listings package : highlight word composed by an alphabetic and a numeric part

Question

I would like to highlight several keywords with an alphabetic and a numeric part with different color.

My problem is the number of keywords can become huge from r0 to r191 for example. And I have several keywords. Is there a way to escape to write all the possible keywords ?

Is there a way to define left delimiter just for a word and not for a line ?

The sample bellow do exactly what I want but with writing all the keywords (example keywords[2] and keywords[3])...

\documentclass[a4paper, 12pt,english]{article}
\usepackage{color}
\definecolor{gray}{rgb}{0.4,0.4,0.4}
\definecolor{darkgreen}{rgb}{0.0,0.4,0.0}
\definecolor{darkred}{rgb}{0.6,0.0,0.0}

\usepackage{listings}
\lstdefinelanguage{mylanguage}
                  {keywords=[1]{add,sub,test},
                    keywords=[2]{r0,r1,r2},
                    keywords=[3]{p00,p01,p10,p11},
                    moredelim=[s][\footnotesize\textit]{<}{>},
                    keywordstyle=[1]\normalsize\color{gray}\bfseries\ttfamily,
                    keywordstyle=[2]\color{darkgreen},
                    keywordstyle=[3]\color{darkred}}

\begin{document}

\lstset{numbers=left, numberstyle=\tiny, stepnumber=1, numbersep=5pt,language=mylanguage}
\begin{lstlisting}
  p00 add r0 , r1 , r2
\end{lstlisting}


\end{document}

Answer 1

Huge hat tip to David, first of all, for providing a solution to a tricky intermediate problem. I couldn't have done this without his help.

You can do this quite easily by simply generating the list with LaTeX itself (it is Turing-complete, after all, hehe). Notice that this requires the forloop package (a really simple macro, actually).

\documentclass[a4paper, 12pt,english]{article}
\usepackage{color,forloop}
\definecolor{gray}{rgb}{0.4,0.4,0.4}
\definecolor{darkgreen}{rgb}{0.0,0.4,0.0}
\definecolor{darkred}{rgb}{0.6,0.0,0.0}

\newcounter{ct}
\makeatletter
% Since we don't want an initial comma in the list, we use \@gobble
\def\rlist{\@gobble}
%  Using the counter ct, range its value from 0 to 191
\forloop{ct}{0}{\value{ct} < 192}{%
    % \edef expands the definition before it actually 
    % binds the two.  Thus, \rlist expands like a chameleon's tongue.
    \edef\rlist{\rlist,r\arabic{ct}}
  }

\makeatother
\def\listwithrs#1\relax{%
\lstdefinelanguage{mylanguage}
                  {keywords=[1]{add,sub,test},
                   keywords=[2]{#1},  % we stick in the list here
                   keywords=[3]{p00,p01,p10,p11},
                   moredelim=[s][\footnotesize\textit]{<}{>},
                   keywordstyle=[1]\normalsize\color{gray}\bfseries\ttfamily,
                   keywordstyle=[2]\color{red},
                   keywordstyle=[3]\color{darkred}}}

\usepackage{listings}

% Since we want to know the value of \rlist before we define the language,
% we use \expandafter to 'skip' \listwithrs so \rlist can be evaluated.
\expandafter\listwithrs\rlist\relax

\begin{document}

\lstset{numbers=left, numberstyle=\tiny, stepnumber=1, numbersep=5pt,language=mylanguage}
\begin{lstlisting}
  p00 add r0 , r1 , r2 , r3 , r4
\end{lstlisting}

\end{document}