Programmatically Drawing Simple Graphviz Graphs

For my book, I had to draw a number of graphs. Obviously, I wanted to have a programmatic way to do that, and Graphviz is the goto-library for that. In Lisp, the interface to Graphviz is cl-dot, but, for me, it wasn't easy to figure out from the manual the "simple and easy" way to use it. I.e. I couldn't find a stupid beginner-level interface, so I had to code it myself. Here's the implementation that allows anyone with a REPL to send to Graphviz lists of edges and obtain graph images.

	(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))

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Generated images: