Re: [Gcl-devel] proposed find-restart bugfix

[Camm Maguire]

Hi Peter!  Thanks for looking into this!

1) I added an optional condition argument to compute-restarts a little
   while ago to address some test failures Paul was seeing.  It was
   just a placeholder argument, i.e. it is currently ignored, as there
   is no 'slot' in the restart structure yet to support it.  This
   would be straightforward to add, but I'd let this mini-project wait
   for a while due to 2).  This is why the item is still active on the
   web site.

2) There appears to be a possible lexical scope issue with the
   *restart-clusters* handling.  I put in some work around to
   clcs/handler.lisp so that Paul's tests could detect a restartable
   ('correctable') package error, but was a bit confused as to why this
   should be necessary.  Paul had written that I should ignore the
   restart code for now as he was unsure if the tests were accessing this
   information correctly.

3) The background discussions should still be accessible via the recent
   mailing list archives.

4) This having been said, your patch looks fine to me, but will
   obviously need to be supplemented as in 1) and 2).  You might want
   to slightly modify to something like this for readability:

 (defun find-restart (name &optional condition)
       (let ((restarts (if condition (compute-restarts condition) 
(kcl-top-restarts))))
         (dolist (restart restarts)
           (when (or (eq restart name)
                     (eq (restart-name restart) name))
             (return-from find-restart restart)))))

If you would like to commit either one, that would be fine with me.
Please note that should some analogous patch be committed to a lsp
file in the lsp or cmpnew directories, the corresponding .c, .h, and
.data files would have to be remade and committed as well.  In this
case, the lisp patch alone will suffice given the way the build is
currently structured.

Take care,


Peter Wood <address@hidden> writes:

> Hi
> 
> On the Savannah bug page for GCL, (Task #1521)
> 
> http://savannah.gnu.org/pm/task.php?func=detailtask&project_task_id=1521&group_id=879&group_project_id=375
> 
> "Summary:  (ANSI) COMPUTE-RESTARTS should take an optional parameter"
> 
> I believe there was a typo here, since #'compute-restarts _does_ take
> an optional parameter (a condition).  Perhaps the report should have
> refered to #'find-restarts which should (but doesn't in current GCL).
> 
> Anyway, here is a lightly tested proposed bugfix:
> 
> (in-package "CONDITIONS")
> 
> (defun find-restart (name &optional condition)
>   (if condition
>       (let ((restarts (compute-restarts condition)))
>         (dolist (restart restarts)
>           (when (or (eq restart name)
>                     (eq (restart-name restart) name))
>             (return-from find-restart restart))))
>     (let ((restarts (kcl-top-restarts)))
>       (dolist (restart restarts)
>         (when (or (eq restart name)
>                   (eq (restart-name restart) name))
>           (return-from find-restart restart))))))
> 
> (in-package "COMMON-LISP-USER")
> 
> Example usage:
> 
> >(find-restart 'abort)
> 
> #<RESTART.0>
> 
> >(find-restart 'abort (make-condition 'error))
> 
> #<RESTART.0>
> 
> >(find-restart 'foo )
> 
> NIL
> 
> >(find-restart 'foo (make-condition 'error))
> 
> NIL
> 
> May I check in this bugfix?
> 
> Regards,
> Peter
> 
> 
> 
> _______________________________________________
> Gcl-devel mailing list
> address@hidden
> http://mail.gnu.org/mailman/listinfo/gcl-devel
> 
> 

-- 
Camm Maguire                                            address@hidden
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