Re: When slots :type are used

  |From: Raymond Toy <[email protected]>
  |Date: Thu, 04 Dec 2008 09:27:29 -0500
  |
  |(defclass foo2 ()
  |  ((slot :type single-float :initform 1.2f0)
  |   (slot2)))
  |
  |(defclass bar ()
  |  ((a :type fixnum :initform 0)))
  |
  |(defparameter *o* (make-instance 'foo2))
  |
  |(defmethod setslot ((obj bar) val)
  |  (setf (slot-value *o* 'slot) val)
  |  (setf (slot-value obj 'a) val))
  |
  |
  |Compile up the previous code.  Then (setf (slot-value (make-instance
  |'foo2) 'slot) "string") signals an error.
  |
  |But (setslot (make-instance 'bar) 99) doesn't signal an error even
  |though we're assigning a fixnum to a slot of type single-float.
  |Hence, the change I made doesn't apply to slot-value in methods.  (I
  |guess slot-value in methods takes a different path.)

Yes, actually I believe this was also the motivating reason for making
this change in the first place: (see didier's original message)
viz. that setf slot-value was not triggering an error while setslot
was.  , So it was clear there were two different code paths, and you
added an explicit check-type to one of them.


  |I don't know PCL well enough to know exactly how methods get called or
  |which ones are run.

--
Regards
Madhu