Add bin and edit workflow

bin/gems/facets-3.1.0/lib/standard/facets/equitable.rb

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+# = Equitable
+#
+# This mixin provides methods of equality based
+# on a single #identity method which must return
+# a list of accessors used as the identity keys.
+#
+# It also provides a "shortcut" for creating the
+# #identity method based on given accessors and returns
+# the Equitable module for inclusion.
+#
+#   include Equitable(:a, :b)
+#
+# is equivalent to including a module containing:
+#
+#   def ==(other)
+#     self.a == other.a && self.b == other.b
+#   end
+#
+#   def eql?(other)
+#     self.a.eql?(other.a) && self.b.eql?(other.b)
+#   end
+#
+#   def hash()
+#     self.a.hash ^ self.b.hash
+#   end
+#
+module Equitable
+
+  def self.identify(base, *accessors)
+    base.send(:define_method, :identity){ accessors }
+    self
+  end
+
+  def ==(o)
+    identity.all?{ |a| send(a) == o.send(a) }
+  end
+
+  def eql?(o)
+    identity.all?{ |a| send(a).eql?(o.send(a)) }
+  end
+
+  def hash
+    identity.inject(0){ |memo, a| memo ^ send(a).hash }
+  end
+
+end
+
+class Module
+
+  # This function provided a "shortcut" for creating the
+  # #identity method based on given accessors and returns
+  # the Equitable module for inclusion.
+  #
+  #  include Equitable(:a, :b)
+  #
+  # is equivalent to including a module containing:
+  #
+  #   def ==(other)
+  #     self.a == other.a && self.b == other.b
+  #   end
+  #
+  #   def eql?(other)
+  #     self.a.eql?(other.a) && self.b.eql?(other.b)
+  #   end
+  #
+  #   def hash()
+  #     self.a.hash ^ self.b.hash
+  #   end
+  #
+
+  def Equitable(*accessors)
+    Equitable.identify(self, *accessors)
+  end
+
+end
+