Custom environment numbering dependent on documentclass

Question

Expanding on the answer here. I have a custom environment defined that automatically prepends the chapter number to its own counter. Obviously this only works for those documentclasses that define a chapter number and produces an error with article etc.

Is there a way to build an if/then statement into the environment itself that prefixes the chapter number only when chapternumber is defined and skips the prefix when not?

%\documentclass{article}
\documentclass{report}

\usepackage{xkeyval}
\usepackage{noindentafter}

\makeatletter
\define@boolkey{fam}[myenv@]{title}[true]{}
\define@boolkey{fam}[myenv@]{notitle}[true]{\ifmyenv@notitle\myenv@titlefalse\else\myenv@titletrue\fi}
\define@cmdkey{fam}[myenv@]{label}[\relax]{}
\define@cmdkey{fam}[myenv@]{repeat}[\relax]{}
\newcounter{myenvcnt}[chapter]%
\renewcommand{\themyenvcnt}{\thechapter.\arabic{myenvcnt}}
\newenvironment{myenv}[1][]{%
  \setkeys{fam}{title,label,repeat,#1}%
  \ifmyenv@title%
    \par%
    \expandafter\ifx\myenv@repeat\relax
      \refstepcounter{myenvcnt}%
      \expandafter\ifx\myenv@label\relax\else\label{\myenv@label}\fi
    \else
      \renewcommand{\themyenvcnt}{\ref{\myenv@repeat}}%
    \fi
    \subsubsection*{\textit{myenv\ \themyenvcnt}}% 
    \par\nobreak%
  \else% = if no title
    \par\addvspace{\bigskipamount}%
  \fi
  \edef\@currentlabel{\themyenvcnt}%
}{\par\addvspace{\bigskipamount}%
}
\NoIndentAfterEnv{myenv}
\appto\@noindent@newenv@hook{\par}{}{}
\makeatother


\begin{document}

\begin{myenv}
My environment.
\end{myenv}

\myenv{Test}

\end{document}

Any help how to do this or where to start would be much appreciated.

try \@ifundefined{cmd}{then}{else} – nox Jul 10 '18 at 00:28 — nox, Jul 10 '18 at 00:28
@nox I had no idea it was that easy :) – jan Jul 10 '18 at 00:50 — jan, Jul 10 '18 at 00:50

score 1 · Accepted Answer · answered Jul 10 '18 at 00:43

You could use the following:

%\documentclass{article}
\documentclass{report}

\usepackage{xkeyval}
\usepackage{noindentafter}

\makeatletter
\define@boolkey{fam}[myenv@]{title}[true]{}
\define@boolkey{fam}[myenv@]{notitle}[true]{\ifmyenv@notitle\myenv@titlefalse\else\myenv@titletrue\fi}
\define@cmdkey{fam}[myenv@]{label}[\relax]{}
\define@cmdkey{fam}[myenv@]{repeat}[\relax]{}


\newcounter{myenvcnt}
\@ifundefined{chapter}{}{%
\@addtoreset{myenvcnt}{chapter}
\renewcommand{\themyenvcnt}{\thechapter.\arabic{myenvcnt}}}

\newenvironment{myenv}[1][]{%
  \setkeys{fam}{title,label,repeat,#1}%
  \ifmyenv@title%
    \par%
    \expandafter\ifx\myenv@repeat\relax
      \refstepcounter{myenvcnt}%
      \expandafter\ifx\myenv@label\relax\else\label{\myenv@label}\fi
    \else
      \renewcommand{\themyenvcnt}{\ref{\myenv@repeat}}%
    \fi
    \subsubsection*{\textit{myenv\ \themyenvcnt}}% 
    \par\nobreak%
  \else% = if no title
    \par\addvspace{\bigskipamount}%
  \fi
  \edef\@currentlabel{\themyenvcnt}%
}{\par\addvspace{\bigskipamount}%
}
\NoIndentAfterEnv{myenv}
\appto\@noindent@newenv@hook{\par}{}{}
\makeatother


\begin{document}

\begin{myenv}
My environment.
\end{myenv}

\myenv{Test}

\end{document}

Custom environment numbering dependent on documentclass

1 Answers1