src/Pure/sorts.ML

   val insert_typ: typ -> sort OrdList.T -> sort OrdList.T
   val insert_typs: typ list -> sort OrdList.T -> sort OrdList.T
   val insert_term: term -> sort OrdList.T -> sort OrdList.T
   val insert_terms: term list -> sort OrdList.T -> sort OrdList.T
   type algebra
-  val rep_algebra: algebra ->
-   {classes: serial Graph.T,
-    arities: (class * (class * sort list)) list Symtab.table}
+  val classes_of: algebra -> serial Graph.T
+  val arities_of: algebra -> (class * (class * sort list)) list Symtab.table
   val all_classes: algebra -> class list
   val super_classes: algebra -> class -> class list
   val class_less: algebra -> class * class -> bool
   val class_le: algebra -> class * class -> bool
   val sort_eq: algebra -> sort * sort -> bool

 
 datatype algebra = Algebra of
  {classes: serial Graph.T,
   arities: (class * (class * sort list)) list Symtab.table};
 
-fun rep_algebra (Algebra args) = args;
-
-val classes_of = #classes o rep_algebra;
-val arities_of = #arities o rep_algebra;
+fun classes_of (Algebra {classes, ...}) = classes;
+fun arities_of (Algebra {arities, ...}) = arities;
 
 fun make_algebra (classes, arities) =
   Algebra {classes = classes, arities = arities};
 
 fun map_classes f (Algebra {classes, arities}) = make_algebra (f classes, arities);