Re: Listing slots in CLOS



vanekl wrote:
Ken Tilton wrote:



vanekl wrote:

vanekl wrote:

Rupert Swarbrick wrote:

Hi,

Is there a function, which will return a list (or whatever) of the slots in a class that I've got an instance of? I'm working with a weird auto-
generated binding library, which I don't really understand... and I'd like to be able to eyeball the fields I can play with!

The only things I can find are slot-exists-p and slot-bound-p, which of course aren't quite what I'm after. If there's not a portable way to do this, I'm using sbcl.

Rupert



[211]> (asdf:oos 'asdf:load-op :closer-mop)
...
[212]> (defclass c1 () (a b))
#1=#<STANDARD-CLASS C1>
[213]> (defclass c2 (c1) (d e f))
#1=#<STANDARD-CLASS C2>
[214]> (closer-mop:compute-slots (find-class 'c2))
(#<CLOS:STANDARD-EFFECTIVE-SLOT-DEFINITION A #x2052E666>
#<CLOS:STANDARD-EFFECTIVE-SLOT-DEFINITION B #x2052E6A6>
#<CLOS:STANDARD-EFFECTIVE-SLOT-DEFINITION D #x2052E6E6>
#<CLOS:STANDARD-EFFECTIVE-SLOT-DEFINITION E #x2052E726>
#<CLOS:STANDARD-EFFECTIVE-SLOT-DEFINITION F #x2052E766>)

[217]> (dolist (slot (closer-mop:compute-slots (find-class 'c2)))
(print (closer-mop:slot-definition-name slot)))

A
B
D
E
F
NIL

originally posted by
__Pascal Bourguignon__



Disregard. This technique works in clisp 2.44 but not in sbcl,
at least not in sbcl 1.0.15.36.


I was wondering what that was all about. Seems to me compute-slots it is a tad lower-level than some of the other options, and that when it comes to flying in the face of a non-standard, the lower the worser.

kenny


Disregard the earlier disregard. This works on SBCL as long as you call:

(SB-MOP:FINALIZE-INHERITANCE (find-class 'c2))

before messing with the slots.

Great, but it is still the wrong entry point:

"Generic Function class-slots class

Returns a possibly empty set of the slots accessible in instances of class. The elements of this set are effective slot definition metaobjects.

During class finalization finalize-inheritance calls compute-slots to compute the slots of the class. That value is associated with the class metaobject and is returned by class-slots.

This generic function signals an error if class has not been finalized."

http://www.lisp.org/mop/dictionary.html#class-mo-readers

kt

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Relevant Pages

  • Re: Listing slots in CLOS
    ... vanekl wrote: ... The only things I can find are slot-exists-p and slot-bound-p, which of course aren't quite what I'm after. ... If there's not a portable way to do this, I'm using sbcl. ... Disregard. ...
    (comp.lang.lisp)
  • Re: Listing slots in CLOS
    ... If there's not a portable way to do this, I'm using sbcl. ... That value is associated with the class metaobject and is returned by class-slots. ... Class finalization is the step that is performed before the very first instance of a class is created. ... Clisp doesn't delay that step but finalizes classes immediately. ...
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  • Re: Listing slots in CLOS
    ... vanekl wrote: ... The only things I can find are slot-exists-p and slot-bound-p, which of course aren't quite what I'm after. ... If there's not a portable way to do this, I'm using sbcl. ...
    (comp.lang.lisp)
  • Re: Listing slots in CLOS
    ... Ken Tilton wrote: ... vanekl wrote: ... The only things I can find are slot-exists-p and slot-bound-p, which of course aren't quite what I'm after. ... If there's not a portable way to do this, I'm using sbcl. ...
    (comp.lang.lisp)