[slime-devel] Strange behavior in edit-definition

[Antonio Menezes Leitao]

Hi,

Helmut Eller <heller at common-lisp.net> writes:

> Antonio Menezes Leitao <aml at gia.ist.utl.pt> writes:
>
>> and maybe it was that 'package' variable being referenced after
>> changing to a different buffer that was causing the problem.  An hard
>> to believe explanation, I'm sure, but just in case, I experimented
>> replacing that 'package' variable by another gensym, using:
>
> I can believe that.  The reason for problems like this are those 
> -*- package: ... -*- file variables.  This make package a buffer local
> variable in Emacs and interacts badly dynamic bindings.  E.g.:
>
> (progn
>   (make-variable-buffer-local 'my-var)
>   (setq my-var 1)
>   (message "%s" my-var)
>   (let ((my-var 2))
>     (message "%s" my-var)
>     (with-temp-buffer 
>       (message "%s" my-var))))
>
> my-var in the temp buffer is nil.  One would think that a simple rule
> like: first search let-bound variables, then buffer local variables
> and then global variables would avoid such problems but this is
> obviously not what Emacs does.
>
> It's probably a good idea to avoid the -*- package: ... -*- thing as
> the file has probably a in-package form already or a least rename it
> to Package.
>
> I committed you change.  Thanks.

Here's another one that is causing problems:

(defun slime-repl-set-package (package)
  "Set the package of the REPL buffer to PACKAGE."
  (interactive (list (slime-read-package-name "Package: " 
					      (slime-find-buffer-package))))
  (with-current-buffer (slime-output-buffer)
    (let ((unfinished-input (slime-repl-current-input)))
      (destructuring-bind (name prompt-string)
          (slime-eval `(swank:set-package ,package))
        (setf (slime-lisp-package) name)
        (setf (slime-lisp-package-prompt-string) prompt-string)
        (slime-repl-insert-prompt "" 0)
        (insert unfinished-input)))))

Again, using pkg in place of package solves the problem but, as you
explained, the problem seems to be on Emacs and not on Slime.

Thanks for the explanation.

António Leitão.