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% Copyright (C) 2013 by Song Zhiwei <songzw@gmail.com>
% -----------------------------------------------------------
%
% This file may be distributed and/or modified under the conditions of
% the LaTeX Project Public License, either version 1.3c of this license
% or (at your option) any later version.  The latest version of this
% license is in:
%
%    http://www.latex-project.org/lppl.txt
%
% and version 1.3c or later is part of all distributions of LaTeX
% version 2006/05/20 or later.
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% \fi
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% \iffalse
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%<*driver>
\ProvidesFile{memory.dtx}
%</driver>
%<memory>\NeedsTeXFormat{LaTeX2e}[2003/12/01]
%<memory>\ProvidesPackage{memory}
%<*memory>
  [2013/05/13 v1.2 containers for data of object and array in LaTeX]
%</memory>
%<*driver>
\documentclass[a4paper]{ltxdoc}
\usepackage{memory}
\EnableCrossrefs
\CodelineIndex
\RecordChanges
\OnlyDescription
\begin{document}
  \DocInput{memory.dtx}
\end{document}
%</driver>
% \fi
%
% \CheckSum{69}
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% \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     \&
%   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         \~}
%
% \changes{v1.2}{2013/05/13}{Uses := to set the expanded value to a variable}
% \changes{v1.1}{2013/05/11}{Reports warning when redeclaring a variable}
% \changes{v1.0}{2013/05/10}{Initial version}
%
% \GetFileInfo{memory.dtx}
%
% \DoNotIndex{}
%
% \title{The \textsf{memory} package\thanks{This document
%        corresponds to \textsf{memory}~\fileversion, dated \filedate.}}
% \author{Song Zhiwei\\\texttt{songzw@gmail.com}}
%
% \maketitle
%
% \section{Introduction}
%
% The package memory.sty provides an easy way to declare object or array
% containers.
% If you are considering to use an auxiliary file, you really need
% this package rather than the heavy I/O manipulation.
%
% \section{Usage} 
% \newcommand\MyDescribeMacro[1]{\marginpar{\raggedleft\strut\MacroFont#1}}
% \DescribeMacro{\newdata\marg{variable}}
% \DescribeMacro{\newdata*\marg{variable}}
% These macros declare data variables locally and globally, respectively.
% The value for star version is also saved globally.
% \begin{verbatim}\newdata{Person}          % Note: no backslash for the variable declaration
%\newdata*{Time}\end{verbatim}\newdata{Person} \newdata*{Time}
% Uses = or := to set value. The := version sets the expanded value to variable.
% \MyDescribeMacro{\textbackslash\meta{var}\oarg{p}=\marg{value}}%
% \MyDescribeMacro{\textbackslash\meta{var}\oarg{p}:=\marg{value}}\\[0.5em]
% -- Sets value as a single variable.
% \begin{verbatim}\Person = {Song Zhiwei}   % Note: add backslash for declared variable
%\Time := \today\end{verbatim}
% \Person = {Song Zhiwei} \Time := \today
% -- Sets value as an array.
% \begin{verbatim}\Person[1] = {28.3}\end{verbatim}\Person[1] = {28.3}
% -- Sets value as a multiple dimensional array.
% \begin{verbatim}\Time[2,5,\thesection] = {13 May 2013}\end{verbatim}
% \Time[2,5,\thesection] = {13 May 2013}
% -- Sets value as an object.
% \begin{verbatim}\Person[description] = {A Chinese gentleman.}
%\Person[hair] = {black}\end{verbatim}
% \Person[description] = {A Chinese gentleman.}
% \Person[hair] = {black}
% -- Gets values.
% \MyDescribeMacro{\textbackslash\meta{variable}\oarg{p}}
% \begin{center}\newcommand\VRule{\rule[-0.2em]{0.4pt}{1.2em}}
% \verb|\Person|\hfill\VRule\quad\makebox[12em][l]{\Person}\\
% \verb|\Time|\hfill\VRule\quad\makebox[12em][l]{\Time}\\
% \verb|\Person[1]|\hfill\VRule\quad\makebox[12em][l]{\Person[1]}\\
% \verb|\Time[2,5,\thesection]|\hfill\VRule\quad\makebox[12em][l]{\Time[2,5,\thesection]}\\
% \verb|\Person[description]|\hfill\VRule\quad\makebox[12em][l]{\Person[description]}\\
% \verb|\Person[hair]|\hfill\VRule\quad\makebox[12em][l]{\Person[hair]}
% \end{center}
%
% \StopEventually{}
\def\set@memory#1#2=#3{\if#1*\expandafter\gdef\csname#2\endcsname{#3}%
                         \else\expandafter\def\csname#2\endcsname{#3}\fi}
\def\eset@memory#1#2=#3{\if#1*\expandafter\xdef\csname#2\endcsname{#3}%
                         \else\expandafter\edef\csname#2\endcsname{#3}\fi}
\def\etest@memory#1#2:{\@ifnextchar={\eset@memory{#1}{#2}}
                                    {\csname #2\endcsname:}}
\def\data@memory#1#2{\@ifnextchar={\set@memory{#1}{@#2@memory}}
                                  {\@ifnextchar:{\etest@memory{#1}{@#2@memory}}
                                                {\csname @#2@memory\endcsname}}}
\def\array@memory#1#2[#3]{\data@memory{#1}{#2@#3}}
\def\newdata@memory#1#2{\@ifundefined{#2}
  {\if#1*\expandafter\gdef\csname#2\endcsname{\@ifnextchar[
                          {\array@memory{#1}{#2}}{\data@memory{#1}{#2}}}%
   \else \expandafter\def\csname#2\endcsname{\@ifnextchar[
                          {\array@memory{#1}{#2}}{\data@memory{#1}{#2}}}\fi}
  {\PackageWarningNoLine{memory}{`#2' already defined.
                                 Macro `newdata' ignored!}}}
\def\newdata{\@ifnextchar*{\newdata@memory}{\newdata@memory{}}}
% \Finale
\endinput