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From: Mario Lang <mlang@blind.guru>
To: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: emacs-devel@gnu.org
Subject: Re: EIEIO default constructor function
Date: Thu, 08 Apr 2021 05:37:07 +0200	[thread overview]
Message-ID: <87lf9t5twc.fsf@blind.guru> (raw)
In-Reply-To: <jwvk0piuoq2.fsf-monnier+emacs@gnu.org> (Stefan Monnier's message of "Sun, 04 Apr 2021 10:12:48 -0400")

Hi Stefan.

Thanks a lot.  :include is just what I was looking for.
And while `make-instance' and `slot-value' are convenient, I guess I can
work around not having them.  Having `initialize-instance' would
also have been convenient, but since I apparently only needed an :after
method I ended up using the :constructor option to rename the generated
constructor to indicate it is internal.
So it appears I can actually do without `defclass' and friends.

Stefan Monnier <monnier@iro.umontreal.ca> writes:

>> Maybe I was using sloppy terminology, but as far as I can see, `cl-defstruct'
>> can not have a parent relationship, so what I call inheritance-based
>> dispatch isn't really possible with cl-defstruct?
>>
>> (defclass foo () ())
>> (cl-defmethod val ((foo foo)) 0)
>> (defclass bar (foo) ())
>> (cl-defmethod val ((bar bar)) 1)
>
>     (cl-defstruct (my-foo)
>       slot1)
>     (cl-defmethod my-val ((x my-foo)) (my-foo-slot1 x))
>     (cl-defstruct (my-bar
>                    (:include my-foo))
>       slot2)
>     (cl-defmethod my-val ((x my-bar))
>       (+ (my-bar-slot2 x) (cl-call-next-method)))
>
>      (my-val (make-my-bar :slot1 4 :slot2 5))
>      ==> 9
>
>
> -- Stefan

-- 
CYa,
  ⡍⠁⠗⠊⠕



  reply	other threads:[~2021-04-08  3:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-03  3:50 EIEIO default constructor function Mario Lang
2021-04-03 13:48 ` Stefan Monnier
2021-04-04  2:42   ` Mario Lang
2021-04-04  3:10     ` Stefan Monnier
2021-04-04  8:39       ` Mario Lang
2021-04-04 14:12         ` Stefan Monnier
2021-04-08  3:37           ` Mario Lang [this message]
2021-04-08  4:44             ` Stefan Monnier

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