[cl-graph-devel] copying a graph

[Gary King]

P.S., I might also want to look at copy-template in moptilities. Here  
is the documentation (sorry about wrapping)

;;;  
------------------------------------------------------------------------ 
---
;;; copy-template
;;; suppose you have an object
;;; ? (defclass foo ()
;;;     ((test :accessor test :initform #'equal :initarg :test))) =>
;;; #<STANDARD-CLASS FOO>
;;;
;;; ? (setf *foo* (make-instance 'foo :test #'eql))
;;;
;;; ? (test *foo*) => #'eql
;;;
;;; Now you want to make another instance of foo that has the same  
test as *foo*.
;;;
;;; ? (setf *new-foo* (make-instance (type-of foo)))
;;;
;;; ? (test *new-foo*) => #'equal
;;;
;;; Wait, we wanted *new-foo* to have slot test to be #'eql.  This  
seems trival
;;; for simple objects, but consider this from make-filtered-graph
;;;
;;; (make-graph (type-of old-graph)
;;;              :vertex-test (vertex-test old-graph)
;;;              :vertex-key (vertex-key old-graph)
;;;              :edge-test (edge-test old-graph)
;;;              :edge-key (edge-key old-graph)
;;;              :default-edge-type (default-edge-type old-graph)
;;;              :default-edge-class (default-edge-class old-graph)
;;;              :directed-edge-class (directed-edge-class old-graph)
;;;              :undirected-edge-class (undirected-edge-class old- 
graph))))
;;; Yuck!
;;;
;;; So we offer copy-template as a reasonable, though not perfect,  
solution
;;;  
------------------------------------------------------------------------ 
---



On Mar 21, 2006, at 12:57 PM, Alexis Gallagher wrote:

> Hi,
>
> Is there a way to make a (deep) copy of a graph? I've looked in the
> library and I can't find anything like copy-graph, copy-edge, or
> copy-vertex.
>
> I'm wondering about this, because I discovered I couldn't build a
> transformed version of a graph just by creating a new graph object and
> then adding edges from the old one. But if I can't do that, then  
> what is
> the best way to write functions that transform a graph  
> nondestructively?
>
> If I wanted to write such a function, is there anything I should know
> about which information needs to be preserved so that the duplicate
> object functions correctly with the other tools in the system?
>
> Cheers,
> alexis
>
> p.s. FYI, cl-graph adsf-installs fine on SBCL 0.9.7 on OS X. But I  
> still
> haven't got it working on CMUCL 19a / Debian stable. Has anyone else?
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-- 
Gary Warren King
metabang.com
http://www.metabang.com/