wrap LaTeX command in environment

Question

How can I wrap a LaTeX command in an environment? In essence, how can I turn \\somecommand{contents} into \\begin{somecommand} contents \\end{somecommand}? I have tried the obvi

Answer 1

It seems that now I can guess what is the question.

\newenvironment{very-important}{\startimportant}{}
\def\startimportant#1\end{\emph{#1}\end}

\begin{very-important}
Something
\end{very-important}

This solution works well. But IMHO it is bad idea to wrap all text in the environment. Why? There are two ways to do something with the text. For example, you want to change the font and use italic.

• The first method. \textit{sentence written in italics}
• The second method. {\it sentence written in italics\/}

What is the difference? The thing is that first method use the second one. \it macro changes the font and the brace } changes it back. \textit macro reads the full argument, changes the font and inserts the argument again: \textit is defined roughly as follows (not exactly).

\def\texit#1{{\it#1\/}}

The first method is always doing extra work. It reads the argument twice. Almost always, you can make changes and then you can everything back.

Eventually why do you use the environment? Use macros.

\veryimportant{
   Any thought
}

Answer 2

A Simpler way could be:

\newenvironment{somecommand}[0]{ \somecommand\bgroup } { \egroup }

Explanation: \bgroup works like { and \egroup works like }.

Answer 3

New environment somecommand defines the macro \somecommand. You can not use macro with the same name \somecommand inside.

Moreover you should write

\newenvironment{name}{openning command}{closing commands}

rather than

\newenvironment{somecommand}[0]{ \somecommand{ } { } }

You obviously have a problem with closing commands.

Answer 4

define command

\newcommnad{eqn}{1}{\begin{equation}#1\end{equation}}

will change

\eqn{x^2=y}

to

\begin{equation}
  x^2=y
\end{equation}

I think

Answer 5

This can be done with the environ package as follows:

\usepackage{environ}
...
\NewEnviron{very-important}{\emph{\BODY}}

\BODY contains the body of the environment, and environments may be nested. See the documentation for more details.