Is there a way to display a specific command and hide the rest

Question

I would like to use the same Latex source file for both my document and the accompanying slides.

When creating a document it's easy to hide the slide sections by doing this:

\newcommand{\slide}[1]{}

However, how do I do the inverse, i.e. How can I only generate the slides and hide the rest of the document if I want to print only my slides? Basically I want to say, if the content does not fall in a slide area, then don't show it.

Unfortunately I don't have a simple example to show, because I honestly don't know where to start.

Answer 1

One way to do this would be to use the environ package to save the \BODY of the document into a \savebox which saves the text passed to the \Slide macro in a list and output the list at the end. The following

\begin{document}
  abc
  \Slide{Slide 1 content}
  ghi
  \Slide{Slide 2 content}
  jkl
\end{document}

yields:

References:

• How keep a running list of strings and then process them one at a time

Code:

\documentclass{article}
\usepackage{environ}
%% --------------------------
\newsavebox{\DiscardedText}
\newcommand{\Slide}[1]{}
\newcommand{\SavedSlideText}{}
\newcommand\AddToSavedSlideText[1]{\xdef\SavedSlideText{\SavedSlideText#1\endgraf}}
\NewEnviron{GobbleExceptForSlide}{%
    \renewcommand{\Slide}[1]{\AddToSavedSlideText{##1}}%
    \savebox{\DiscardedText}{\BODY}%
    \SavedSlideText%
}%
\AtBeginDocument{\GobbleExceptForSlide}
\AtEndDocument{\endGobbleExceptForSlide}
%% --------------------------
\begin{document}
abc
\Slide{Slide 1 content}
ghi
\Slide{Slide 2 content}
jkl
\end{document}