diff --git a/src/andrew.cr b/src/andrew.cr
index 5f8c28c..45b8dc4 100644
--- a/src/andrew.cr
+++ b/src/andrew.cr
@@ -25,10 +25,22 @@ end
 class ClassGenerator
 	YAML.mapping(
 		name: String,
-		bitfields: Array(BitfieldGenerator),
-		attributes: Array(AttributeGenerator),
-		repeats: Array(RepeatGenerator),
-		attributeafters: Array(AttributeAfterGenerator)
+		bitfields: {
+			type: Array(BitfieldGenerator),
+			nilable: true
+		},
+		attributes: {
+			type: Array(AttributeGenerator),
+			nilable: true
+		},
+		repeats: {
+			type: Array(RepeatGenerator),
+			nilable: true
+		}, 
+		attributeafters: {
+			type: Array(AttributeAfterGenerator),
+			nilable: true
+		}
 	)
 
 	def initialize(@name : String)
diff --git a/src/views/class.ecr b/src/views/class.ecr
index c45b4e0..626e068 100644
--- a/src/views/class.ecr
+++ b/src/views/class.ecr
@@ -1,9 +1,11 @@
 
 class <%= @name %> {
 virtual <%= @name %>() = 0;
-<%- @attributes.each do |attr| -%>
+<% if !(@attributes.nil?) %>
+<%- @attributes.not_nil!.each do |attr| -%>
 
 <%= attr.to_s %>
 
 <%- end -%>
+<% end %>
 };
diff --git a/tests/record.yml b/tests/record.yml
index e1fd38b..264d5b1 100644
--- a/tests/record.yml
+++ b/tests/record.yml
@@ -45,7 +45,4 @@ classes:
         name: flags
         out_type: bitops::regulated<uint32_t>
         start: 40
-        class_name: record
-    bitfields: []
-    repeats: []
-    attributeafters: []
\ No newline at end of file
+        class_name: record
\ No newline at end of file