gEDA-user: Hierarchy question

[Bill Cox <bill@viasic.com>]

Hi.

I can now read schematics and symbols into a temporary set of data 
structures, and build nets.  I'm working on writing the data structures 
to the netlist database.

How do I know what the top level pins for a schematic are?  I need to 
build a default symbol for the top level.  The use of flags makes sense, 
but the IO symbols don't seem to make much use of the device attribute. 
I don't know how to tell what's a flag.  How can I tell?

I'm thinking that flag symbols should set their device attribute to 
something like FLAG or IO.

Thanks,
Bill