Fuzion • Idioms • Idiom # 40: Graph with adjacency lists

Idiom # 40: Graph with adjacency lists

Code

Running Example

ex40 is

  vertex(id i32) : ordered vertex
  is
    neighbors(g graph) Set vertex  is
      for
        r := psSet (lists.empty vertex), if      (vertex.this = e.a) r.add e.b
                                         else if (vertex.this = e.b) r.add e.a
                                         else                        r
        e in g.edges
      else
        r

    redef infix <= (b vertex) => id <= b.id

    redef asString => "v$id"

    redef orderedThis => vertex id  # NYI: may be removed when type 'like this' is supported

  edge(a, b vertex) is

  graph(edges Sequence edge) is

  v1 := vertex 1
  v2 := vertex 2
  v3 := vertex 3
  v4 := vertex 4
  v5 := vertex 5
  vertices := [ v1; v2; v3; v4; v5 ]
  edges := [ edge v1 v2;
             edge v2 v4;
             edge v3 v4;
             edge v3 v5;
             edge v4 v5 ]
  g := graph edges

  say (v3.neighbors g)

What are effects?

next: Idiom # 41: Reverse a string