Can you get Variables to be evaluated during page publish, or even page render?

[Graham Foster]

I'm aware of how Variables can be used with page templates as a 1 off substitution of information when the page is initially created.

What I'm wondering is - is there any way for variables to be substituted at Publish time, or even at the time a page is rendered? This would mean that the underlying page could remain independently authored for as long as possible.

I'm thinking of text substitution like you find with C pre-processors, using #defined and #include to allow you to specify in 1 place something that might change.

E.g. defining $$PRODUCTNAME and $$PRODUCTLOGOLINK in a central #include file, would mean that you could reference $$PRODUCTNAME or the logo in the main help pages, and only have to define it in 1 place. So when your marketing department come along and rebrand your product, you might be able to get away with changing 1 text string and a URL in the #include file, republish the site - and the rebranding would be done

I'm aware that you can do large Includes for sections of a page (I think that works similarly), but I'm not sure if you can use this for small textual substitutions as I indicated above.

Anyone got any ideas?