package require nx

 nx::Class create Node {}


  nx::Class create Edge {
    :property n1:object,type=Node
    :property n2:object,type=Node

    :public method equals {e:object,type=Edge,required} {
      # Check if the nodes are equal
      if {[$e cget -n1] == ${:n1} && [$e cget -n2] == ${:n2}} {
        return true
      } elseif {[$e cget -n2] == ${:n1} && [$e cget -n1] == ${:n2}} {
        return true
      } else {
        return false
      }
    }
  }

  nx::Class create Graph {
    :property edges {}
    :property nodes {}
    :variable graph_string

    :private method add_edge {n1:object,type=Node,required n2:object,type=Node,required} {
      Edge create e1 -n1 $n1 -n2 $n2
      set checker 0
      foreach {key value} [array get ${:edges}] {
        if {e equals $value} {
          set checker 1
        }
      }

      if {checker == 1} {
        puts "The edge is in the list already"
      } else {
        lappend :edges $e
        :add_node $n1
        :add_node $n2
        :graph_string append
      }
    }

    :private method add_node {n:object,type=Node,required} {
      set checker 0
      foreach {key value} [array get :nodes] {
        if {$n == $value} {
          set checker 1
        }
      }

      if {checker == 0} {
        lappend :nodes $n
      }
    }

    :public method add {n1:object,type=Node,required n2:object,type=Node,required} {
        :add_edge $n1 $n2
    }
  }

  Node create n1
  Node create n2
  Edge create e1 -n1 n1 -n2 n2
  puts [e1 equals e1]
  Graph create g

  g add n1 n2