[slime-devel] MOP access

[Helmut Eller]

Rui Patrocínio <rui.patrocinio at netvisao.pt> writes:

> Hi,
>
>  Is there any access to MOP-like functionality in swank? I've not found
> it so I create a simple interface, similar to the xref one.

No, there is no such thing.

> swank.lisp:
> ;;; MOP
> (defslimefun mop (type symbol-name)
>   (let ((symbol (parse-symbol-or-lose symbol-name *buffer-package*)))
>     (ecase type
>       (:subclasses (class-direct-subclasses symbol))
>       (:superclasses (class-direct-superclasses symbol)))))
>
> Maybe 'mop' isn't the best name.

It is a least short :-)  If you add a docstrings, things should be fine.

> swank-cmucl.lisp:
> ;;; CLOS MOP
> (defimplementation class-direct-subclasses (class-name)
>   (handler-bind ((simple-error (lambda (c)
> 				 (declare (ignore c))
> 				 (return-from class-direct-subclasses
> 				   nil))))
>      (let* ((class (find-class class-name))
> 	    (subclasses (pcl:class-direct-subclasses class)))
>        (mapcar #'(lambda (x)
> 		   (symbol-name (pcl:class-name x)))
> 	       subclasses))))
[...]
>  The handler is to catch the errors of find-class with a class that
> doesn't exist. Maybe there's a better behaviour in that situation.

It might be simpler to export the MOP functions directly from the
swank-backend, e.g., just adding 

  (export 'pcl:class-direct-subclasses)

in swank-cmucl and the analog in the other backends.  This could save
us the work for inventing a new interface and the AMOP specification
is probably not that bad.  Whether the implementations agree with AMOP
specification is, of course, a different question. 

We can probably also save some code duplication if we move the error
handling and class->name translation to swank.lisp.

Helmut.