Identify \Sexpr call?

More or less in the same vein as Henrik's post, is it possible to detect
that a function is being called in an \Sexpr when generating an Rd file?

Thank you

Sure:  have it check for a variable (or option or environment setting, 
or whatever) that was created in an earlier \Sexpr.

Or take your life in your hands, and look back up the call stack.

Duncan Murdoch