Hello Andy, > > 1- setters, as in (define-method ((setter ...) (self <...>) ...) ...) > > should (also :)) be inherited
> As you mention this is https://debbugs.gnu.org/cgi/bugreport.cgi?bug=19770. Yep, but after carefully (re)reading your answer and the manual, doing some more tests, I came to the conclusion stated in my message (the newly sent message), which in summary says: our documentation says it will create the accessor, unless already created => this, to me, means that: (a) if the expansion code creates the accessor, it should be possible for users to use it on both <a> and <b> instances; (b) from the text of the manual itself, the user should be able to create the accessor him/herself, then redefine the (setter foo) method _without_ altering any semantic wrt to the situation users faces when they are in the (a) situation In other words, once a user defines a setter, both the setter and getter (auto created or not) should be available upon the class they belong to and all subclasses > I think we have an understanding about why things are the way they are > in GOOPS ... Good! And I understand you mostly have, if ot entirely inherited and not redefined the <situation> :) > In this case though I don't know how to make a consistent system with > the semantics you are looking for and without losing some of the speed > of the current system. I'm sorry to hear that, but then we should change the manual, since goops does not implement what is described... note that on a semantic ground, it does not make much sense to define a setter upon a inexistent 'variable location', so, to me, it makes more sense to implement what the manual says; I would definitely not consider speed here, not again semantic anyway, but instead implement what the manual says, maybe with a special note in the manual to explain, if there is?, a way to achieve the same result with better speed... (like using #:getter then define-method (setter foo) ... ?) > In short I think I just don't agree with this change as part of standard > GOOPS, so I propose the second solution: to make sure you can implement > the behavior you want as a user. What about using a wrapper define-class > macro > that removes "#:accessor foo" from its slot definitions and translates those > to > issue definitions like this: > > (define-method (foo (x <obj>)) (slot-ref x 'foo)) > (define-method ((setter foo) (x <obj>) val) (slot-set! x 'foo val)) Sure. Do you mean making such a wrapper available in 2.2.x (as opposed to each of us would have to write his own? By the way that is exactly what the clos protocol says defclass should be expanded to when using :accessor, see [2] for an sbcl session upon the same 'case' (adapted for syntax and argument order (setf method first argument _must_ be the value ...)) just in case you'd like to play with again, I have made the example code even simpler see [1] (comment/uncomment the definition of the slot with/without the #:accessor and reload, to see how guile 'behaves' in both case... To make it short :):), I'm fine to use the second solution, though allow me to insist upon the fact that it is 'weird', to me, that the actual implementation properly inherits the setter if the user does not define the accessor, but then there is no getter, and if the user defines the accessor, then the setter is not inherited anymore. Cheers, David [1] (define-class <a> () (width #:accessor width #:init-value 0) #;(width #:init-value 0)) (define-method ((setter width) (self <a>) val) ;; here comes complex code, computing earth orbit, captain's age... (pk "this is <a> !width setter method, hello!") (slot-set! self 'width val) val) (define-class <b> (<a>)) (define a1 (make <a>)) (define b1 (make <b>)) (set! (width a1) 10) (width a1) (set! (width b1) 10) (width b1) [2] (defclass <a> () ((width :accessor width :initform 0))) (defmethod (setf width) (val (self <a>)) ;; here comes complex code, computing earth orbit, captain's age... (format t "this is <a> (setf width) method, hello!") (setf (slot-value self 'width) val) val) (defclass <b> (<a>) ()) (defvar a1 (make-instance '<a>)) (defvar b1 (make-instance '<b>)) => * (setf (width a1) 10) this is <a> (setf width) method, hello! 10 * (width a1) 10 * (setf (width b1) 10) this is <a> (setf width) method, hello! 10 * (width b1) 10 *
pgp4Z_BehXyOM.pgp
Description: OpenPGP digital signature
