Initform evaluates when defclass, and be shared it's value between instances

[mkamotsu]

:initform in defclass specification is

"This form is evaluated every time it is used to initialize the slot".

But evaluates when defclass, and be shared it's value between instances.

(defclass <inner> () ((slot-inner :accessor slot-inner :initarg slot-inner)))

(defclass <outer> () ((slot-outer :reader slot-outer :initform (create (class <inner>) 'slot-inner 'hoge))))

(let ((outer-1 (create (class <outer>)))
      (outer-2 (create (class <outer>))))
  (format (standard-output) "~S~%" (slot-inner (slot-outer outer-1)))
  ;; => HOGE
  (format (standard-output) "~S~%" (slot-inner (slot-outer outer-2)))
  ;; => HOGE
  (setf (slot-inner (slot-outer outer-1)) 'FUGA)
  (format (standard-output) "~S~%" (slot-inner (slot-outer outer-1)))
  ;; => FUGA
  (format (standard-output) "~S~%" (slot-inner (slot-outer outer-2)))
  ;; => Expected HOGE, but FUGA
  )

[sasagawa888]

Thank you for the report. I'll review it thoroughly.

[sasagawa888]

It may be an issue with setf. The accessor was not designed to handle nesting.

[sasagawa888]

Fixed.
I've made it so that when an instance is created using create, it now makes a copy of the :initform instance that was defined with defclass. It’s working well in that example. How about in other cases? If any issues arise, please report them.