%TUGBoat article A Multienumerate Package

\documentclass{article}
\usepackage{multicol,multienum}
\pagestyle{headings}
\begin{document}
\title{A Multienumerate Package}
\author{Dennis Kletzing\\Stetson University} \date{\today}
\maketitle
\begin{abstract}
{\it The {\tt multienum.sty} package  allows
the user to produce an enumerated array of multiple
columns, each vertically aligned on the counter. An optional
argument provides  for consecutive numbering of the array items,
or an even-only or odd-only numbering scheme.}
\end{abstract}
Typesetting the solutions manual for a text frequently involves creating an
enumerated list involving many short answers. Typically these are set with
several items per
line, with no attempt made to vertically align the exercise numbers. The
{\tt multienum.sty} package provides an environment, {\tt multienumerate},
that produces  an enumerated array in which columns are vertically aligned
on the counter. If the user wishes, the enumeration counter can
 be changed to give a list of even-only  numbers or odd-only
 numbers.

\begin{table}[b]
\caption{An enumerate array  of solutions}
\parbox[t]{.99\hsize}{%
\hrule\hrule
\begin{multienumerate}
\mitemxxxx{Not}{Linear}{Not}{Quadratic}
\mitemxxxo{Not}{Linear}{No; if $x=3$, then $y=-2$.}
\mitemxx{$(x_1,x_2)=(2+\frac{1}{3}t,t)$ or
$(s,3s-6)$}{$(x_1,x_2,x_3)=(2+\frac{5}{2}s-3t,s,t)$}
\mitemx{$(x_1,x_2,x_3,x_4)= (\frac{1}{4}+\frac{5}{4}s+\frac{3}{4}t-u,s,t,u)$
or $(s,t,u,\frac{1}{4}-s+\frac{5}{4}t+\frac{3}{4}u)$}
\mitemxxxx{$(2,-1,3)$}{None}{$(2,1,0,1)$}{$(0,0,0,0)$}
\end{multienumerate}}\hrule
\end{table}

\section*{What the package does}
Table 1 shows  a typical enumerated array. The fourth entry in
the second row is left blank since the next item is too long to
fit in space. The third row has only two entries. To get the
vertical alignment of the counter in column 3, we set row three
as  four entries, but left entry 2 and entry 4 blank thus
giving more space for the first and third entries. To produce
the enumerated array shown above, we typed the following:




\begin{verbatim}
  \begin{multienumerate}
  \mitemxxxx{Not}{Linear}{Not}{Quadratic}
  \mitemxxxo{Not}{Linear}{Not}
  \mitemxx{$(x_1,x_2)=(2+\frac{1}{3}t,t)$ or
    $(s,3s-6)$}{$(x_1,x_2,x_3)=(2+\frac{5}{2}s-3t,s,t)$}
  \mitemx{$(x_1,x_2,x_3,x_4)=
    (\frac{1}{4}+\frac{5}{4}s+\frac{3}{4}t-u,s,t,u)$
    or $(s,t,u,\frac{1}{4}-s+\frac{5}{4}t+\frac{3}{4}u)$}
  \mitemxxxx{$(2,-1,3)$}{None}{$(2,1,0,1)$}{$(0,0,0,0)$}
  \end{multienumerate}
\end{verbatim}
The environment {\tt multienumerate} has an optional argument
for enumerating even-only or odd-only  arrays.\footnote{The
optional arguments works only in \LaTeX2e.}

\begin{itemize}
\item \verb|\begin{multienumerate} ... \end{multienumerate}|
\item[]   produces a consecutively enumerated  array
\item \verb|\begin{multienumerate}[evenlist] ...\end{multienumerate}|
\item[]  produces an enumerated  array using only even numbers
\item \verb|\begin{multienumerate}[oddlist] ...\end{multienumerate}|
\item[]  produces an enumerated  array using only odd numbers
\end{itemize}

