Can I find out if I am in an environment?

Question

Is there a way to know if I am in an (specific) environment or not?

This MWE should clearify my question?

\documentclass{scrartcl}
\usepackage{xltxtra}
\usepackage{polyglossia}
\setdefaultlanguage[spelling=new]{german}

\newcommand{\myMacro}{%
    % if inside itemize
    in-itemize
    % else/default
    normal
}

%% Document %%
\begin{document}
\myMacro % „normal“

\begin{itemize}
    \item \myMacro % „in-itemize“
\end{itemize}
\end{document}

Answer 1

Here's a possible implementation of a stack saving the environments open at any time.

\documentclass{article}
\usepackage{etoolbox,xparse}

\makeatletter
\patchcmd{\begin}
  {\def\@currenvir}
  {\envstackpush{#1}\def\@currenvir}
  {}{}
\patchcmd{\end}
  {\@checkend}
  {\envstackpop\@checkend}
  {}{}
\makeatother

\ExplSyntaxOn
\seq_new:N \g_env_stack_seq
\NewDocumentCommand{\envstackpush}{m}
 {
  \seq_gpush:Nn \g_env_stack_seq { #1 }
 }
\NewDocumentCommand{\envstackpop}{}
 {
  \seq_gpop:NN \g_env_stack_seq \l_tmpa_tl
 }
\NewDocumentCommand{\inenvironment}{mmm}
 {
  \seq_if_in:NnTF \g_env_stack_seq { #1 } { #2 } { #3 }
 }
\NewDocumentCommand{\lastenvironment}{mmm}
 {
  \seq_get:NN \g_env_stack_seq \l_tmpa_tl
  \tl_set:Nn \l_tmpb_tl { #1 }
  \tl_if_eq:NNTF \l_tmpa_tl \l_tmpb_tl { #2 } { #3 }
 }
\ExplSyntaxOff

\newcommand{\myMacro}{%
  \inenvironment{itemize}{In itemize}{Not in itemize}%
}
\newcommand{\myMacroLast}{%
  \lastenvironment{itemize}{In itemize}{Not in itemize}%
}

\begin{document}

\begin{itemize}
\item A
\item B
  \begin{enumerate}
  \item \myMacro
  \item \myMacroLast
  \end{enumerate}
\item \myMacro
\end{itemize}

\begin{enumerate}
\item A
\item B
  \begin{itemize}
  \item \myMacro
  \item \myMacroLast
  \end{itemize}
\item \myMacro
\end{enumerate}

\end{document}