[mcclim-devel] Proposed patch to format-graph-from-roots

Robert Goldman rpgoldman at real-time.com
Sun Sep 16 16:26:47 UTC 2007

A discussion on #lisp the other day pointed out that destructively
modifying &rest argument lists is not kosher.  format-graph-from-roots
does just that.

Would anyone object to me committing the following patch?

--- graph-formatting.lisp       4 Mar 2007 22:26:22 -0000       1.20
+++ graph-formatting.lisp       16 Sep 2007 16:25:26 -0000
@@ -115,9 +115,11 @@ (define-graph-type :directed-graph digra
 (define-graph-type :digraph digraph-graph-output-record)

 ;;;; Entry
+(defun format-graph-from-root (root-object &rest other-args)
+  (apply #'format-graph-from-roots (list root-object) other-args))

 (defun format-graph-from-roots (root-objects object-printer
-                                &rest graph-options
+                                &rest rest-args
                                 &key stream orientation cutoff-depth
                                      merge-duplicates duplicate-key
@@ -128,6 +130,9 @@ (defun format-graph-from-roots (root-obj
                                      graph-type (move-cursor t)
   (declare (ignore orientation generation-separation
within-generation-separation center-nodes))
+  ;; we were destructively modifying the &rest arg, which isn't safe,
+  ;; so I introduced the copy-list [2007/09/07:rpg]
+  (let ((graph-options (copy-list rest-args)))
   ;; Mungle some arguments
   (check-type cutoff-depth (or null integer))
   (check-type root-objects sequence)
@@ -184,7 +189,7 @@ (defun format-graph-from-roots (root-obj
         (setf (stream-cursor-position stream)
               (values (bounding-rectangle-max-x graph-output-record)
                       (bounding-rectangle-max-y graph-output-record))))
-      graph-output-record)))
+       graph-output-record))))

 (defun format-graph-from-root (root &rest rest)
   (apply #'format-graph-from-roots (list root) rest))
@@ -248,7 +253,7 @@ (defclass standard-graph-node-output-rec
     :initarg :object
     :reader graph-node-object)
-   ;; internal slots for the graph layout algorithmn
+   ;; internal slots for the graph layout algorithm
     :initform nil
     :accessor graph-node-minor-size


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