\documentclass{article}
\usepackage{xsimverb,listings,xcolor}

\lstdefinestyle{mystyle}{
  language = [AlLaTeX]TeX ,
  basicstyle = \ttfamily ,
  columns = fullflexible ,
  commentstyle = \color{gray!70} ,
  keywordstyle = \color{red!70!black}
}

\makeatletter
\NewDocumentEnvironment{example}{o}
  {%
    \XSIMgobblechars{2}%
    \XSIMsetfilebegin{\@percentchar\space file `\jobname.tmp'}%
    \XSIMsetfileend{\@percentchar\space bye bye}%
    \IfNoValueTF{#1}
      {\XSIMfilewritestart*{\jobname.tmp}}
      {\XSIMfilewritestart{\jobname.tmp}}%
  }
  {%
    \XSIMfilewritestop
    \lstinputlisting[style=mystyle]{\jobname.tmp}%
    \input{\jobname.tmp}
  }

\NewDocumentEnvironment{code}{o}
  {%
    \XSIMgobblechars{2}%
    \IfNoValueTF{#1}
      {\XSIMfilewritestart*{\jobname.tmp}}
      {\XSIMfilewritestart{\jobname.tmp}}%
  }
  {%
    \XSIMfilewritestop
    \lstinputlisting[style=mystyle]{\jobname.tmp}%
  }
\makeatother

\begin{document}

\begin{example}
  bla bla \LaTeX
\end{example}

\bigskip

\begin{code}
  blubber \LaTeX
\end{code}

\end{document}
