[plt-scheme] archival docs on arity

From: Shriram Krishnamurthi (sk at cs.brown.edu)
Date: Wed Sep 9 15:33:26 EDT 2009

I argued for the inclusion of ARITY on the grounds that some other
Scheme (Chez?) had it -- and I needed it for the first debugging
support code I wrote.

Posted on the users mailing list.