Re:Common Lisp Problems-Can't write a code walker

[Jim Kempf <kempf%hplabsc@hplabs.ARPA>]

I'll be interested in seeing further problems that arose with
writing a code walker for Portable Common Loops. Some of the
problems mentioned in the original posting were addressed
in a proposal for modifications to Common Lisp which we
felt were needed to portably implement CommonObjects.
Alan Snyder presented the document at the December Common Lisp
meeting. In particular, querying the environment object
passed to macros for information on declarations was mentioned.
CommonObjects doesn't do code-walking, since we have an extension
to our Common Lisp which allows us to establish macro-like
substitutions for symbols (a kind of symbol macro), that was
needed in order to implement instance variables with proper
scoping. I think that being able to easily implement a portable
code-walker in Common Lisp is generally desirable, however.
	Jim Kempf		kempf@hplabs