add named references

object may determine own reference by
defining sof_reference_name
(some tests but surely more needed)

test/test_all.rb

@@ -3,3 +3,4 @@ require_relative "test_object"
 require_relative "test_ext"
 require_relative "test_refs"
 require_relative "test_super"
+require_relative "test_names"

test/test_names.rb

@@ -0,0 +1,29 @@
+require_relative "helper"
+class NamedRef < ObjectWithAttributes
+  def initialize name
+    super()
+    @name = name
+  end
+  def sof_reference_name
+    @name.to_s
+  end
+end
+
+class NamedTest < MiniTest::Test
+  include Checker
+
+  def test_object_one
+    object = NamedRef.new("one")
+    object.extra = [object]
+    @out = [ {:one => object} , object ]
+    check "- {:one => ->one}\n- &one NamedRef(:name => 'one', :number => 1234, :extra => [->one])"
+  end
+  def test_object_two
+    object = NamedRef.new("one")
+    object2 = NamedRef.new("two")
+    object.extra = [object2]
+    @out = [ {:one => object} , object2 ]
+    check "- - :one => NamedRef(:name => 'one', :number => 1234, :extra => [->two])\n- &two NamedRef(:name => 'two', :number => 1234)"
+  end
+
+end