\section*{Using the package}
Each row of the enumerated  array is set using
one of the nine commands:

\begin{small}
\renewcommand{\arraystretch}{1.2}%1.4
\begin{tabular}{@{}lp{3in}}
\verb|\mitemx{}|&A single item in the row.\\
\verb|\mitemxx{}{}|&Two items in the row.\\
\verb|\mitemxxx{}{}{}|&Three items in the row.\\
\verb|\mitemxox{}{}|&Three items in the row with the
center item space left blank so the first item can extend
into its space.\\
\verb|\mitemxxo{}{}|&Three items in the row with the last
item left blank so the second item can extend into
 its space.\\
\verb|\mitemxxxx{}{}{}{}|&Four items in the row.\\
\verb|\mitemxoxx{}{}{}|& Four items in the row with the
second space left blank so the first item can extend into
its space.\\
\verb|\mitemxxox{}{}{}|&Four items in the row with the
third space left blank so the second item can extend into
its space.\\
\verb|\mitemxxxo{}{}{}|&Four items in the row with the
last space left blank so the third item can extend into
its space.
\end{tabular}
\end{small}

For example, \verb|\mitemxxx{a}{b}{c}| sets three items, a, b, c equally
spaced  across the row; \verb|\mitemxox{a}{c}| sets the two
items, a and c, across the row {\em as if\/} there were three items, leaving
the second entry blank so that the first entry can extend into
its space; and \verb|\mitemxxo{a}{b}| sets the two items, a and
b, {\em as if\/} there were three items, but leaves the space
for the third item blank, allowing the second entry to extend
into its space.

A convenient way to use the multienumerate
package is with a two column layout using multicols. Page 7
illustrates  a typical page from a solutions manual  set in
two columns format using multicols and multienumerate.

A disadvantage of the package is that the user must choose how
to typeset each line in the array rather than letting \TeX\
decide how to do it. This creates a lot of overhead in the
macro since separate commands are needed for each possibility.
It is not difficult to write a macro that will let
 \TeX\  decide how many items to set on each line. This
approach, while the most efficient, does not always give the
visual appearance that the user may want.


\section{How the package works}
We illustrate how the package typesets a line
containing two items. The other
situations are similar.

\noindent
\setlength{\unitlength}{1.3pt}
\begin{picture}(240,50)(0,0)


\put(0,0){\framebox(35,10)[b]{\hfill 1.}}
\put(40,0){\framebox(30,10)[b]{}}
\put(75,0){\framebox(50,10)[bl]{stuff}}

\put(0,30){\makebox(35,10)[b]{\small
\texttt{$\backslash$labelwidth}}}
\put(40,30){\makebox(30,10)[b]{\small
\texttt{$\backslash$labelsep}}}
\put(75,30){\makebox(50,10)[b]{\small
\texttt{$.5\backslash$remainxx}}}

\put(17.5,20){\vector(-1,0){17.5}}
\put(17.5,20){\vector(1,0){17.5}}

\put(55,20){\vector(-1,0){15}}
\put(55,20){\vector(1,0){15}}

\put(100,20){\vector(-1,0){25}}
\put(100,20){\vector(1,0){25}}

\put(147.5,20){\vector(-1,0){17.5}}
\put(147.5,20){\vector(1,0){17.5}}

\put(185,20){\vector(-1,0){15}}
\put(185,20){\vector(1,0){15}}

\put(230,20){\vector(-1,0){25}}
\put(230,20){\vector(1,0){25}}

\put(130,0){\framebox(35,10)[b]{\hfill 2.}}
\put(170,0){\framebox(30,10)[b]{}}
\put(205,0){\framebox(50,10)[bl]{stuff}}

\put(130,30){\makebox(35,10)[b]{\small
\texttt{$\backslash$labelwidth}}}
\put(170,30){\makebox(30,10)[b]{\small
\texttt{$\backslash$labelsep}}}
\put(205,30){\makebox(50,10)[b]{\small
\texttt{$.5\backslash$remainxx}}}
\end{picture}

\bigskip
The total width of the line is then set equal to \verb|\hsize|:
\[\underbrace{2\texttt{$\backslash$labelwidth}+
2\texttt{$\backslash$labelsep}}_{\texttt{$\backslash$usedxx}}+
\texttt{$\backslash$remainxx}=\texttt{$\backslash$hsize}\]
\[\texttt{$\backslash$remainxx}=
\texttt{$\backslash$hsize}-
\texttt{$\backslash$usedxx}\]

\bigskip
In this way the macro determines the width of each box
 when two items are typeset on the line.

