Disable/Enable Comment Block With Macro?

Question

Is there a way to make a macro within a LaTeX document, which would enable or disable a comment block? I do this sort of thing in C and C++, but am not sure about LaTeX.

For example, near the top of the document I would like some sort of line(s) which have a 0 or a 1. I would change between the 0 and 1 at my discretion. If 0, then my later portion would look like:

\begin{comment}
\begin{figure}[ht]
    \centering
    \includegraphics[width=0.5\textwidth]{BLARG.jpg}
    \caption{\label{fig:}HONK.}
\end{figure}
\FloatBarrier
\end{comment}

But if the macro number were 1, it would disable the comment function, so it would effectively leave the document with:

\begin{figure}[ht]
    \centering
    \includegraphics[width=0.5\textwidth]{BLARG.jpg}
    \caption{\label{fig:}HONK.}
\end{figure}
\FloatBarrier

Is this possible?

Answer 1

Yes... if you write your own comment environment using environ:

\documentclass{article}

\usepackage{environ,graphicx}

\NewEnviron{comment}{%
  \ifnum\keepcomment=1
  \else
    \BODY
  \fi
}

%\newcommand{\keepcomment}{1}% Keep comment
\newcommand{\keepcomment}{0}% Remove comment

\begin{document}

Some text before the figure.

\begin{comment}
  \begin{figure}[ht]
    \centering
    \includegraphics[width=0.5\textwidth]{example-image}
    \caption{\label{fig:example}Example image.}
  \end{figure}
\end{comment}

Some text after the figure.

\end{document}

---

If you're using the comment package you can do something similar:

\usepackage{comment}

%\newcommand{\keepcomment}{1}% Keep comment
\newcommand{\keepcomment}{0}% Remove comment

\AtBeginDocument{\ifnum\keepcomment=1
  \excludecomment{comment}
\else
  \includecomment{comment}
\fi}