I am not an attorney and I couldn't care less about Stallman and his GPL, my analysis of that statement is as follows.

The first sentence gives permission to use and modify it as we see fit - essentially public domain.

The second sentence does not say the code can't be exported outside the US.  It says it can't be exported if it violates any export laws of the US.  That sentence has almost no meaning.  Anyone who writes code that is restricted from export (e.g. encryption code, advanced rocket guidance systems etc.) is restricted from exporting it whether it has that statement in it or not.  The people who put it there just put it in to cover their a**.  Neither the US government nor the authors could possible care less who uses that code.  There are no top secrets in it and EVERYONE knows that the entire world has already had access to both the book and the code.

I hope no decisions are going to be made based on the statement in the code.

Blake McBride

On Tue, Jan 20, 2009 at 8:56 AM, Ville Voutilainen <ville.voutilainen@gmail.com> wrote:
On Tue, Jan 20, 2009 at 4:44 PM, Blake McBride <blake@mcbride.name> wrote:
> Greetings,
> The book "The Art of the Metaobject Protocol" by Kiczales, Rivieres & Bobrow
> contains a simplified but working CLOS.  It is infinitely better than what's

While most of us are aware of AMOP, using the CLOS implementation (Closette,
found in http://www.scs.cmu.edu/afs/cs/project/ai-repository/ai/lang/lisp/oop/clos/closette/closette.tgz)
from that book will not do. It's copyright preamble contains the following:

;;; Use and copying of this software and preparation of derivative works
;;; based upon this software are permitted.  Any distribution of this
;;; software or derivative works must comply with all applicable United
;;; States export control laws.

Requiring compliance with US export control is incompatible with the GNU GPL.
So, unless we can integrate PCL, or find other suitable implementation
to integrate,
we'll have to implement AMOP as described by the book ourselves.