I've set the garbage collector work aside for a week and have been hacking on another home project. I've written a C header file parser for Common Lisp. This code digests header files that have been run through the C preprocessor and parses the subset of C that is likely to be in a header file i.e., most things other than function bodies. Constant expressions are supported. A parse tree, with each element of C grammer represented as a CLOS object, is produced. I've also written some code that walks that parse tree and emits the def-alien declarations for CMU CommonLisp. So, maybe we're a little bit closer to automatically interfacing with C? Maybe. I hope to make an initial release by the end of the week.