I would like to make a command in LaTeX that prints something if it is preceded by a certain character and something else if it is preceded by any other character.

With `\@ifnextchar` I can base the output on the character *after* the command:

```
\documentclass{article}

\makeatletter
\newcommand\mycommand{\@ifnextchar h{I see an h\ }{I don't see an h\ }}
\makeatother

\begin{document}

\mycommand h %output: I see an h h
\mycommand n %output: I don't see an h n

\end{document}

```

I would like to do this, but basing the output on the character *before* my command.