is distributed with all of its contents, intact.

For error reports, or offers to help make Calendar a more powerful,
friendlier, and better package, please contact me on
`fb' at soas.ac.uk

\endpreamble

\postamble
\endpostamble

\generate{\file{calendar.sty} {\from{calendar.dtx}{style}}
}

\Msg{***********************************************************}
\Msg{*}
\Msg{* To finish the installation, you have to move the following}
\Msg{* files into a directory searched by TeX:}
\Msg{*}
\Msg{* \space\space calendar.sty}
\Msg{*}
\Msg{* You will also need to have the following packages}
\Msg{* installed on your system before using this package}
\Msg{* or printing its documentation:}
\Msg{*}
\Msg{* \space\space overword.dtx}
\Msg{* \space\space dates.dtx}
\Msg{*}
\Msg{***********************************************************}

%</installer>
%    \end{macrocode}
%\fi
% \Finale \PrintChanges