This page is part of the web mail archives of SRFI 102 from before July 7th, 2015. The new archives for SRFI 102 contain all messages, not just those from before July 7th, 2015.
I'll admit that, along with Kent Dybvig, I'm no fan of arity inspection, for a jillion reasons. I think it's ill-conceived. But if it must happen, how about this: (procedure-arity PROC) returns two values, first, the minimum number of arguments, and second, whether additional arguments are permissible. This exactly covers the possibilities for standard Scheme. It is trivial to implement given any of the common facilities out there. It is clear and simple and easy to specify. Thomas