Guide to LaTeX (4th Edition) (Tools and Techniques

198 Chapter 8. User Customizations
\renewenvironment{comment}
{\begin{sloppypar}\noindent\slshape Comment:
\begin{quote}\small\itshape}
{\stepcounter{com}\hspace*{\fill}(\arabic{com})\end{quote}
\end{sloppypar}}
With the \begin{sloppypar} command, the call to the environment
always starts a new paragraph in which no overfull line can occur upon
line breaking. If the comment number does not fit on the last line of
text, a new line begins with the number right justified because of the
command \hspace*{\fill}. Again the user should examine carefully
just what is inserted into the processing between the \begin{comment}
and the \end{comment}.
8.4.2 Environments with arguments
Passing arguments over to an environment is carried out exactly as for
commands. As an example, the comment environment will be modified so
that the name of the person making the comment is added after the word
Comment:, and this name will be an argument when the environment is
invoked.
\renewenvironment{comment}[1]
{\begin{sloppypar}\noindent\slshape Comment: #1
\begin{quote}\small\itshape}
{\stepcounter{com}\hspace*{\fill}(\arabic{com})%
\end{quote}\end{sloppypar}}
The text
\begin{comment}{Helmut Kopka} This is a modified ...
... environment argument \end{comment}
now produces
Comment: Helmut Kopka
This is a modified comment. Comments should be preceded by the
word Comment:, followed by the name of the commenter, with the text
of the comment being in a small, italic typeface, indented on both sides
from the main margins. Each comment receives a running comment
number at the lower right in round parentheses. The name of the
commenter is transferred as an environment argument. (2)
This example will now be modified once again by interchanging the
comment number and the name of the commenter. Placing the running
number after the word Comment: is no problem, for it is simply necessary
to insert those commands from {end def } at the location of the #1 dummy
argument. However, putting the symbol #1 where the comment number
used to be will produce an error message during the L AT E X processing since