Relative/Variable Dates in CQL

First, is there a better place to have implementation discussions?

I'm wondering what the best way to support relative date queries.  For
example, suppose I use the Dublin Core Context Set's 'date' index,
what's the best way to craft a query that says "give me all documents
containing the word snoopy and have a date within 30 days of today".

So far, I've only thought up ways that define some variable that will
be substituted at runtime but I'm wondering if there isn't a more
elegant approach that actually uses the relations/relation modifiers
better?

Thanks,
--tim