core: simplify implementation of Description DSL by supporting descriptions as subject in Description.new

lib/rdf/description.ex

@@ -27,8 +27,12 @@ defmodule RDF.Description do
     do: new(statement) |> add(more_statements)
   def new(subject),
     do: %RDF.Description{subject: convert_subject(subject)}
+
+  def new(%RDF.Description{} = description, predicate, objects),
+    do: RDF.Description.add(description, predicate, objects)
   def new(subject, predicate, objects),
     do: new(subject) |> add(predicate, objects)
+
   def new(subject, statements) when is_list(statements),
     do: new(subject) |> add(statements)
   def new(subject, %RDF.Description{predications: predications}),

lib/rdf/vocabulary_namespace.ex

@@ -103,11 +103,6 @@ defmodule RDF.Vocabulary.Namespace do
             term_to_uri(@base_uri, term)
           end
 
-          def unquote(:"$handle_undefined_function")(term,
-                [%RDF.Description{} = description | objects]) do
-            RDF.Description.add(description, term_to_uri(@base_uri, term), objects)
-          end
-
           def unquote(:"$handle_undefined_function")(term, [subject | objects]) do
             RDF.Description.new(subject, term_to_uri(@base_uri, term), objects)
           end
@@ -197,10 +192,6 @@ defmodule RDF.Vocabulary.Namespace do
         @doc "`RDF.Description` builder for <#{@tmp_uri}>"
         def unquote(name)(subject, object)
 
-        def unquote(name)(%RDF.Description{} = description, object) do
-          RDF.Description.add(description, @tmp_uri, object)
-        end
-
         def unquote(name)(subject, object) do
           RDF.Description.new(subject, @tmp_uri, object)
         end

test/unit/description_test.exs

@@ -59,6 +59,15 @@ defmodule RDF.DescriptionTest do
       assert description_of_subject(desc, uri(EX.Subject))
       assert description_includes_predication(desc, {uri(EX.Predicate), uri(EX.Object)})
     end
+
+    test "with another description as subject, it performs and add " do
+      desc = Description.new({EX.S, EX.p, EX.O})
+
+      assert Description.new(desc, EX.p2, EX.O2) ==
+             Description.add(desc, EX.p2, EX.O2)
+      assert Description.new(desc, EX.p, [EX.O1, EX.O2]) ==
+             Description.add(desc, EX.p, [EX.O1, EX.O2])
+    end
   end