\section{The macro}
Here is the package \texttt{multienum.sty}.
\begin{verbatim}
\setlength{\hsize}{\textwidth}

%First define new lengths

\newlength{\usedx}
\newlength{\remainx}
\newlength{\usedxx}
\newlength{\remainxx}
\newlength{\usedxxx}
\newlength{\remainxxx}
\newlength{\usedxxxx}
\newlength{\remainxxxx}
\newlength{\remainxox}
\newlength{\remainxoxx}

%Define new item control sequences

\newcommand{\itemx}[1]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep%
\parbox[t]{\remainx}{\raggedright #1}\smallskip}

\newcommand{\itemxx}[2]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{.5\remainxx}{\raggedright #1}\hfill\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.5\remainxx}{\raggedright #2}\smallskip}

\newcommand{\itemxxx}[3]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep%
\parbox[t]{.3333\remainxxx}{\raggedright #1}\hfill\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep%
\parbox[t]{0.3333\remainxxx}{\raggedright #2}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep%
\parbox[t]{0.3333\remainxxx}{\raggedright #3}\smallskip}

\newcommand{\itemxxxx}[4]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{.25\remainxxxx}{\raggedright #1}\hfill\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #2}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #3}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #4}\smallskip}

\newcommand{\itemxox}[2]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{\remainxox}{\raggedright #1}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.3333\remainxxx}{\raggedright #2}\smallskip}

\newcommand{\itemxxo}[2]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.3333\remainxxx}{\raggedright #1}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{\remainxox}{\raggedright #2}\smallskip}

\newcommand{\itemxoxx}[3]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{\remainxoxx}{\raggedright #1}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #2}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #3}\smallskip}

\newcommand{\itemxxox}[3]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{.25\remainxxxx}{\raggedright #1}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{\remainxoxx}{\raggedright #2}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{0.25\remainxxxx}{\raggedright #3}\smallskip}

\newcommand{\itemxxxo}[3]{\parbox[t]%
{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{.25\remainxxxx}{\raggedright #1}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{.25\remainxxxx}{\raggedright #2}\hfill%
\parbox[t]{\labelwidth}{\hfill\labelenumi}\hskip\labelsep
\parbox[t]{\remainxoxx}{\raggedright #3}\smallskip}

\newcommand{\mitemx}[1]{\item[] \itemx{#1}}
\newcommand{\mitemxx}[2]{\item[] \itemxx{#1}{#2}}
\newcommand{\mitemxxx}[3]{\item[] \itemxxx{#1}{#2}{#3}}
\newcommand{\mitemxox}[2]{\item[] \itemxox{#1}{#2}}
\newcommand{\mitemxxo}[2]{\item[] \itemxxo{#1}{#2}}
\newcommand{\mitemxxxx}[4]{\item[] \itemxxxx{#1}{#2}{#3}{#4}}
\newcommand{\mitemxoxx}[3]{\item[] \itemxoxx{#1}{#2}{#3}}
\newcommand{\mitemxxox}[3]{\item[] \itemxxox{#1}{#2}{#3}}
\newcommand{\mitemxxxo}[3]{\item[] \itemxxxo{#1}{#2}{#3}}
\newcommand{\mitemxxoo}[2]{\item[] \itemxxoo{#1}{#2}}

%Create counter options

\newcommand{\oddlist}{\setcounter{enumi}{-1}
\renewcommand{\labelenumi}
{\ifodd\value{enumi}\addtocounter{enumi}{2}%
\arabic{enumi}.\else
\addtocounter{enumi}{1}\arabic{enumi}.%
\addtocounter{enumi}{-2}\fi}}

\newcommand{\evenlist}{\setcounter{enumi}{0}
\renewcommand{\labelenumi}
{\ifodd\value{enumi}\addtocounter{enumi}{1}\arabic{enumi}.%
\addtocounter{enumi}{-2}\else
\addtocounter{enumi}{2}\arabic{enumi}.\fi}}

\newcommand{\regularlist}{\setcounter{enumi}{0}
\renewcommand{\labelenumi}
{\addtocounter{enumi}{1}\arabic{enumi}.}}

