% \iffalse meta-comment
%
% Copyright 1989-2001 Johannes L. Braams and any individual authors
% listed elsewhere in this file.  All rights reserved.
% 
% This file is part of the Babel system release 3.7.
% --------------------------------------------------
% 
% It may be distributed under the terms of the LaTeX Project Public
% License, as described in lppl.txt in the base LaTeX distribution.
% Either version 1.2 or, at your option, any later version.
% \fi
%% \CheckSum{116}
%% \CharacterTable
%%  {Upper-case    \A\B\C\D\E\F\G\H\I\J\K\L\M\N\O\P\Q\R\S\T\U\V\W\X\Y\Z
%%   Lower-case    \a\b\c\d\e\f\g\h\i\j\k\l\m\n\o\p\q\r\s\t\u\v\w\x\y\z
%%   Digits        \0\1\2\3\4\5\6\7\8\9
%%   Exclamation   \!     Double quote  \"     Hash (number) \#
%%   Dollar        \$     Percent       \%     Ampersand     \& ^^A$
%%   Acute accent  \'     Left paren    \(     Right paren   \)
%%   Asterisk      \*     Plus          \+     Comma         \,
%%   Minus         \-     Point         \.     Solidus       \/
%%   Colon         \:     Semicolon     \;     Less than     \<
%%   Equals        \=     Greater than  \>     Question mark \?
%%   Commercial at \@     Left bracket  \[     Backslash     \\
%%   Right bracket \]     Circumflex    \^     Underscore    \_
%%   Grave accent  \`     Left brace    \{     Vertical bar  \|
%%   Right brace   \}     Tilde         \~}
%\iffalse
%
%% This is file `athnum.dtx'
%% (c) 1997-2001 Apostolos Syropoulos.
%% All rights reserved.
%
%  Please report errors or suggestions for improvement to
%    
%    Apostolos Syropoulos
%    366, 28th October Str.
%    GR-671 00 Xanthi, GREECE
%    apostolo@platon.ee.duth.gr or apostolo@obelix.ee.duth.gr
%
%\fi
%
% \iffalse
%    \begin{macrocode}
%<*driver>
\documentclass{ltxdoc}
\def\PiIt#1{{%
    \newdimen\boxW \newdimen\boxH
    \settowidth{\boxW}{#1}%
    \settoheight{\boxH}{#1}%
    \addtolength{\boxW}{0.8pt}
    \vbox{%
    \hrule width\boxW\hbox{%
          \vrule height\boxH\mbox{#1}%
          \vrule height\boxH}}\kern.5pt}}
\GetFileInfo{athnum.drv}
\begin{document}
   \DocInput{athnum.dtx}
\end{document}
%</driver>
%    \end{macrocode}
% \fi
%
%\title{Athenian Numerals II\footnote{The documentation of this 
% package is essentially the same as that of the package `grnumalt'.
% The `II' serves as a means to distinguish the two documents.}}
%\author{Apostolos Syropoulos\\366, 28th October Str.\\
%GR-671 00 Xanthi, HELLAS\\ Email:\texttt{apostolo@platon.ee.duth.gr}}
% \date{1997/09/21}
%\maketitle
% 
%\MakeShortVerb{\|}
%
%\section{Introduction}
% 
% This \LaTeX\ package implements the macro 
% \DescribeMacro{\athnum}
% |\athnum|. The macro transforms an Arabic numeral, i.e., the kind
% of numerals we all use (e.g., 1, 5, 789 etc), to the corresponding
% {\itshape Athenian} numeral. Athenian numerals were in use only in 
% ancient Athens. The package can be used only in conjunction with the 
% |greek| option of the |babel| package.
%
%\section{The Numbering System}
%
% The athenian numbering system, like the roman one, employs
% letters to denote important numbers. Multiple occurrence of a letter denote
% a multiple of the ``important'' number, e.g., the letter I denotes 1, so
% III denotes 3. Here are the basic digits used in the Athenian numbering
% system:
% \begin{itemize}
%  \item I denotes the number one (1)
%  \item $\Pi$ denotes the number five (5)
%  \item $\Delta$ denotes the number ten (10)
%  \item H denotes the number one hundred (100)
%  \item X denotes the number one thousand (1000) 
%  \item M denotes the number ten thousands (10000)
%\end{itemize}
% Moreover,  the letters $\Delta$, H, X, and M under the letter $\Pi$, 
% denote five times their original value, e.g., the symbol 
% \PiIt{X}, denotes the number 5000, and the symbol  
% \PiIt{$\Delta$}, denotes the number 50. It must be noted that
% the numbering system does not provide negative numerals or a symbol for
% zero. 
%
% The Athenian numbering system is described, among others, in an article in
% Encyclopedia $\Delta o\mu\acute{\eta}$, Vol. 2, page 280, 7th edition,
% Athens, October 2, 1975.
%
% \section{The Code}  
% Before we do anything further, we have to identify the package.
% \StopEventually
%
%    \begin{macrocode}
%<*package>
\NeedsTeXFormat{LaTeX2e}[1996/01/01]
\ProvidesPackage{athnum}[1997/09/22\space v1.0]
\typeout{Package: `athnum' v1.0\space <1997/09/22> (A. Syropoulos)}
%    \end{macrocode}
% Next we check to see if the |babel| package is loaded with at least
% the |greek| option. In case it isn't, we opt to produce an error message.
