5 files changed, 49 insertions(+), 20 deletions(-)

M lib/dhall/as_dhall.rb
M lib/dhall/coder.rb
M lib/dhall/normalize.rb
M test/test_as_dhall.rb
M test/test_coder.rb

@@ 153,6 153,10 @@ module Dhall
 					ut, tags = AsDhall.union_of(@values.zip(@types))
 
 					List.new(elements: @exprs.zip(tags).map do |(expr, tag)|
+						if expr.is_a?(Dhall::Union) && expr.alternatives.empty?
+							expr = expr.is_a?(Dhall::Enum) ? nil : expr.extract
+						end
+
 						Dhall::Union.from(ut, tag, expr)
 					end)
 				end

@@ 121,13 121,16 @@ module Dhall
 				end
 			end
 
+			refine Enum do
+				def to_ruby
+					extract == :None ? nil : extract
+				end
+			end
+
 			refine Union do
 				def to_ruby
-					if !value.nil? && tag.match(/\A\p{Upper}/) &&
-					   Object.const_defined?(tag)
+					if tag.match(/\A\p{Upper}/) && Object.const_defined?(tag)
 						yield extract, Object.const_get(tag)
-					elsif extract == :None
-						nil
 					else
 						yield extract
 					end

@@ 335,6 335,12 @@ module Dhall
 		end
 	end
 
+	class Enum
+		def normalize
+			with(alternatives: alternatives.normalize)
+		end
+	end
+
 	class If
 		def normalize
 			normalized = super

@@ 122,6 122,8 @@ class TestAsDhall < Minitest::Test
 				"Natural" => Dhall::Builtins[:Natural],
 				"Text"    => Dhall::Builtins[:Text],
 				"None"    => nil,
+				"boop"    => nil,
+				"Object"  => Dhall::EmptyRecordType.new,
 				"Bool"    => Dhall::Builtins[:Bool],
 				hash_key  => Dhall::RecordType.new(
 					record: {


@@ 140,6 142,8 @@ class TestAsDhall < Minitest::Test
 				Dhall::Union.from(union_type, "Natural", Dhall::Natural.new(value: 1)),
 				Dhall::Union.from(union_type, "Text", Dhall::Text.new(value: "hai")),
 				Dhall::Union.from(union_type, "None", nil),
+				Dhall::Union.from(union_type, "boop", nil),
+				Dhall::Union.from(union_type, "Object", Dhall::EmptyRecord.new),
 				Dhall::Union.from(union_type, "Bool", Dhall::Bool.new(value: true)),
 				Dhall::Union.from(union_type, "Bool", Dhall::Bool.new(value: false)),
 				Dhall::Union.from(union_type, hash_key, Dhall::Record.new(


@@ 149,7 153,7 @@ class TestAsDhall < Minitest::Test
 					elements: [Dhall::Natural.new(value: 1)]
 				))
 			]),
-			[1, "hai", nil, true, false, { a: 1 }, [1]].as_dhall
+			[1, "hai", nil, :boop, Object.new, true, false, { a: 1 }, [1]].as_dhall
 		)
 	end
 

@@ 39,15 39,23 @@ class TestCoder < Minitest::Test
 		)
 	end
 
+	class EmptyObject
+		def ==(other)
+			other.is_a?(EmptyObject)
+		end
+	end
+
 	def test_dump_array_heterogenous
 		assert_equal(
-			"\x86\x04\xF6\x83\x00\x83\t\x82\v\xA4fDoublefDoublegNatural" \
-			"gNaturaldNone\xF6dTextdTextgNatural\x82\x0F\x01\x83\t\x82\v\xA4" \
-			"fDoublefDoublegNaturalgNaturaldNone\xF6dTextdTextdNone\x83\x00\x83" \
-			"\t\x82\v\xA4fDoublefDoublegNaturalgNaturaldNone\xF6dTextdText" \
-			"fDouble\xFA?\x80\x00\x00\x83\x00\x83\t\x82\v\xA4fDoublefDoubleg" \
-			"NaturalgNaturaldNone\xF6dTextdTextdText\x82\x12ehello".b,
-			Dhall::Coder.dump([1, nil, 1.0, "hello"])
+			"\x86\x04\xF6\x83\x00\x83\t\x82\v\xA4gNaturalgNaturaldNone" \
+			"\xF6vTestCoder::EmptyObject\x82\a\xA0dboop\xF6gNatural\x82" \
+			"\x0F\x01\x83\t\x82\v\xA4gNaturalgNaturaldNone" \
+			"\xF6vTestCoder::EmptyObject\x82\a\xA0dboop\xF6dNone" \
+			"\x83\t\x82\v\xA4gNaturalgNaturaldNone\xF6vTestCoder::EmptyObject" \
+			"\x82\a\xA0dboop\xF6dboop\x83\x00\x83\t\x82\v\xA4" \
+			"gNaturalgNaturaldNone\xF6vTestCoder::EmptyObject" \
+			"\x82\a\xA0dboop\xF6vTestCoder::EmptyObject\x82\b\xA0".b,
+			Dhall::Coder.dump([1, nil, :boop, EmptyObject.new])
 		)
 	end
 


@@ 105,15 113,19 @@ class TestCoder < Minitest::Test
 	end
 
 	def test_load_array_heterogenous
+		coder = Dhall::Coder.new(safe: Object) # unsafe coder
+
 		assert_equal(
-			[1, nil, 1.0, "hello"],
-			Dhall::Coder.load(
-				"\x86\x04\xF6\x83\x00\x83\t\x82\v\xA4fDoublefDoublegNatural" \
-				"gNaturaldNone\xF6dTextdTextgNatural\x82\x0F\x01\x83\t\x82\v\xA4" \
-				"fDoublefDoublegNaturalgNaturaldNone\xF6dTextdTextdNone\x83\x00\x83" \
-				"\t\x82\v\xA4fDoublefDoublegNaturalgNaturaldNone\xF6dTextdText" \
-				"fDouble\xFA?\x80\x00\x00\x83\x00\x83\t\x82\v\xA4fDoublefDoubleg" \
-				"NaturalgNaturaldNone\xF6dTextdTextdText\x82\x12ehello".b
+			[1, nil, :boop, EmptyObject.new],
+			coder.load(
+				"\x86\x04\xF6\x83\x00\x83\t\x82\v\xA4gNaturalgNaturaldNone" \
+				"\xF6vTestCoder::EmptyObject\x82\a\xA0dboop\xF6gNatural\x82" \
+				"\x0F\x01\x83\t\x82\v\xA4gNaturalgNaturaldNone" \
+				"\xF6vTestCoder::EmptyObject\x82\a\xA0dboop\xF6dNone" \
+				"\x83\t\x82\v\xA4gNaturalgNaturaldNone\xF6vTestCoder::EmptyObject" \
+				"\x82\a\xA0dboop\xF6dboop\x83\x00\x83\t\x82\v\xA4" \
+				"gNaturalgNaturaldNone\xF6vTestCoder::EmptyObject" \
+				"\x82\a\xA0dboop\xF6vTestCoder::EmptyObject\x82\b\xA0".b
 			)
 		)
 	end