(use srfi-69)

(define NODES 10)
(define EDGES 5)

(define graph (make-hash-table))

(define (insert-edges)
  (printf "~N Hash-tables - Inserting edges ~N")
  (do ((n 1 (+ n 1))) ((= n NODES))
    (do ((e 2 (+ e 1))) ((= e EDGES))
      (printf "n = ~A  |  e = ~A ~N" n e)
      (hash-table-update!/default graph
                                  n
                                  (lambda (v)
                                    (if (hash-table? v)
                                        (printf "v = ~A ~N~N" (hash-table->alist v))
                                        (printf "No hash table! v = ~A ~N~N" v)))
                                  (alist->hash-table `((,e)) )))))

(time (insert-edges))