[plt-scheme] SRFI-9 usability issues

The implementation of SRFI-9 (Defining Record Types) included with
MzScheme uses make-struct-type to define the new type. It uses the
default inspector, which means that the new record type is opaque.
Because of that, the contents of a record can't be printed with DISPLAY
or WRITE, and EQUAL? can't check two records for deep equality.

SRFI-9 is silent on the issue of printing and comparing records,
although I believe that the reference implementation would permit
deep-equality testing, and it seems like the "right thing" to do. The
MzScheme implementation could do the same thing by adding a
"transparent" inspector to the make-struct-type call.
-- 
Bradd W. Szonye
http://www.szonye.com/bradd