coloring keywords in the whole document

Question

Is there a way to color keywords into a document?

For instance, I want all the occurrences of a given word to appear in red in the whole document.

something like :

\colorize{red}{keywords={foo,bar}}

Answer 1

Just to elaborate a little on my comment. You could use spelling with LuaLaTeX like this:

\RequirePackage{filecontents}
\begin{filecontents*}{\jobname.spb}
foo
bar
\end{filecontents*}

\documentclass{article}
\usepackage{fontspec}
\usepackage{spelling}

\begin{document}

Keyword foo in text.

Keyword bar in text.

\end{document}

This will highlight foo and bar. You'll need two compilations.

Answer 2

AFAIK there is no such way, the easiest would be to use search & replace. Using LuaTeX however it should be possible. I have seen a presentation about the chickenize package once which showed similar features. LuaTeX is able to hook into the text output before it is written to the PDF.

Here's a link to the German presentation PDF: http://www.dante.de/events/mv45/Programm/atrautmann/folien-trautmann.pdf