diff --git a/build/ruby/lib/tucana/shared/shared.data_type.rb b/build/ruby/lib/tucana/shared/shared.data_type.rb
index 85e919f..8bdb2e6 100644
--- a/build/ruby/lib/tucana/shared/shared.data_type.rb
+++ b/build/ruby/lib/tucana/shared/shared.data_type.rb
@@ -26,6 +26,8 @@ def rule_config
           self.input_types
         when :return_type
           self.return_type
+        when :parent_type
+          self.parent_type
         else
           raise UnexpectedRuleType, "Unknown rule type #{variant}"
         end
@@ -47,6 +49,8 @@ def create(variant, config)
           self.input_types = DefinitionDataTypeInputTypesRuleConfig.new(config)
         when :return_type
           self.return_type = DefinitionDataTypeReturnTypeRuleConfig.new(config)
+        when :parent_type
+          self.parent_type = DefinitionDataTypeParentTypeRuleConfig.new(config)
         else
           raise UnexpectedRuleType, "Unknown rule type #{variant}"
         end
@@ -159,6 +163,18 @@ def self.from_hash(config)
       end
     end
 
+    DefinitionDataTypeParentTypeRuleConfig.class_eval do
+      def to_h
+        {
+          parent_type: self.parent_type,
+        }
+      end
+
+      def self.from_hash(config)
+        new(parent_type: DataTypeIdentifier.from_hash(config[:parent_type]))
+      end
+    end
+
     DataTypeIdentifier.class_eval do
       def to_h
         {
diff --git a/build/ruby/spec/tucana/shared/shared.data_type_spec.rb b/build/ruby/spec/tucana/shared/shared.data_type_spec.rb
index 511284c..9946064 100644
--- a/build/ruby/spec/tucana/shared/shared.data_type_spec.rb
+++ b/build/ruby/spec/tucana/shared/shared.data_type_spec.rb
@@ -60,6 +60,14 @@
       end
     end
 
+    context "with :parent_type variant" do
+      it "sets the parent_type field" do
+        config = { parent_type: { data_type_identifier: "test_type" } }
+        rule = described_class.create(:parent_type, config)
+        expect(rule.parent_type).to be_a(Tucana::Shared::DefinitionDataTypeParentTypeRuleConfig)
+      end
+    end
+
     context "with unknown variant" do
       it "raises UnexpectedRuleType error" do
         expect {