Contents

require 'forwardable'
require 'tangle/errors'

module Tangle
  #
  # An edge in a graph, connecting two vertices
  #
  class Edge
    include Tangle::Mixin::Initialize

    attr_reader :name

    # Create a new edge between vertices
    #
    # Edge.new(vtx1) => Edge (loop)
    # Edge.new(vtx1, vtx2) => Edge
    #
    # End users should probably use Graph#add_edge instead.
    #
    def initialize(vertex1, vertex2 = vertex1, name: nil, **kwargs)
      @name = name
      initialize_vertices(vertex1, vertex2)
      initialize_mixins(**kwargs)
    end

    def [](from_vertex)
      @vertices[from_vertex]
    end

    def walk(from_vertex)
      @vertices.fetch(from_vertex)
    end

    def to_s
      vertex1, vertex2 = @vertices.keys
      "{#{vertex1}<->#{vertex2}}"
    end
    alias inspect to_s

    def each_vertex(&block)
      @vertices.each_key(&block)
    end

    def include?(vertex)
      each_vertex.include?(vertex)
    end

    def loop?
      @loop
    end

    private

    def initialize_vertices(vertex1, vertex2 = vertex1)
      @loop = vertex1 == vertex2
      @vertices = { vertex1 => vertex2, vertex2 => vertex1 }.freeze
    end
  end
end

Version data entries

4 entries across 4 versions & 1 rubygems

Version	Path
tangle-0.9.0	lib/tangle/edge.rb
tangle-0.8.2	lib/tangle/edge.rb
tangle-0.8.1	lib/tangle/edge.rb
tangle-0.8.0	lib/tangle/edge.rb