I'm quite indebted to Gerl Mollermann and Christophe Rhodes for their outstanding work on improving the MOP (Metaobject Protocol) implementations in SBCL and CMUCL. The latest set of hyperobject improvements exposed bugs in both SBCL and CMUCL. Gerd and Christophe find and squash bugs in a matter of hours. With their efforts, the MOP implementations in these Common Lisp implementations have reached the high level of AMOP compliance that I've found with AllegroCL. Along with better AMOP compliance and big bug reductions, Gerd's 18e+ MOP incorporates big performance optimizations in CMUCL.
With their improvments, I've generalized the attributes slot metaclass in my kmrcl helper package to work with CMUCL, SBCL, and SCL in addition to the long-standing AllegroCL support.
