Examples of programs with suboptions

Hi all,

I'm looking to review a few programs' ado files that have suboptions. By suboptions I mean options within options. E.g. ylabel() is an option of twoway, and labsize() is a suboption of ylabel, so if we were writing a twoway graph it might look like:

I'm writing a graphing program and my syntax so far is:

I'd like to give users suboptions within ylabel() for suffix() and prefix() where they could input string values like '%' or '$', but am not sure how to operationalize this in the syntax code. If anyone knows of a few ado files that include suboptions i'd appreciate some pointers. I've looked through a load of programs i've installed but so far haven't found one.

Best,
Chris