2

I'm trying to create a horizontal white space in my multicolumn environment every time I start a new subsection.

It stops people from having to trawl their eyes up and down the page between different content, splitting the page in a more readable fashion.

However, I keep getting the following error:

        ! Missing \endcsname inserted.
       <to be read again>
       \let
       l.83 \renewenvironment{\subsection}
       {\end{multicols}}{\start{multicols}{2}}
       The control sequence marked <to be read again> should
       not appear between \csname and \endcsname.

Minimal example:

\documentclass[11pt]{article}
\usepackage{multicol}


%\let\origsubsection\subsection
\renewcommand{\subsection}{\end{multicols}\subsection\start{multicols}{2}}

\begin{document}

\section{Something here}
Filler text1

\begin{multicols}{2}

\subsection{This is a test1}  %\endMulti startsub  \beginMulti
Filler text2
\subsection{This is a test2}  %\endMulti startsub  \beginMulti
Filler text3

\end{multicols}
\end{document}
jub0bs
  • 58,916
tetris11
  • 187
  • 7

3 Answers3

7

You had defined \subsection in terms of itself which would have been an infinite loop, but you also used a command \start that is undefined. You intended something more like this:

\documentclass[11pt]{article}
\usepackage{multicol}


\let\origsubsection\subsection
\renewcommand{\subsection}[1]{\end{multicols}\origsubsection{#1}\begin{multicols}{2}}

\begin{document}

\section{Something here}
Filler text1

\begin{multicols}{2}

\subsection{This is a test1}  %\endMulti startsub  \beginMulti
Filler text2
\subsection{This is a test2}  %\endMulti startsub  \beginMulti
Filler text3

\end{multicols}
\end{document}
David Carlisle
  • 757,742
2

Idea is the same as in the other answer, however, the support for the starred varian and the optional argument was added:

\makeatletter
\let\subsection@old\subsection
\def\subsection@pre{\end{multicols}}
\def\subsection@post{\begin{multicols}{2}}
\newcommand\subsection{\@ifnextchar*\subsection@star\subsection@nostar}
\def\subsection@star*#1{\subsection@pre\old@subsection*{#1}\subsection@post}
\def\subsection@nostar{\@ifnextchar[\subsection@br\subsection@nobr}
\def\subsection@br[#1]#2{\subsection@pre\old@subsection[#1]{#2}\subsection@post}
\def\subsection@nobr#1{\subsection@pre\old@subsection{#1}\subsection@post}
\makeatother

Sorry for the (a bit) cryptic code, I don't like using \@dblarg and \@ifstar

Community
  • 1
yo'
  • 51,322
1

enter image description here

Is this what you wanted?! I hope so. If you also want to change the spacing before section and subsection check this answer.

I assumed that you have an article (and don't have any chapters). I also assumed that you want the entire stuff to be twocolumn, and stop it at every section and subsection command.

Instead of the \begin{multicols} and \end{multicols} notation I used the macro calls \multicols and \endmulticols.

\documentclass[11pt]{article}

\usepackage{lipsum} % demo only

\usepackage{multicol}

\AtBeginDocument{\begin{multicols}{2}}
\AtEndDocument{\end{multicols}}

\makeatletter
\let\section@orig\section
\let\subsection@orig\subsection
\renewcommand\section[1]{\endmulticols\section@orig{#1}\multicols{2}}
\renewcommand\subsection[1]{\endmulticols\subsection@orig{#1}\multicols{2}}
\makeatother

\begin{document}

\show\section
\show\subsection

\section{Section}

\lipsum[1]

\subsection{Subsection}

\lipsum[2]

\subsection{Subsection}

\lipsum[3]

\section{Section}

\lipsum[4]

\subsection{Subsection}

\lipsum[5]

\subsection{Subsection}

\lipsum[6]

\end{document}

Note: lipsum is only present for the demo text.

I've also tried to use xpatch, but instead of a solution I've created a problem... here's a partial code. I don't know how to fix the issue... \protect doesn't seem to solve anything other than removing the errors... Related topic: What is the difference between Fragile and Robust commands?

\documentclass[11pt]{article}

\usepackage{lipsum} % demo only

\usepackage{multicol}
\usepackage{xpatch}

\AtBeginDocument{\begin{multicols}{2}}
\AtEndDocument{\end{multicols}}

\xpretocmd{\section}{\endmulticols}{}{}
\xapptocmd{\section}{\protect\multicols{2}}{}{}
\xpretocmd{\subsection}{\endmulticols}{}{}
\xapptocmd{\subsection}{\protect\multicols{2}}{}{}

\begin{document}

\section{Section}

\lipsum[1]

\subsection{Subsection}

\lipsum[2]

\subsection{Subsection}

\lipsum[3]

\section{Section}

\lipsum[4]

\subsection{Subsection}

\lipsum[5]

\subsection{Subsection}

\lipsum[6]

\end{document}
Community
  • 1
masu
  • 6,571
  • you've loaded xpatch but not used it, but redefined in the classic \let\subsection@orig\subsection manner instead (using xpatch might have been an interesting alternative to the other annwers) \protect isn't likely to be needed there (you are not likely to use \subsection in a moving argument.) – David Carlisle Dec 10 '13 at 19:27
  • @DavidCarlisle I've tried that, that's why xpatch remained in the code... but \xapptocmd didn't seem to work easily (without messing with the internals of the \section definition). It messed the titles, and need more tweeking around than this. So this seemed to be more appropriate. – masu Dec 10 '13 at 19:39
  • This is very nice though, exactly what I wanted. @masu - Could you expand a bit on how protect works? – tetris11 Dec 10 '13 at 19:43
  • @tetris11 I've added a reference instead – masu Dec 10 '13 at 19:50
  • as David mentioned, you don't really need the protect there... – masu Dec 10 '13 at 20:08
  • @DavidCarlisle I've added the xpatch alternative I've created (but didn't work). Can you suggest anything? – masu Dec 10 '13 at 20:15