How to obtain a text surrounded with begin and end commands

Question

I want to obtain a text surrounded with begin and end commands, as the following.

\begincommand
Here any text is written.
\endcommand

\surroundedtext % this command is replaced with "Here any text is written."

Of course, the object is accomplished if I define \begincommand so that it takes an argument.

\def\begincommand#1{...}
\begincommand{Here any text is written.}

But, I don't want to use braces. Please let me know if you have the solution.

Answer 1

Assuming Plain TeX, you can define

\long\def\begincommand#1 \endcommand{...}

but this will force you to write

\begincommand
Text to be stored
\endcommand

with \endcommand on a line by itself or

\begincommand
Text to be stored \endcommand

with a space between the last word and \endcommand (but no empty line before \encommand). Alternatively, you can define

\long\def\begincommand#1\endcommand{...}

and then do something about the possible final space when \endcommand is on a line by itself. One should know the context, in order to give better advice.

If you're using LaTeX, this is not good programming style. If what you're looking for is an environment form for a "definition", then the environ package suggested by Leo Liu is handy, but poses some challenges for defining a command that uses the environment's body to be used subsequently.

\usepackage{environ}

\NewEnviron{command}{%
  \long\xdef\surroundedtext{%
    \unexpanded{<pre>}%
    \unexpanded\expandafter{\BODY}%
    \unexpanded{<post>}}%
  }

Thus the code

\begin{command}
Text to be stored
\end{command}

will be equivalent to

\newcommand{\surroundedtext}{<pre>Text to be stored<post>}

Add whatever you need in place of <pre> and <post>

Answer 2

You can see the implementation of LaTeX package environ, or just use this package.

Example:

\documentclass{article}
\usepackage{environ}
\NewEnviron{foo}{(\textbf{\BODY})}
\begin{document}
\begin{foo}
body
\end{foo}
\end{document}