Add RecordOf and FieldOf for homogeneous records

Author: paulyoung

src/Type/Data/Record.purs

@@ -0,0 +1,18 @@
+module Type.Data.Record
+  ( class RecordOf
+  ) where
+
+import Type.Row (class RowToList, Cons, Nil, kind RowList)
+
+class RecordOf record fieldType
+instance recordOf
+  :: ( RowToList record fields
+     , FieldOf fields fieldType
+     )
+  => RecordOf (Record record) fieldType
+
+class FieldOf (rowList :: RowList) fieldType
+instance fieldOfCons
+  :: (FieldOf tail fieldType)
+  => FieldOf (Cons symbol fieldType tail) fieldType
+instance fieldOfNil :: FieldOf Nil fieldType