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I would like to create a command \comment{} which would not compile anything inside of { }.

Why would I not use % or \begin{comment} bla bla \end{comment} from the \usepackage{comment}? Because I want to put some text inside brackets and comment it.

The reason I want to do this is because I have a lot of text in red using \textcolor{red}{bla bla} and I would like to redefine \textcolor{red} so that I can delete everything in red from my document (note that I have a lot of parts in red...).

In a nutshell, my current code

x=x+1 \\
\textcolor{red}{
    I don't want to see this
}

produces this

enter image description here

Instead I would like it to produce this

enter image description here

without having to comment manually every part with \textcolor{red}. I would instead like to redefine this command so that it would comment the text in red.

Note: I want the red text not to be compiled and not to appear invisible, creating blank spaces.

Babado
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  • Have a look at the todonotes pacakge. That can do waht you want, plus a lot more. – Peter Grill Oct 19 '21 at 16:23
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    if that's your only use of colour then \renewcommand\textcolor[2]{\ignorespaces} otherwise you need to include a test for red – David Carlisle Oct 19 '21 at 16:30
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    Search and replace all \textcolor{red} by \comment. Then you only need \newcommand \comment[1]{\textcolor{red}{#1}} to show the comments in red or \newcommand \comment[1]{\ignorespaces}} to hide the comments. – Fran Oct 19 '21 at 16:49
  • Do you want the invisible part to still take up space in the resulting pdf? Or should it not happen at all? – Teepeemm Oct 19 '21 at 18:21
  • @Teepeemm, it shouldn't happen. – Babado Oct 20 '21 at 07:52

1 Answers1

1

Using the command \suppress from Selectively suppress generation of typeset output to redefine \textcolor

Original document x

Redefining \textcolor

x

\documentclass[12pt,a4paper]{article}

\usepackage{xcolor}
\usepackage{ifthen}


\let\oldtextcolor\textcolor 
\renewcommand{\textcolor}[2]{% <<<<<<<<<<<<<<<<<<<<<<
    \ifthenelse{\equal{red}{#1}}
    {\suppress#2\endsuppress}
    {\oldtextcolor{#1}{#2}}%
}


%% From https://tex.stackexchange.com/a/97360/161015
\makeatletter

\font\dummyft@=dummy \relax
\def\suppress{%
    \begingroup\par
    \parskip\z@
    \offinterlineskip
    \baselineskip=\z@skip
    \lineskip=\z@skip
    \lineskiplimit=\maxdimen
    \dummyft@
    \count@\sixt@@n
    \loop\ifnum\count@ >\z@
    \advance\count@\m@ne
    \textfont\count@\dummyft@
    \scriptfont\count@\dummyft@
    \scriptscriptfont\count@\dummyft@
    \repeat
    \let\selectfont\relax
    \let\mathversion@gobble
    \let\getanddefine@fonts@gobbletwo
    \tracinglostchars\z@
    \frenchspacing
    \hbadness@M}
\def\endsuppress{\par\endgroup}
\makeatother


\begin{document}


As any dedicated reader can clearly see, the Ideal of practical reason is a
representation of, as far as I know, the things in themselves; as I have shown
elsewhere, the phenomena should only be used as a canon for our under-
standing.


x=x+1


\noindent \textcolor{red}{I don't want to see this \ I don't want to see this  \ I  don't want to see this.}


Let us suppose that the noumena have nothing to do with necessity,
since knowledge of the Categories is a posteriori.


{\color{red} But I want to see this.}


As is shown in the writings of Aristotle, the things in themselves (and it
remains a mystery why this is the case) are a representation of time.


\textcolor{green}{And also to see this.}


Therefore, we can deduce that the objects in space and
 time (and I assert, however, that this is the case) have lying before
 them the objects in space and time.


\end{document}

From the quoted link

However rules, radical bars, fraction bars and some other things (mostly math) can escape.

Simon Dispa
  • 39,141
  • Interesting solution, but then the text that is not visible creates "blank space" in the document. Not sure if this is desired. – Peter Grill Oct 19 '21 at 20:04
  • @Peter Grill I know, but literally reproduced the OP posted output :). I updated the answer for a more useful solution. – Simon Dispa Oct 19 '21 at 22:32
  • @SimonDispa thank you for your answer. Maybe I wasn't clear enough when I first posted the question, but I don't want the red text to be compiled. Putting the text invisible and creating blank spaces is not ideal for me. – Babado Oct 20 '21 at 07:58
  • @Babado How or where do you see blank spaces? The red text is not typeset. In the figure there are not blank lines. – Simon Dispa Oct 20 '21 at 15:09
  • For example, if I have $\textcolor{red}{\colorbox{black}{I don't want to see this}}$, I don't see the text but I see the black background. – Babado Oct 21 '21 at 05:44