%    \begin{macrocode} 
\@ifpackagewith{babel}{greek}{}{%
   \@ifpackagewith{babel}{polutonikogreek}{}{%
     \PackageError{athnum}{%
     `greek' option of the `babel'\MessageBreak
      package hasn't been loaded}{%
      The commands provided by this package\MessageBreak
      are specially designed for greek language\MessageBreak
      typesetting with the `babel' package. Load\MessageBreak
      it with at least the `greek' option.}\relax
      }}
%    \end{macrocode}
%
% As it is mentioned in the introduction, the Athenian numerals employ
% some special digits. These digits are included in the |cb| fonts of
% Claudio Beccari, and so we must provide access commands.
%    \begin{macrocode}
\DeclareTextCommand{\PiDelta}{LGR}{\char"02\relax}
\DeclareTextCommand{\PiEta}{LGR}{\char"03\relax}
\DeclareTextCommand{\PiChi}{LGR}{\char"04\relax}
\DeclareTextCommand{\PiMu}{LGR}{\char"05\relax}
%    \end{macrocode}
%\begin{macro}{\athnum}            
% Now, we turn our attention to the definition of the macro 
% |\athnum|. This macro uses one integer variable (or counter in 
% \TeX's jargon.)
%    \begin{macrocode}
\newcount\@ath@num
%    \end{macrocode}
% The macro |\athnum| is also defined as a robust command.
%    \begin{macrocode}
\DeclareRobustCommand*{\athnum}[1]{%
%    \end{macrocode}
% After assigning to variable |\@ath@num| the value of the macro's argument, we
% make sure that the argument is in the expected range, i.e., it is greater
% than zero, and less or equal to $249999$.  In case it isn't, we simply 
% produce a |\space|, warn the user about it and quit. Although, the
% |\athnum| macro is capable to produce an Athenian numeral for even greater
% intergers, the following argument by Claudio Beccari convised me to place
% this above upper limit:
% \begin{quote} 
% According to psychological perception studies (that ancient Athenians
% and Romans perfectly knew without needing to study Freud and Jung)
% living beings (which includes at least all vertebrates, not only
% humans) can perceive up to four randomly set objects of the same kind   
% without the need of counting, the latter activity being a specific
% acquired ability of human kind; the biquinary numbering notation
% used by the Athenians and the Romans exploits this natural
% characteristic of human beings.
% \end{quote}
%    \begin{macrocode}
        \@ath@num#1\relax
        \ifnum\@ath@num<\@ne%
          \space%
          \PackageWarning{athnum}{%
          Illegal value (\the\@ath@num) for athenian numeral}%
        \else\ifnum\@ath@num>249999%
          \space%
          \PackageWarning{athnum}{%
          Illegal value (\the\@ath@num) for athenian numeral}%
        \else
%    \end{macrocode}
% Having done all the necessary checks, we are now ready to do the actual
% computation. If the number is greater than $49999$, then it certainly
% has at least one \PiIt{M} ``digit''. We find all such digits by continuously
% subtracting $50000$ from |\@ath@num|, until |\@ath@num| becomes less than
% $50000$. 
%    \begin{macrocode}
            \@whilenum\@ath@num>49999\do{%
               \PiMu\advance\@ath@num-50000}%
%    \end{macrocode}
% We now check for tens of thousands.
%    \begin{macrocode}
            \@whilenum\@ath@num>9999\do{%
               M\advance\@ath@num-\@M}%
%    \end{macrocode}
% Since a number can have only one \PiIt{X} ``digit'' (equivalent to 5000), it 
% is easy to check it out and produce the corresponding numeral in case it does
% have one.
%    \begin{macrocode}
            \ifnum\@ath@num>4999%
               \PiChi\advance\@ath@num-5000%
            \fi\relax
%    \end{macrocode}
% Next, we check for thousands, the same way we checked for tens of thousands.
%    \begin{macrocode}
            \@whilenum\@ath@num>999\do{%
               Q\advance\@ath@num-\@m}%
%    \end{macrocode}
% Like the five thousands, a numeral can have at most one \PiIt{H} ``digit''
% (equivalent to 500).
%    \begin{macrocode}
            \ifnum\@ath@num>499%
               \PiEta\advance\@ath@num-500%
            \fi\relax
%    \end{macrocode}
% It is time to check hundreds, which follow the same pattern as thousands
%    \begin{macrocode}
            \@whilenum\@ath@num>99\do{%
               H\advance\@ath@num-100}%
%    \end{macrocode}
% A numeral can have only one \PiIt{$\Delta$} ``digit'' (equivalent to 50).
%    \begin{macrocode} 
            \ifnum\@ath@num>49%
               \PiDelta\advance\@ath@num-50%
            \fi\relax
%    \end{macrocode}
% Let's check now decades.
%    \begin{macrocode}         
            \@whilenum\@ath@num>9\do{%
               D\advance\@ath@num by-10}%
%    \end{macrocode}
% We check for five and, finally, for the digits 1, 2, 3, and 4.
%    \begin{macrocode}
            \@whilenum\@ath@num>4\do{%
               P\advance\@ath@num-5}%
            \ifcase\@ath@num\or I\or II\or III\or IIII\fi%
   \fi\fi}
%    \end{macrocode}
% \DescribeMacro{\@athnum} The command |\@athnum| is defined just to make
% it possible to have, e.g., page numbering with athenian numerals.
%    \begin{macrocode}
\let\@athnum\athnum 
%</package>
%    \end{macrocode}
%\end{macro}
%
% \section*{Acknowledgment}
% I would like to thank Claudio Beccari for reading the documentation
% and for his very helpful suggestions.
% \section*{Dedication}
% I would like to dedicate this piece of work to my son 
% \begin{center}Demetrios-Georgios.\end{center}
% \Finale
%
\endinput