Define a `\newenvironment` that stores its content in a token register or in a macro

Question

In the code below I want to define a new environment that stores its contents in order to use it later several times with different formats

\documentclass{article}
  \newtoks\environmentcontents
   \newenvironment{myenv}{%
      %\environmentcontents=\bgroup
      }
     {%
      %\egroup
      }

\begin{document}
   \begin{myenv}
      some tokens here
    \end {myenv}


  % {\tiny \environmentcontents}

  Some text in between the same content

 % {\Large \environmentcontents}

\end{document}

You lose the line breaks; is really an environment necessary? — egreg, Jul 27 '19 at 17:24
@egreg. I don't know if an environment is necessary but the goal is to modify an existing one — Hafid Boukhoulda, Jul 27 '19 at 17:30
@PhelypeOleinik What is the b argument type in xparse? Do you mean the d argument type? — Hafid Boukhoulda, Jul 27 '19 at 20:57
@HafidBoukhoulda No, b :-) It's a new feature implemented earlier this year. You can do \usepackage{xparse} then, for instance, \NewDocumentEnvironment{myenv}{+b}{The environment contains (#1)}{}, or \NewDocumentEnvironment{myenv}{+b}{\gdef\environmentcontents{#1}}{}. — Phelype Oleinik, Jul 27 '19 at 21:38
b collects the body of the environment and lets you use it like a normal argument. +b makes the argument \long, i.e. also permits the use of paragraph breaks in the argument. — siracusa, Jul 28 '19 at 01:32

score 1 · Accepted Answer · answered Apr 21 '20 at 15:45

I am not exactly sure why you want tokens, rather than, for example, just \long\defing the desired content. However, the tokcycle package is for collecting and operating on tokens. In this case, the operation is merely passing through the tokens unchanged. So as long as you haven't directed the package to process the tokens in a different fashion, the myenv pseudo-environment will collect your tokens in the token register \cytoks. The last thing I do in the MWE is to regurgitate the detokenized \cytoks, so that you can verify that, yes indeed, it has collected the original (unexpanded) tokens.

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage{lmodern}
\usepackage{tokcycle}
\def\myenv{\begingroup\let\endmyenv\endtokcycraw
  \aftertokcycle{\expandafter\endgroup\expandafter\tcenvscope
  \expandafter{\the\cytoks}}\tokcycrawxpress}
\begin{document}
   \myenv
      some tokens \textit{here}, \today
    \endmyenv

   {\tiny \the\cytoks}

  Some text in between the same content

  {\Large \the\cytoks}

\detokenize\expandafter{\the\cytoks}
\end{document}

Define a `\newenvironment` that stores its content in a token register or in a macro

1 Answers1