[slime-devel] source path finding breaks in the presence of #.

[Andreas Fuchs]

Hi all,

I encountered a construct like the following in cl-irc. It makes the
source path finder in M-. break:

------------- C-c C-k, then M-. A RET ------------
(cl:defpackage :swank-bork
  (:use :cl))

(cl:in-package :swank-bork)

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defvar *foo* '(a b c)))

(defmacro define-foos (args)
  `(progn
    ,@(mapcar (lambda (arg)
                `(defun ,arg (,arg) ,arg))
              args)))

(define-foos #.*foo*)
------------- snip ------------

trying to M-. A or B or C will fail with "Error: The variable *FOO* is
unbound."

With Juho Snellman's help, I tracked this down to
swank::read-source-form. My current suspicion on why this is happening
is that it READs the form and doesn't bind *package* to the package
that the stream uses. This causes evaluation of the #. form to yield
bad results.

Unfortunately, I have no idea how to fix this, or if this is
fix-worthy at all. I guess read-source-form would have to try and find
a top-level in-package form somewhere, possibly expanding macros along
the way and digging into top-levelness preserving forms like eval-when
and progn. That would be a lot of work for this one error, in my eyes.

Thanks for any advice (or fixes (-8),
-- 
Andreas Fuchs, <asf at boinkor.net>, asf at jabber.at, antifuchs