General ⇒ Example Environment, (a la 'lshort')

[calder]

What would it take to create a minimal Example environment like the one used in lshort? Basically,

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\begin{example}
LaTeX code
\end{example}

Generates the verbatim "LaTeX code" to the left and a box with the compiled version of the code to the right. I've tried looking at 'lshort.sty' but it includes so much other stuff that it's hard to understand what's going on. A bare minimum example that simply generates verbatim as well as interpreted code chunks would be very welcome.

Thanks in advance,
-Calder Coalson

[localghost]

I guess the showexpl package is that what you need in this case.


Best regards and welcome to the board
Thorsten¹

[calder]

Hrm, thanks for the help, but unfortunately this isn't quite what I'm looking for. The two problems with it may be very minor, but I've spent nearly 4 hours trying to solve them already and failed, so here they are:
1) There is no line-wrapping for the verbatim code, so the line just keeps going and going and going until it goes right off the page.
2) The font's bad and there's no simple way of changing that. Minor issue, but I really like the default verbatim font style. Much more suitable for code.

[gmedina]

Both issues can be easily solved taking into account that you can use all the power of the listings package (package documentation). Take a look at the following simple example:

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\documentclass{article}
\usepackage{showexpl}
\usepackage{amsmath}
\usepackage{xcolor}

\lstset{%
    basicstyle=\ttfamily\small,
    commentstyle=\itshape\ttfamily\small,
    showspaces=false,
    showstringspaces=false,
    breaklines=true,
    backgroundcolor=\color{lightgray},
    breakautoindent=true,
    captionpos=t
}

\begin{document}

\begin{LTXexample}[wide,width=.75,preset=\footnotesize,rframe=single]
\documentclass[a4paper,twoside]{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}\label{eq:barwq}
  \begin{split}
    H_c&=\frac{1}{2n}\sum^n_{l=0}(1)^{l}(n{l})^{p2}
    \sum_{l _1+\dots+ l _p=l}\prod^p_{i=1}\binom{n_i}{l _i}\\ &\quad
    \cdot[(nl)(n_il_i)]^{n_il_i}\cdot\Bigl[(nl)^2\sum^p_{j=1}(n_il_i)^2\Bigr].
  \end{split}
\end{equation}

\end{document}
\end{LTXexample}

\end{document}

A good starting point would be to have a look a the file showexpl-test.tex that comes in the showexpl.zip file.

[calder]

Thanks a ton gmedina and localghost! One last problem, and then I promise to stop bugging youguys. How can I include this in a macro? Do I need to define a custom .sty file?

[gmedina]

I don't fully understand your question. What exactly do you want to include in a macro? Please try to describe exactly what you expect to achieve.

[calder]

It's simply a matter of good form, but it would be nicer to have a command like this:

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\newcommand{example}[1]{
\begin{LTXexample}[bunch-o'-options]
  #1
\end{LTXexample}
}

and simply have to write:

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\example{blablabla}

Than to have to write:

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\begin{LTXexample}[bunch-o'-options]
  #1
\end{LTXexample}

every time.

Now, this isn't a big issue, unless I decided to globally change one of the options at a later date. Besides, it makes the code cleaner. If this isn't easily possible, I'll give up and just do it the sloppy way, but if it's within my capabilities to do, I'd feel dumb not to.


http://xkcd.com/292/

Thanks again for all the help and humoring my idiosyncrasies.

[phi]

This is no problem, the only thing is that you cannot use a command (because the code has to be written into a file without changes, which isn't easy if it was grabbed as a command argument), but it should be possible to use a custom environment:

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\newenvironment{example}{\LTXexample[options]}{\endLTXexample}

[gmedina]

...but it should be possible to use a custom environment:

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\newenvironment{example}{\LTXexample[options]}{\endLTXexample}

No. That will not work.

[phi]

ok, but still no problem:

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\makeatletter
\def\my@expl@ptions{wide,width=.75,preset=\footnotesize,rframe=single}
\lstnewenvironment{example}{%
	\begingroup
	\advance\c@ltxexample\@ne
	\advance\c@lstlisting\@ne
	\edef\x{%
		\noexpand\lstset{\unexpanded\expandafter{\SX@explpreset},\unexpanded\expandafter{\my@expl@ptions}}%
		\endgroup
		\def\noexpand\SX@codefile{\SX@codefile}%
		\def\noexpand\SX@graphicname{\SX@graphicname}%
		\def\noexpand\SX@graphicparam{\SX@graphicparam}%
	}%
	\x
	\xdef\SX@@explpreset{%
		\unexpanded\expandafter{\my@expl@ptions},%
		codefile=\SX@codefile,%
		graphic={[\SX@graphicparam]{\SX@graphicname}}%
	}%
	\setbox\@tempboxa=\hbox\bgroup
	\lst@BeginWriteFile{\SX@codefile}%
}{%
  \lst@EndWriteFile\egroup
  \SX@put@code@result
}
\makeatother