Listings package: How can I format all numbers?

Question

I want to highlight all the numbers appearing in an input code of a certain program by, for example, coloring them. By numbers I mean integer, rational and floating point numbers. I am trying with the listings page but with no success. I have noticed that specific numbers can be formatted with the morekeywords and alsoletter options on defining the language but I want to acomplish this task for any number.

For example, I would like the code

vector([3/5,4,0.4566])

to appear with the three numbers with color green (or whatever). Is it possible to do this in an automatic way?

Answer 1

Similar to solutions in Visualization in LaTeX of hamming distance, and Problem with the alignment of characters, you could use the literate command to define a style that is to be applied to each digit. Below I included a color for the . but commented out the color for the ,.

As there might be a period used outside of a number context, I have defined different styles based on the assumption that any period used in a number will have a digit following it.

\documentclass[border=2pt]{standalone}
\usepackage{listings}
\usepackage{xcolor}

\lstdefinestyle{FormattedNumber}{%
    literate={0}{\textcolor{blue}{0}}{1}%
             {1}{\textcolor{blue}{1}}{1}%
             {2}{\textcolor{blue}{2}}{1}%
             {3}{\textcolor{blue}{3}}{1}%
             {4}{\textcolor{blue}{4}}{1}%
             {5}{\textcolor{blue}{5}}{1}%
             {6}{\textcolor{blue}{6}}{1}%
             {7}{\textcolor{blue}{7}}{1}%
             {8}{\textcolor{blue}{8}}{1}%
             {9}{\textcolor{blue}{9}}{1}%
             {.0}{\textcolor{blue}{.0}}{1}% Following is to ensure that only periods
             {.1}{\textcolor{blue}{.1}}{1}% followed by a digit are changed.
             {.2}{\textcolor{blue}{.2}}{1}%
             {.3}{\textcolor{blue}{.3}}{1}%
             {.4}{\textcolor{blue}{.4}}{1}%
             {.5}{\textcolor{blue}{.5}}{1}%
             {.6}{\textcolor{blue}{.6}}{1}%
             {.7}{\textcolor{blue}{.7}}{1}%
             {.8}{\textcolor{blue}{.8}}{1}%
             {.9}{\textcolor{blue}{.9}}{1}%
             %{,}{\textcolor{blue},}{1}% depends if you want the "," in color
             {\ }{ }{1}% handle the space
             ,
   basicstyle=\ttfamily,%  Optional to use this
}
\newcommand{\FormattedNumber}[1]{%
    \lstinline[style=FormattedNumber]{#1}%
}

\begin{document}
\FormattedNumber{a.vector([3/5,4,0.4566])}
\end{document}