Re: EIEIO accessing class slots

[Stefan Monnier <monnier@iro.umontreal.ca>]

>>     (oref-default 'moirai-dired-side :display-alist)
>> instead of
>>     (oref-default 'moirai-dired-side 'display-alist)
>> ?
> because it don't work.

Oh, that's right `oref` and `oref-default` are macros, which quote their
second arg, contrary to `slot-value` which is a function and is the
more "normal" accessor.
But there's no `slot-value-default`, indeed.

[ Side note: Using the slot name, as in (oref-default 'moirai-dired-side
  display-alist), is more efficient than using the initarg name, as in
  (oref-default 'moirai-dired-side :display-alist), which is deprecated.  ]

>> Also, why do you need to do (oref-default 'moirai-dired-side
>> :display-alist), what do you expect it to return?
> The default value inherited by some of the objects.

But this is a lie :-(
The real semantics of the "default value" is a lot more murky.
It works like you expect only when the default value is defined as
a constant.

>> If you expect it to return the ((moirai-dired-p) ...)
>> you specified in the `defclass`, then why not do:
>>     (defvar foo-bar '((moirai-dired-p) ...))
>> so you can get this value without having to ask the class?
> Is that terrible to ask to the class ?

To the extent that it doesn't exist in CLOS, then I think it's better to
avoid using this functionality ;-)


        Stefan