commit 2241bf9d20ca4c1c186ae945e4a8f8a84146ad24
Author: Sergiu Ivanov <sivanov@colimite.fr>
Date:   Sun Dec 27 22:46:49 2020 +0100

    Start the library with the idea of a solution from Alex Knauth.

diff --git a/main.rkt b/main.rkt
new file mode 100644
index 0000000..1f33ae2
--- /dev/null
+++ b/main.rkt
@@ -0,0 +1,32 @@
+#lang typed/racket
+
+;https://stackoverflow.com/questions/65386334/racket-generic-graph-library-in-typed-racket
+
+(module graph-wrapper racket
+  (require (prefix-in g: graph))
+  (provide graph?
+           directed-graph
+           has-edge?
+           graphviz)
+
+  (struct graph (g))
+
+  (define (directed-graph es [ws #f])
+    (graph (g:directed-graph es ws)))
+  (define (has-edge? g u v)
+    (g:has-edge? (graph-g g) u v))
+  (define (graphviz g #:output [output #f] #:colors [colors #f])
+    (g:graphviz (graph-g g) #:output output #:colors colors)))
+
+(require/typed 'graph-wrapper
+  [#:opaque Graph graph?]
+  [directed-graph (->* ((Listof (List Any Any))) ((Listof Any)) Graph)]
+  [has-edge? (-> Graph Any Any Boolean)]
+  [graphviz (->* (Graph)
+                 (#:output Output-Port
+                  #:colors (HashTable Any Natural))
+                 String)])
+
+(define g (directed-graph '((a b) (b c))))
+(has-edge? g 'a 'c)
+(graphviz g)