18 Graph Formatting

CLIM provides a mechanism for arranging arbitrary output in a graph. The following code produces the graph shown in Figure 18.1. [annotate]

(defun graph-test (stream &optional (orientation :horizontal)) 
  (fresh-line stream)
  (macrolet ((make-node (&key name children)
               `(list* ,name ,children)))
    (flet ((node-name (node)
             (car node))
           (node-children (node)
             (cdr node)))
      (let* ((2a (make-node :name "2A"))
             (2b (make-node :name "2B"))
             (2c (make-node :name "2C"))
             (1a (make-node :name "1A" :children (list 2a 2b)))
             (1b (make-node :name "1B" :children (list 2b 2c)))
             (root (make-node :name "0" :children (list 1a 1b))))
        (format-graph-from-roots
          (list root)
          #'(lambda (node s)
              (write-string (node-name node) s))
          #'node-children
          :orientation orientation
          :stream stream)))))

Figure 18.1: Example of graph formatting.