regular expression substittion function?

Are there any plans to provide a regular expression substitution function,
similar to translate but allowing more complex substitutions?

This is an example of what I want to use it for. I am using a query that
builds web urls from a couple of different types of data and then union
together. Some of the data is raw urls, and some is title information
that gets turn into search urls. The title information needs to be
massaged before being used in a url and it needs to be done in the query
if I want to do the union. The translate command could be used in my
particular case, but it will be very long, as I need to delete most
nonletter nondigit characters and change spaces to plusses. A regular
expression describing what I want would be much more compact.