# [texhax] meddling with the comment environment in latex, article class

Eduardo M KALINOWSKI ekalin at gmail.com
Tue Nov 20 23:54:16 CET 2007

On Nov 20, 2007 7:55 PM, Micha Hofri <hofri at wpi.edu> wrote:
>
> I write many homework assignments for my students that I post twice, The
> second time with solutions; each problem is followed by its solution.
>
> Naturally I want to use the same file for the two postings. My current
> method: surround the solutions by \begin{comment}...\end{comment} and use
> a parameter that gets a value 0 (no solutions) or 1 (with solutions),
> When it is 1 an \ifthenelse kicks in that activates a \renewenvironment,
> which replaces the comment delimiters by a text like "solution:"
>
> Thus when I need to post solutions, the only editing is to change one
> \newcommand argument from 0 to 1. This works well, but I "lose" the
> normal use of the comment environment, which I would like to keep.
>
> The same parameter is also used to drive changes in headers and markings,
> so I would like to keep using it.  I thought of a new environment, say
> solution, in which to keep the solutions, and then skip them when my
> parameter is 0, but I cannot do it with the comment environment (the
> \end{solution} is not caught..). there is certainly an obvious solution
> that evades me.

See the documentation for the comment package. You can achieve what
you currently have in an easier way with \includecomment and
\excludecomment.