\newcommand{\listtype}[1]{#1}

%Create the environment

\newenvironment{multienumerate}[1][\regularlist]{%
\listtype{#1}
\begin{trivlist}%
\setlength{\labelwidth}{18pt}
\setlength{\labelsep}{5pt}%
\setlength{\usedx}{\labelwidth}%
\addtolength{\usedx}{\labelsep}%
\setlength{\remainx}{\hsize}%
\addtolength{\remainx}{-\usedx}%
\setlength{\usedxx}{2\labelwidth}%
\addtolength{\usedxx}{2\labelsep}%
\setlength{\remainxx}{\hsize}%
\addtolength{\remainxx}{-\usedxx}%
\setlength{\usedxxx}{3\labelwidth}%
\addtolength{\usedxxx}{3\labelsep}%
\setlength{\remainxxx}{\hsize}%
\addtolength{\remainxxx}{-\usedxxx}%
\setlength{\usedxxxx}{4\labelwidth}%
\addtolength{\usedxxxx}{4\labelsep}%
\setlength{\remainxxxx}{\hsize}%
\addtolength{\remainxxxx}{-\usedxxxx}%
\setlength{\remainxox}{.666\remainxxx}%
\addtolength{\remainxox}{\labelwidth}%
\addtolength{\remainxox}{\labelsep}%
\setlength{\remainxoxx}{.5\remainxxxx}%
\addtolength{\remainxoxx}{\labelwidth}%
\addtolength{\remainxoxx}{\labelsep}%
\setlength{\itemindent}{0pt}}{\end{trivlist}}

%%End of file `multienum.sty'
\end{verbatim}
\pagebreak

\markboth{}{SAMPLE}
\subsection*{Answers to Even Exercises}
\begin{multicols}{2}
\subsection*{Chapter 1}
\subsection*{Section 1}
\begin{multienumerate}[evenlist]
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{2}{5}{$-4$}
\end{multienumerate}
\subsection*{Section 2}
\begin{multienumerate}[evenlist]
\mitemxxo{Yes}{$3x^2+x=-2$}
\mitemx{If $x=1$, the only solution is $y=3$.}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{Yes}{No}{No}
\mitemxxx{2}{5}{$-4$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\newsavebox{\diagonal}
\savebox{\diagonal}{\setlength{\unitlength}{.6pt}
\begin{picture}(70,70)(0,0)
\put(0,0){\framebox(70,70){}}
\put(35,5){\vector(0,1){60}}
\put(5,35){\vector(1,0){60}}
\put(10,10){\line(1,1){50}}
\end{picture}}
\mitemxx{\vskip0pt\usebox{\diagonal}}{\vskip0pt\usebox{\diagonal }}
\mitemx{Johnie should sell 3 red marbles, buy 2 white marbles, and keep the
rest.}
\mitemx{Sarah should buy 2 pounds of squash, 3 pounds of potatoes, and 4
pounds of fish.}
\end{multienumerate}
\subsection*{Answers to Odd Exercises} \subsection*{Chapter 2}
\subsection*{Section 1}
\begin{multienumerate}[oddlist]
\mitemxxx{Yes}{No}{No}
\mitemxxxx{3}{5}{2}{$-8$}
\mitemxxox{7}{$2x-3y=6$}{1}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxox{$x^2-3x+7=0$}{Yes}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{2}{5}{$-4$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{$x=1$}{$y=-7$}{$z=3$}
\mitemxxx{2}{5}{$-4$}
\end{multienumerate}
\end{multicols}

\end{document}

\noindent
\rule{\hsize}{2pt}
\begin{multienumerate}
\mitemxxxx{Not}{Linear}{Not}{Quadratic}
\mitemxxxo{Not}{Linear}{No; if $x=3$, then $y=-2$.}
\mitemxx{$(x_1,x_2)=(2+\frac{1}{3}t,t)$ or
$(s,3s-6)$}{$(x_1,x_2,x_3)=(2+\frac{5}{2}s-3t,s,t)$}
\mitemx{$(x_1,x_2,x_3,x_4)= (\frac{1}{4}+\frac{5}{4}s+\frac{3}{4}t-u,s,t,u)$
or $(s,t,u,\frac{1}{4}-s+\frac{5}{4}t+\frac{3}{4}u)$}
\mitemxxxx{$(2,-1,3)$}{None}{$(2,1,0,1)$}{$(0,0,0,0)$}
\end{multienumerate}
\noindent
\rule{\hsize}{1pt}