typed-graph/graph.rkt

;;; Copyright 2021 Sergiu Ivanov <sivanov@colimite.fr>
;;;
;;; Licensed under the Apache License, Version 2.0 (the "License");
;;; you may not use this file except in compliance with the License.
;;; You may obtain a copy of the License at
;;;
;;;     http://www.apache.org/licenses/LICENSE-2.0
;;;
;;; Unless required by applicable law or agreed to in writing, software
;;; distributed under the License is distributed on an "AS IS" BASIS,
;;; WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
;;; See the License for the specific language governing permissions and
;;; limitations under the License.

#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)