Fix bug #18897 with printing large objects from eieio.el.

 lisp/emacs-lisp/eieio.el (eieio-edebug-prin1-to-string): Adjust
 for use as advice.
 (edebug-setup-hook): Advise `edebug-prin1-to-string'.

2 files changed, 14 insertions, 12 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 63663e878b9..ec6b21a7e95 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,9 @@
+2014-11-02  Eric Abrahamsen  <eric@ericabrahamsen.net>
+
+        * emacs-lisp/eieio.el (eieio-edebug-prin1-to-string): Adjust for
+        use as advice.
+        (edebug-setup-hook): Advise `edebug-prin1-to-string'.  (Bug#18897)
+
 2014-11-02  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * emacs-lisp/pp.el (pp-macroexpand-expression): Use macroexpand-1
diff --git a/lisp/emacs-lisp/eieio.el b/lisp/emacs-lisp/eieio.el
index d7c60dc6dd5..df2ce0f984b 100644
--- a/lisp/emacs-lisp/eieio.el
+++ b/lisp/emacs-lisp/eieio.el
@@ -853,17 +853,19 @@ of `eq'."
 
 ;;; Interfacing with edebug
 ;;
-(defun eieio-edebug-prin1-to-string (object &optional noescape)
+(defun eieio-edebug-prin1-to-string (print-function object &optional noescape)
   "Display EIEIO OBJECT in fancy format.
-Overrides the edebug default.
-Optional argument NOESCAPE is passed to `prin1-to-string' when appropriate."
+
+Used as advice around `edebug-prin1-to-string', held in the
+variable PRINT-FUNCTION.  Optional argument NOESCAPE is passed to
+`prin1-to-string' when appropriate."
   (cond ((class-p object) (eieio-class-name object))
         ((eieio-object-p object) (object-print object))
         ((and (listp object) (or (class-p (car object))
                                  (eieio-object-p (car object))))
          (concat "(" (mapconcat #'eieio-edebug-prin1-to-string object " ")
                  ")"))
-        (t (prin1-to-string object noescape))))
+        (t (funcall print-function object noescape))))
 
 (add-hook 'edebug-setup-hook
           (lambda ()
@@ -887,14 +889,8 @@ Optional argument NOESCAPE is passed to `prin1-to-string' when appropriate."
             (def-edebug-spec class-constructor form)
             (def-edebug-spec generic-p form)
             (def-edebug-spec with-slots (list list def-body))
-            ;; I suspect this isn't the best way to do this, but when
-            ;; cust-print was used on my system all my objects
-            ;; appeared as "#1 =" which was not useful.  This allows
-            ;; edebug to print my objects in the nice way they were
-            ;; meant to with `object-print' and `class-name'
-            ;; (defalias 'edebug-prin1-to-string 'eieio-edebug-prin1-to-string)
-            )
-          )
+            (advice-add 'edebug-prin1-to-string
+                        :around #'eieio-edebug-prin1-to-string)))
 
 
 ;;; Start of automatically extracted autoloads.