% \section{Date Syntax}
%
% \subsection{General Rules}
%
% The rules themselves are explained here first.  If you
% want to cut to the chase, have a look at the examples
% and experiment a bit with the demo file.  It's all
% pretty straightforward.
%
% The parser is indifferent to extra spaces and blank
% lines in dates.  It will read a string word by word,
% and classify each word as a time, a day of the month,
% the name of a month, a year or a special function.
% With two exceptions, strings beginning in a number must not mix numbers and
% other characters --- this will produce a low-level
% error from \TeX, and at the moment I can't think of
% an economical way of protecting against this.
%
% Any string
% beginning in a number is interpreted as either a
% time, a day of the month or a year.  A string
% containing a colon (the ":" character) is assumed
% to be a time of day.  "AM" and "PM" are not recognized;
% you should use 24-hour format when specifying
% times.  A numeric string containing a hyphen is assumed
% to be a range of times.  In this instance, a colon
% is not necessary if the time is given in whole-hours.
% Pure numeric strings are construed as a day of the month
% if less than 32, or as a year if greater than 31.
%
% Character strings are interpreted on the basis of their
% first three characters; the rest are ignored.  Case is
% also irrelevant.  Months and days of the week (used for
% defining recursive dates, described below) as well as certain
% special functions are specified as character strings.
% Any word that does not match an existing function
% will be ignored.
%
% Dates are always terminated by a short description
% of the date, which must be in curly braces.
% The description should contain plain text only;
% do not put macros (like "\LaTeX") here.
%
% Dates will be processed until "\dateread" encounters
% "\end{<"\meta{environment name}">}", or the string
% "\relax{}".  At the "\end" of an environment,
% the processing of the current date will be completed,
% and the "\end" will be executed.  "\relax{}" will
% cause processing to end silently without doing
% anything on the last item (which is the "\relax{}" itself).
%
% \subsection{Specific Dates}
%
% Applying the above rules, the following is a valid
% list of dates.  The use of "\dateread" is explained
% below.
%
% \begin{quote}
% \begin{verbatim}
% \begin{quote}
% \dateread{\message{\theshorttext}}
% Jan 1 1996{New Year's Day}
%      1    January 1996 at 10:00
%          {New Year Bash}"\\
% 1996
%     jan 1 8-20:30
%     {New Year Cleaning. Rats.}"
% \end{quote}
% \end{verbatim}
% \end{quote}
%
% Note that the parser is indifferent to word order,
% and that commas should not be used to separate
% words.\footnote{In fact, commas do no harm if
% they follow a string of three or more letters, but
% it is best to keep things simple and clean.}
%
% \subsection{Recursive Dates}
%
% \subsubsection{Ranges}
%
% Any recursive dates (such as "Every" "Monday") must
% be preceded by one or more range specifications,
% which fix the time period or periods within which to
% recurse.
% A range is simply two specific dates separated by the
% word "to".  You may specify multiple ranges;
% effect will be given to each of them individually.
%
% The following is a valid range specification:
%
% \begin{quote}
% \begin{verbatim}
%    February  1 1996 {Start First Period}
% to April     1 1996 {End First Period}
%    November  3 1996 {Start Second Period}
% to December 24 1996 {End Second Period}
% \end{verbatim}
% \end{quote}
%
% \subsubsection{Shorthand Dates}
%
% Two types of recursive date can be entered in a
% human-readable syntax.  Entries of both types
% begin with the word "every".  To put an event
% on every occurence of a day of the week within
% a specified set of subranges, simply indicate the day
% of the week, followed by a short description
% in curly braces.
%
% \begin{quote}
% \begin{verbatim}
% Every Monday {Monday!}
% \end{verbatim}
% \end{quote}
%
% To put an event at 14-day intervals, beginning
% with the first occurrence of a specified day
% of the week within each subrange, add the
% word "other".
%
% \begin{quote}
% \begin{verbatim}
% Every other Monday 7:00 {Monday Morning Exercise}
% \end{verbatim}
% \end{quote}
%
% To place an event on the "N"th occurrence of
% a specified day of the week within each month, within
% subrange, add "first", "second" or "third".
%
% \begin{quote}
% \begin{verbatim}
% Every third Monday 8:00-9:00
%   {Monday Morning Meeting}
% \end{verbatim}
% \end{quote}
%
% \subsubsection{Suppressing the Action}
%
% There are two ways of suppressing the user-defined action.
% To quickly comment out an entry, put the word "rem" in
% front of it.  The date will be read, but the action
% in the argument to "\dateread" will not be performed.
% This can be used, for example, to suppress the appearance
% of a range in the output text.
%
% The second method uses a toggle, and is meant for use by
% style authors.  Setting:
%
% \begin{quote}
% "\dates@suppress@globaltrue"
% \end{quote}
%
% \noindent will cause the user action to be suppressed
% throughout the invocation of "\dateread".  In order for
% the action to be performed on the next invocation,
% the toggle must be set to "false" in the external
% code that calls the parser.
%
% \subsubsection{Functions}
%
% It is possible to specify dates within the subranges
% using an arbitrary formula.  Entries of this type
% begin with the word "function".  This is followed
% by two control strings, a block of \LaTeX{} code in
% curly braces, and the usual short description, also in
% curly braces.
%
% The first control string is the name of a
% user-defined macro that will find the position
% of the first desired date after the start of the
% range.  The second is the name of a macro to
% use in incrementing afterward.  The block of
% \LaTeX{} code contains the definitions of these
% and any subsidiary macros.
%
% The following will place an entry on every date within
% the specified subranges.
%
% \begin{quote}
% \begin{verbatim}
% Function \myinit \myincrement
%  {\def\myinit{%
%    \dates@date=\dates@subrange@start}
%   \def\myincrement{%
%    \advance\dates@date by 1\relax}
%  }
%  {A Day}
% \end{verbatim}
% \end{quote}
%
% See the code commentary section of the Dates package for information
% on macros that can be used for manipulating dates.