environmentsverbatim
I would like to create a new environment that would automate the following code:
\setbox0=\hbox{\begin{minipage}{5.8in}
\color{black}
\begin{verbatim}
<Some verbatim text here>
\end{verbatim}
\end{minipage}}
\fcolorbox{blue!30}{gray!7}{\box0}
I'm pretty new to Latex, so I apologize if this question is not clear or if there is some obvious mistake. I also want to say that this site is fantastic and extremely helpful for new Latex users like myself.
In this particular case the problem is a typical one: You can't pass verbatim content as an argument to another macro. This is indeed the case with using environ, since content is accumulated in the macro \BODY for processing later.
From the looks of your minimal example, it seems like you're after printing verbatim content using a specific colour (say red). For this I'd suggest defining a new verbatim environment with this specific quality/attribute. As such, fancyvrb can come in handy. Here's a MWE that illustrates this concept (taken, virtually verbatim, from the fancyvrb documentation (section 4.1.3 Customization of formatting, p 5 and 4.2.4 Personalized environments, p 18)):
\documentclass{article}
\usepackage{fancyvrb,xcolor}% http://ctan.org/pkg/{fancyvrb,xcolor}
\DefineVerbatimEnvironment%
{MyVerbatim}{Verbatim}
{formatcom=\color{red}}
\begin{document}
\begin{MyVerbatim}
First verbatim line.
Second verbatim line.
\end{MyVerbatim}
\end{document}
The main problem with using your definition of myverbatim can be defined in terms of a combination of scope and macro replacement. That is, something that starts with
\begin{<some-env>}
is expected to end with
\end{<some-env>}
If it doesn't, there's a problem, since the scope is not clearly defined. In your case, you start it with
\begin{myverbatim}
which is internally replaced with (removing the font change to \tiny for now)
\begin{verbatim}
Now, since you're in the verbatim environment (that is, a successful call was made to \begin{verbatim}), LaTeX starts gobbling up contents and printing them as-is until it arrives at a single line of code that resembles
\end{verbatim}
That's just how the verbatim environment works. It it looking for the stopping point. However, this never happens since the replacement of \end{myverbatim} (in your code) to \end{verbatim} (as per your definition) never occurs within the verbatim environment; verbatim doesn't perform the replacement of macros with their definitions. As such, TeX just keeps on scanning, producing what is considered a "Runaway argument" error.
Taking the above into account, a broad view on the replacement leaves your MWE to resemble (I've added a comment):
\documentclass{article}
\newenvironment{myverbatim}{\tiny\begin{verbatim}}{\end{verbatim}}
\begin{document}
\tiny\begin{verbatim}% Replacement text for \begin{myverbatim}
test
\end{myverbatim}% No replacement since you're in the verbatim environment
\end{document}
Clearly the above doesn't start and end with the same environment.
If you want to have more flexibility with verbatim, use the verbatim package which allows you to do the following:
\documentclass{article}
\usepackage{verbatim}% http://ctan.org/pkg/verbatim
\newenvironment{myverbatim}%
{\endgraf\tiny\verbatim}%
{\endverbatim}
\begin{document}
Some text before.
\begin{myverbatim}
test
test
\end{myverbatim}
Some text after.
\end{document}
The verbatim package is a means to obtain your desired solution, just like fancyvrb and listings would be. Of course, a more rudimentary implementation (specific to your case) would be to merely change the font used by verbatim - stored in the macro \verbatim@font:
\makeatletter
\renewcommand{\verbatim@font}{\tiny\ttfamily}
\makeatother
Sure you can just precede the verbatim environment with \tiny and it will work just as well, but \verbatim@font is called within the verbatim environment, and therefore is constrained to only function there, not outside of it.
Best Answer
Adapting from code in this answer
Here's a version with additional vertical spaces. The interaction with
Verbatimmakes it somewhat difficult to guess at the right proportions, just experiment.For fancier boxes, you can have a look at
tcolorbox