Arguments in the destructor for an environment

Asked Jan 22 '22 at 21:17

Active Jan 22 '22 at 21:19

Viewed 15 times

The \newenvironment command allows the environment to take arguments:

\begin{article}
\newenvironment{preecho}[1]{#1}{}
\begin{document}
\begin{preecho}{Hi!}\end{preecho} % => Hi!
\end{document}

However, this argument cannot be accessed in the destructor:

\begin{article}
\newenvironment{postecho}[1]{}{#1} % => Illegal parameter number #1 in definition of \endpostecho.
\begin{document}
\begin{postecho}{Hi!}\end{postecho}
\end{document}

The error message makes it clear why this is happening. However:

Is this behaviour intentional?
Is there a \newenvironment-type command that makes the argument accessible in the destructor?

edited Jan 22 '22 at 21:19

asked Jan 22 '22 at 21:17

LSpice

1,448

1

Yes, it's the documented behavior. You can use \NewDocumentEnvironment instead, but the argument should be specified differently: \NewDocumentEnvironment{echo}{m}{}{#1} – egreg Jan 22 '22 at 21:19
@egreg, thanks! Which package provides that? – LSpice Jan 22 '22 at 21:20
1

No package, if you have LaTeX released on 2020-10-01 or later. – egreg Jan 22 '22 at 21:20
OK, thanks! So I should have said differently: where is the syntax documented? Also, since your comment clearly answers the question, would you be willing to post it as an answer, or is it better if I close the question? – LSpice Jan 22 '22 at 21:21
Answer to myself: this functionality is provided by xparse. – LSpice Nov 07 '22 at 00:59

Arguments in the destructor for an environment

0 Answers0