> From: Joe Marshall <[email protected]>
> Date: Fri, 7 May 2010 11:43:00 -0700
>
> I want to intern some objects, but I want to be able to fasdump and
> fasload them, too. Is there any reasonable way (or unreasonable,
> for that matter), to hook into the fasloader to intern things when
> they are restored?
A simple test can determine if your object was recently fasloaded, at
which point you can re-intern (on-demand). E.g.
(define-structure thing tag unique)
(define (thing.unique t)
(if (eq? unique-tag (thing-tag t))
(thing-unique t)
(let ((new (re-intern-unique (thing-unique t))))
(set-thing-unique! t new)
(set-thing-tag! t unique-tag)
new)))
;; This cannot match any fasloaded string, until some smart-*ss
;; adds fancy constant string sharing yabber to my KISS runtime... :-}
(define unique-tag "constant string, shared or not")
The real trick is cutting your objects off from their methods. These
insidious devils are (one?) reason why this happens:
1 ]=> (fasdump (make-thing unique-tag 'stand-in) "thing.bin")
;Dumping "thing.bin"...
;Object cannot be dumped because it contains an environment: #[thing 19]
;To continue, call RESTART with an option number:
and why I have been heard to incant:
(define-structure (alien-function
;; To be fasdump/loadable.
(type vector) (named 'alien-function)
...)
...)
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