How to create a dummy generic environment replacement?

Question

I am trying to create a debug mode where I can comment out most things on the document. For now I was able to replace commands like \currenttime from datetime package with \def\currenttime{Current Time}.

But when I tried to create a generic replacement for a environment as longtable I could not create successfully a dummy environment. Doing:

\documentclass[10pt,a5paper,twoside]{memoir}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage[brazil]{babel}
\usepackage[showframe,pass]{geometry}

\newif\ifdebug
\debugtrue
% \debugfalse

\ifdebug
    \def\hline{hline}
    \def\RaggedRight{RaggedRight}

    \newenvironment{longtable}[2]
        {longtable environment}
        {replacement for debug mode}
\else\fi

\begin{document}
\begin{longtable}[!ht]{ | >{\RaggedRight}p{3cm} | p{6cm} | }

        \hline
        Cor                          & Branco  \\ \hline
        Formato do papel             & A5      \\ \hline

\end{longtable}
\end{document}

Throw these errors:

! Misplaced alignment tab character &.
l.93         Cor                          &
                                            Branco  \\ \hline
I can't figure out why you would want to use a tab mark
here. If you just want an ampersand, the remedy is
simple: Just type `I\&' now. But if some right brace
up above has ended a previous alignment prematurely,
you're probably due for more error messages, and you
might try typing `S' now just to see what is salvageable.

! Misplaced alignment tab character &.
l.94         Formato do papel             &
                                            A5      \\ \hline
I can't figure out why you would want to use a tab mark
here. If you just want an ampersand, the remedy is
simple: Just type `I\&' now. But if some right brace
up above has ended a previous alignment prematurely,
you're probably due for more error messages, and you
might try typing `S' now just to see what is salvageable.

For now I think the dummy environment could just output its contents as plain text or not display anything at all. Can it be fixed for replacing any environment, independent of the number of parameters or its contents?

---

Related:

1. Environment with a dummy parameter
2. Defining an Environment that Takes an Argument
3. Creating a new environment with one optional argument
4. How to create a "delay expansion" environment?
5. Is there a generic dummy command?

Answer 1

If you want something that works "regardless of the content" you will need some type of verbatim environment:

\documentclass[10pt,a5paper,twoside]{memoir}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage[brazil]{babel}
\usepackage[showframe,pass]{geometry}
\usepackage{verbatim}
\newif\ifdebug
\debugtrue
% \debugfalse

\ifdebug
    \def\hline{hline}
    \def\RaggedRight{RaggedRight}

    \newenvironment{longtable}[2][]
        {longtable environment\par\verbatim}
        {\endverbatim \endgraf replacement for debug mode}
\else\fi

\begin{document}
\begin{longtable}[!ht]{ | >{\RaggedRight}p{3cm} | p{6cm} | }

        \hline
        Cor                          & Branco  \\ \hline
        Formato do papel             & A5      \\ \hline

\end{longtable}
\end{document}

[![enter image description here][1]][1]

If the content should disappear check the comment package.

Answer 2

You should change the cat code of & to a "other" (12). If you don't do that & will be an alignment character which LaTeX cannot treat outside of tables.

Side note: You should not change it to "letter" (11) as then LaTeX code like \mycell& will give an error (the & will be part of the macro name).

\documentclass[10pt,a5paper,twoside]{memoir}

\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}

\usepackage[brazil]{babel}
\usepackage[showframe,pass]{geometry}

\newif\ifdebug
\debugtrue
%\debugfalse

\ifdebug
    \def\hline{hline}
    \def\RaggedRight{RaggedRight}

    \newenvironment{longtable}[2][]
        {\catcode`&=12 longtable environment}
        {\catcode`&=4 replacement for debug mode}
\else\fi

\begin{document}
\begin{longtable}[!ht]{ | >{\RaggedRight}p{3cm} | p{6cm} | }
        \hline
        Cor                          & Branco  \\ \hline
        Formato do papel             & A5      \\ \hline
\end{longtable}
\end{document}