src/Pure/type.ML

   val infer_types: type_sig * typ Symtab.table * (indexname -> typ option) *
 		   (indexname -> sort option) * (typ -> string) * typ * term
 		   -> term * (indexname*typ)list
   val inst_term_tvars: type_sig * (indexname * typ)list -> term -> term
   val logical_type: type_sig -> string -> bool
-   val logical_types: type_sig -> string list
+  val logical_types: type_sig -> string list
   val merge: type_sig * type_sig -> type_sig
+  val rep_tsig: type_sig ->
+      {classes: class list, default: sort,
+       subclass: (class * class list) list,
+       args: (string * int) list,
+       coreg: (string * (class * sort list) list) list}
   val thaw_vars: typ -> typ
   val tsig0: type_sig
   val type_errors: type_sig * (typ->string) -> typ * string list -> string list
   val typ_instance: type_sig * typ * typ -> bool
   val typ_match: type_sig -> (indexname*typ)list * (typ*typ) ->

    coreg: a two-fold association list of all type arities; (t,al) means that
           type constructor t has the arities in al; an element (c,ss) of al
           represents the arity (ss)c
 *)
 
+fun rep_tsig (TySg comps) = comps;
 
 val tsig0 = TySg{classes = [],
 		 default = [],
 		 subclass = [],
 		 args = [],