Simple generation of graph images using dot (and cl-dot)

dwim-graph.lisp

(defclass dwim-graph () ())

(defmethod cl-dot:graph-object-node ((graph (eql 'dwim-graph)) object)
  (make-instance 'cl-dot:node
                 :attributes (list :label (format nil "~A" object)
                                   :shape :circle)))

(defmacro dwim-graph ((file &key (directed t)) &body edges)
    `(progn
       (eval-when (:compile-toplevel :load-toplevel :execute)
         (defmethod cl-dot:graph-object-edges ((graph (eql 'dwim-graph)))
           ,(coerce (mapcar (lambda (edge)
                              (destructuring-bind (beg end &rest args) edge
                                (append (list beg end)
                                        (unless directed `((:arrowhead :none)))
                                        args)))))
                            edges)
                    'vector)))
       (cl-dot:dot-graph
        (cl-dot:generate-graph-from-roots 'dwim-graph () '(:rankdir "LR"))
        ,file
        :format (intern (or (etypecase ,file
                              (pathname (pathname-type ,file))
                              (string (let ((dot-pos (position #\. ,file
                                                               :from-end t)))
                                        (when dot-pos
                                          (subseq ,file (1+ dot-pos))))))
                            "jpg")
                        :keyword))
       ,file))

#+directed-weighted-graph
(dwim-graph ("/tmp/g.jpg")
  (0 1 4)
  (0 2 4)
  (1 3 4)
  (1 4 1)
  (2 3 2)
  (2 4 2)
  (3 5 3)
  (4 5 5))

#+undirected-unweighted-graph
(dwim-graph ("/tmp/g.jpg" :directed nil)
  (0 1)
  (0 2)
  (1 3)
  (1 4)
  (2 3)
  (2 4)
  (3 5)
  (4 5))