\documentclass{article}
\usepackage{mykeyval}
\begin{document}

Simple KV no options: \KVsimple

Simple KV with options: \KVsimple[width=100, height=200]

Complex KV no options: \KVcomplex

Complex KV with options: \KVcomplex[width=100, height=200]

Filenames \KVsimple[path=a_dir/~foo.bar]

Filenames \textbf{\KVsimple[path=a_dir/~foo.bar]}

KV Environment no options:
\begin{KVenv}
Inside the environment.
\end{KVenv}
After the environment.

KV Environment with options:
\begin{KVenv}[width=100, height=200]
Inside the environment.
\end{KVenv}
After the environment.


KV Environment with structure no options:
\begin{KVstruct}
Inside the environment.
\end{KVstruct}
After the environment.

KV Environment with structure with options:
\begin{KVstruct}[width=100, height=200]
Inside the environment.
\end{KVstruct}
After the environment.

KV automatic conversion to structure
\KVauto{width=100, height=200}
\end{document}
