Almost there

[Faré]

>> We did add better immutable-system support thanks to Dave Cooper,
>
> is this meant to be the final public API (an exported global variable
> that holds a hashtable)?
>
The final API is
(register-immutable-system "foo")
and, I suppose,
(sysdef-immutable-system-search "foo")
though I forgot to export said function... fixed.

> maybe a simple defun SYSTEM-MUTABLE-P and a setf variant would be better?
>
Maybe. I'll let Robert decide if he wants a way to make a system
mutable no more.
Up until now, the usage scenario was that systems would transition one
way only from mutable to immutable,
as you prepare an image for delivery.

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
Uniquely in us, nature opens her eyes and sees that she exists.
        — Raymond Tallis (1946–)