>>>>> "Madhu" == Madhu <[email protected]> writes:
Madhu> * Raymond Toy <[email protected]> :
Madhu> Wrote on Wed, 10 Dec 2008 11:21:08 -0500:
Madhu> |>>>>> "dvl" == Didier Verna <[email protected]> writes:
Madhu> | dvl> But doing so by making (setf (slot-value))'s behavior
Madhu> | dvl> different (shall I say inconsistent?) depending on the
Madhu> | dvl> context feels somewhat weird to
Madhu> |
Madhu> | Raymond> Yes, I think it's inconsistent.
Madhu> |
Madhu> | dvl> me. I guess you concern is performance here; but then, we
can
Madhu> | dvl> play with the optimize declaration.
Madhu> The other concern was compatibility with other lisps which do not
signal
Madhu> an error when the type declaration is wrong. This particular
typecheck
Madhu> is not mandated by any spec, and lisps tend to let it pass.
Perhaps, but cmucl has always complained about stuff like this (when
compiled):
(defun foo (x) (declare (double-float x)) (sin x))
(foo 42)
Also, I want to make it a bit clearer. In the test case:
(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))
Then (setslot (make-instance 'bar) 42) does not signal an error when
assigning a fixnum to the single-float slot of class foo2. But
(setslot (make-instance 'bar) "abc") does signal an error about
assigning a string to a fixnum in the bar object. The difference is
that obj is an argument to the method. I think this has been this way
ever since Gerd added this ability.
The change I made was mostly for calling (setf slot-value) from the
repl. Perhaps the example above should also signal an error (if
safety is low enough). I don't know how to do either (signal an error
for *o* or make it not signal an error if safety is low enough).
Madhu> | Perhaps not the best solution, but I have made an internal change
so
Madhu> | that pcl::*use-slot-type-p* will be honored (at runtime). Hence,
type
Madhu> | checking will be done accordingly.
Madhu> Thanks, I have no problems setting pcl::*use-slot-types-p* when
Madhu> compiling code with incorrect typespecs but thinking out aloud [on
Madhu> behalf of the devil] perhaps the default behaviour should be a
warning
That would go against long-standing history of CMUCL signaling errors
for type issues. (Even if PCL historically didn't do this kind of
type checking until Gerd added it.)
Ray
