graph-to-dot.rkt

;; Render a graph in dot format. Graph is a hash from nodes to sets of
;; nodes. Terminal nodes need not be included in the domain of graph.
(define (graph->dot graph)
  (define nodes (foldl (lambda (k s) (set-add (set-union (hash-ref graph k) s) k)) (set) (hash-keys graph)))
  (define nodesl (set->list nodes))
  (define node->num
    (foldl (lambda (i h) (hash-set h (list-ref nodesl i) i)) (hash) (range (length nodesl))))
  (displayln "digraph sloggraph {")
  (for ([i (range (length nodesl))])
    (displayln (format "\tn~a [label=\"~a\"];" i (string-replace
                                                  (string-replace (pretty-format (list-ref nodesl i)) "\n" "\\n") "\"" "\\\""))))
  (for ([key (hash-keys graph)])
    (for ([value (set->list (hash-ref graph key))])
      (displayln (format "\tn~a -> n~a [color=blue];" (hash-ref node->num key) (hash-ref node->num value)))))
  (displayln "}"))