>
> if it's still feasible i suggest to replace REGISTER-IMMUTABLE-SYSTEM
> with (SETF SYSTEM-MUTABLE-P) and stop exporting *IMMUTABLE-SYSTEMS*.
>
I think it's too late to make changes for 3.1.5.

Indeed, it's probably a bad idea to export *IMMUTABLE-SYSTEMS*. Maybe
to late to fix in 3.1.5, but hopefully will be fixed in 3.2.

"Ask not what the government can do for you. Ask what the government is doing
to you." — David Friedman, "The Machinery of Freedom", p. 21

I think either way will work for us, but if register-immutable-system goes away, it will mean an application code change for us. We are not accessing *immutable-sytems* directly, so no worries there whether it's exported or not.

We do call register-immutable-systems, however.

For the record, here is how we are using it:

We make pre-built Gendl or Genworks GDL distributions which do not include any ASDF or Quicklisp at all, but they are built with monolithic-compile-bundles generated using asdf in our build environment.

For downstream users of prebuilt distributions who then want to load ASDF and Quicklisp, we provide a function, "load-quicklisp," which we ask users to call, rather than directly loading the quicklisp/setup.lisp themselves.

This function takes a :path keyword argument which defaults to the location of the quicklisp/ directory which we ship with our system. So if the user wants to use a different quicklisp/ directory (unsupported by us if they pick a different quicklisp version than what we built with and shipped), they can do it with that :path argument. The more usual case is that they copy our shipped quicklisp/ directory into a location where they have write access, because they want to put stuff into its local-projects/ or do other things which require write-access to the quicklisp/ directory.

The :path binds the dynamic variable *quicklisp-home*, as used in the following code:

(load (merge-pathnames "setup.lisp" *quicklisp-home*))

(defclass asdf::gdl (asdf::cl-source-file) ((type :initform "gdl")))

(defclass asdf::gendl (asdf::cl-source-file) ((type :initform "gendl")))

(defclass asdf::lisp (asdf::cl-source-file) ())

(let ((preloaded gdl::*already-loaded-systems*))

(dolist (system preloaded)

(asdf/find-system:register-immutable-system system)))

So as you can see, we maintain a variable gdl::*already-loaded-systems* (which probably ought to be exported, now that I mention it), which is used to establish the immutable-systems upon loading of quicklisp and asdf into the prebuilt image. And we do a few other extra initialization things after loading the quicklisp/setup.lisp.

My Best,

Dave Cooper
genworks.com, gendl.org
+1 248-330-2979