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%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5
% Bundled source file for the IFMTARG package
%--------1---------2---------3---------4---------5
% Please see the accompanying README for author,
% license, documentation and installation information
%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5
\RequirePackage{filecontents}
\begin{filecontents*}{ifmtarg.sty}
\NeedsTeXFormat{LaTeX2e}
\ProvidesPackage{ifmtarg}[2018/04/16 v1.2b check for an empty argument]
\begingroup
\catcode`\Q=3
\long\gdef\@ifmtarg#1{\@xifmtarg#1QQ\@secondoftwo\@firstoftwo\@nil}
\long\gdef\@xifmtarg#1#2Q#3#4#5\@nil{#4}
\long\gdef\@ifnotmtarg#1{\@xifmtarg#1QQ\@firstofone\@gobble\@nil}
\endgroup
\endinput
\end{filecontents*}
%%%%%%%%%1%%%%%%%%%2%%%%%%%%%3%%%%%%%%%4%%%%%%%%%5
% Conditionally compile the documentation & generate the .ins file:
\providecommand\documentationCompile{Y}
\makeatletter
\if\documentationCompile N
\expandafter\@@end
\fi
\begin{filecontents*}{ifmtarg.ins}
%&latex
\def\documentationCompile{N}
\input ifmtarg.tex
\csname@@end\endcsname
\end{filecontents*}
\makeatletter
\documentclass[twocolumn]{ltxdoc}
\usepackage{shortvrb}
\MakeShortVerb\|
\usepackage[it,medium]{titlesec}
\usepackage{array,ifmtarg,bigfoot,fancyvrb}
\usepackage[svgnames]{xcolor}
\usepackage[colorlinks,linktocpage]{hyperref}
\usepackage{geometry}
\geometry{margin=2cm}
\usepackage{tocloft,varwidth}
\setcounter{tocdepth}{1}
\def\tocwidthA{0.55}
\def\tocwidthB{0.44}
\def\cftpartfont{\scshape}
\def\cftsecfont{\small}
\cftbeforesecskip=0pt
\def\cftpartleader{}
\def\cftpartafterpnum{\cftparfillskip}
\def\cftsecleader{}
\def\cftsecafterpnum{\cftparfillskip}
\DeclareRobustCommand\pkg{\textsf}
\def\pkgopt#1{\texttt{[#1]}}
\newcommand\chng[1]{\marginpar{\footnotesize\raggedright\textsf{#1}}}
\def\PDF{\textsc{pdf}}
\def\PS{\textsc{ps}}
\def\DVI{\textsc{dvi}}
\def\EPS{\textsc{eps}}
\usepackage{amsmath,listings}
\lstset{basicstyle=\ttfamily,columns=fullflexible}
\usepackage{changepage}
\usepackage[T1]{fontenc}
\usepackage{microtype}
\usepackage{lmodern}
\usepackage[sc,osf]{mathpazo}
\linespread{1.1}
\frenchspacing
\GetFileInfo{ifmtarg.sty}
\begin{document}
{\addtocontents{toc}{\protect\begin{varwidth}[t]{\tocwidthA\linewidth}}}
\title{The \pkg{ifmtarg} package}
\author{%
Author: Donald Arseneau, and Peter Wilson, Herries Press\\
Maintainer: Will Robertson\\
\texttt{will dot robertson at latex-project dot org}%
}
\date{\fileversion \qquad \filedate}
\maketitle
\section{Documentation}
The \pkg{ifmtarg} package provides an if--then--else programmer's command \verb|\@ifmtarg| for testing for an empty macro argument.
`Empty' here refers to an argument of zero or more spaces only.\footnote{If you need a command to test for emptiness that doesn't include spaces, use the \verb|\tl_if_empty:nTF| conditional from the \pkg{expl3} package. \verb|\@ifmtarg| is equivalent to \pkg{expl3}'s \verb|\tl_if_blank:nTF|.}
The command is fully expandable; its syntax is:
\begin{quote}
\cmd{\@ifmtarg}\marg{arg}\marg{Code for arg empty}
\\\null\hfill
\marg{Code for arg not empty}
\end{quote}
A variation is provided, \cmd{\@ifnotmtarg}, to be used when only the `false' branch is required.
It is slightly more efficient when code is only required for a non-empty argument.
\begin{quote}
\cmd{\@ifnotmtarg}\marg{arg}\marg{Code for not empty}
\end{quote}
\section{Examples}
\begin{verbatim}
\newcommand\isempty[1]{\@ifmtarg{#1}{YES}{NO}}
\end{verbatim}
\nobreak
\begin{tabular}{@{\hspace{1.8em}}>{\color{SeaGreen}}l@{$\quad\to\quad$}>{\ttfamily}l@{}}
\verb+\isempty{}+ & YES \\
\verb+\isempty{ }+ & YES \\
\verb+\isempty{E}+ & NO \\
\verb+\isempty{ E }+ & NO
\end{tabular}
\begin{verbatim}
\newcommand\isnotempty[1]{\@ifnotmtarg{#1}{YES}}
\end{verbatim}
\nobreak
\begin{tabular}{@{\hspace{1.8em}}>{\color{SeaGreen}}l@{$\quad\to\quad$}>{\ttfamily}l@{}}
\verb+\isnotempty{}+ & \\
\verb+\isnotempty{ }+ & \\
\verb+\isnotempty{E}+ & YES \\
\verb+\isnotempty{ E }+ & YES
\end{tabular}
\newpage
\section{History}
(\emph{Peter's comments follow.}) In an Email to me on 13 March 2000, Donald Arseneau pointed out some
failings with my original definition of the \cmd{\@ifmtarg} command:
%
\begin{verbatim}
\newcommand{\@ifmtarg}[3]{%
\edef\@mtarg{\zap@space#1 \@empty}%
\ifx\@empty\@mtarg\relax #2\else #3\fi}
\end{verbatim}
%
It works most of the time correctly but Donald showed that it can
give unexpected results
under conditions that I had not thought of. He suggested the coding
that now appears in the package above for the \cmd{\@ifmtarg} and
\cmd{\@ifnotmtarg} commands. For a discussion on detecting empty arguments
see \href{http://www.ctan.org/pub/tex-archive/info/aro-bend/answer.002}{\texttt{CTAN/info/aro-bend/answer.002}}
\section*{Change History}
\begin{itemize}
\item[v1.2a] New maintainer (Will Robertson)
\item[v1.2b] Typo in documentation example code
\end{itemize}
\section*{Licence and copyright}
This work may be modified and/or distributed under the terms and
conditions of the \LaTeX\ Project Public License\footnote{\url{http://www.latex-project.org/lppl.txt}}, version~1.3c or later (your choice).
The current maintainer of this work is Will Robertson.
\bigskip
\noindent
Copyright Peter Wilson, 1996 \\
Copyright Peter Wilson and Donald Arseneau, 2000
{\addtocontents{toc}{\protect\end{varwidth}\protect\hfill}}
{\addtocontents{toc}{\protect\begin{varwidth}[t]{\protect\tocwidthB\protect\linewidth}}}
\clearpage
\parindent=0pt
\section{Implementation}
\VerbatimInput{ifmtarg.sty}
{\addtocontents{toc}{\protect\end{varwidth}}}
\end{document}
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