I am using \begin{comment} hello world \end{comment} in order to comment out text in AucTex mode.

In general I am using different color for comments but when I use \begin{comment} [text] \end{comment}, the text in between them shows up as white (normal text color). I want it to be seen as in original comment color.

enter image description here

(setq LaTeX-item-indent 0)
(add-hook 'LaTeX-mode-hook 'turn-on-auto-fill)
(require 'tex)

(add-hook 'LaTeX-mode-hook (lambda ()
  (TeX-global-PDF-mode t)

General question: Is it possible to have different color in between a specific pattern?

Narrowed question: How can I have different color in auxtex for text for all kind of comments such as in between \begin{comment} and \end{comment}


This should be automatic if you have \usepackage{comment} or \usepackage{verbatim} in your preamble. At the time the question was asked, it was actually automatic only with \usepackage{comment}, but AUCTeX 12.3 onwards will do it for \usepackage{verbatim} as well.

If you've just added the \usepackage command, run TeX-normal-mode (C-c C-n) to tell AUCTeX to parse the preamble again.

More generally, if you define your own environments using a LaTeX package that AUCTeX doesn't know about, you can ask AUCTeX to parse the .sty file. See automatic customization. As a last resort, if your LaTeX code is too complex for AUCTeX to parse, write your own style support. You can look at style/comment.el in the AUCTeX distribution to see how the {comment} environment from the comment.sty package is declared: it adds an entries to font-latex-syntactic-keywords-extra, which is used to override syntax information to declare \begin{comment} as having comment-start syntax and \end{comment} as having comment-end syntax.

  • I was using it through verbatim : tex.stackexchange.com/a/17822/127048 . C-c C-n says Applying style hooks...done and does nothing – alper May 8 '20 at 13:13
  • Coloring does not also work for \iffalse ... \fi – alper May 8 '20 at 13:18
  • Ah if there is no space or tav before\begin{comment} it works but if there is space or tab it does not – alper May 8 '20 at 13:40
  • 3
    @alper Indeed AUCTeX's support code for the verbatim package doesn't color comment environments, only the support code for the comment package. This would be worth a feature request to AUCTeX. \iffalse…\fi is not a comment, it's a conditional construct, so there's no reason why it would be colored as a comment. Recognizing \begin{comment} and \end{comment} only at the start of a line is also a design choice in AUCTeX because \end{comment} from comment.sty has to be at the start of a line, unlike \end{comment} from verbatim.sty which is implemented slightly differently. – Gilles 'SO- stop being evil' May 8 '20 at 15:27
  • @Gilles'SO-stopbeingevil' - Fixed with this change. – Arash Esbati May 22 '20 at 19:27

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