src/HOLCF/domain/extender.ML

fixed typid;

(*  Title:      HOLCF/domain/extender.ML
    ID:         $Id$
    Author : David von Oheimb
    Copyright 1995, 1996 TU Muenchen

Theory extender for domain section.
*)


structure Domain_Extender =
struct

local

open Domain_Library;

(* ----- general testing and preprocessing of constructor list -------------- *)

  fun check_and_sort_domain (dtnvs: (string * typ list) list, cons'' :
     ((string * mixfix * (bool*string*typ) list) list) list) sg =
  let
    val defaultS = Sign.defaultS sg;
    val test_dupl_typs = (case duplicates (map fst dtnvs) of 
	[] => false | dups => error ("Duplicate types: " ^ commas_quote dups));
    val test_dupl_cons = (case duplicates (map first (flat cons'')) of 
	[] => false | dups => error ("Duplicate constructors: " 
							 ^ commas_quote dups));
    val test_dupl_sels = (case duplicates 
			       (map second (flat (map third (flat cons'')))) of
        [] => false | dups => error("Duplicate selectors: "^commas_quote dups));
    val test_dupl_tvars = exists(fn s=>case duplicates(map(fst o rep_TFree)s)of
	[] => false | dups => error("Duplicate type arguments: " 
		   ^commas_quote dups)) (map snd dtnvs);
    (* test for free type variables, illegal sort constraints on rhs,
	       non-pcpo-types and invalid use of recursive type;
       replace sorts in type variables on rhs *)
    fun analyse_equation ((dname,typevars),cons') = 
      let
	val tvars = map rep_TFree typevars;
	fun distinct_name s = "'"^Sign.base_name dname^"_"^s;
	val distinct_typevars = map (fn (n,sort) => 
				     TFree (distinct_name n,sort)) tvars;
	fun rm_sorts (TFree(s,_)) = TFree(s,[])
	|   rm_sorts (Type(s,ts)) = Type(s,remove_sorts ts)
	|   rm_sorts (TVar(s,_))  = TVar(s,[])
	and remove_sorts l = map rm_sorts l;
	fun analyse(TFree(v,s)) = (case assoc_string(tvars,v) of 
		    None      => error ("Free type variable " ^ v ^ " on rhs.")
	          | Some sort => if eq_set_string (s,defaultS) orelse
				    eq_set_string (s,sort    )
				 then TFree(distinct_name v,sort)
				 else error ("Additional constraint on rhs "^
					     "for type variable "^quote v))
	(** BUG OR FEATURE?: mutual recursion may use different arguments **)
        |   analyse(Type(s,typl)) = (case assoc_string((*dtnvs*)
						       [(dname,typevars)],s) of 
		None          => Type(s,map analyse typl)
	      | Some typevars => if remove_sorts typevars = remove_sorts typl 
				then Type(s,map analyse typl)
				else error ("Recursion of type " ^ s ^ 
					    " with different arguments"))
        |   analyse(TVar _) = Imposs "extender:analyse";
	fun check_pcpo t = (pcpo_type sg t orelse error(
			   "Type not of sort pcpo: "^string_of_typ sg t); t);
	val analyse_con = upd_third (map (upd_third (check_pcpo o analyse)));
      in ((dname,distinct_typevars), map analyse_con cons') end; 
  in ListPair.map analyse_equation (dtnvs,cons'')
  end; (* let *)

(* ----- calls for building new thy and thms -------------------------------- *)

in

  fun add_domain (comp_dnam,eqs''') thy''' = let
    val sg''' = sign_of thy''';
    val dtnvs = map ((fn (dname,vs) => 
			 (Sign.full_name sg''' dname,map (str2typ sg''') vs))
                   o fst) eqs''';
    val cons''' = map snd eqs''';
    fun thy_type  (dname,tvars)  = (Sign.base_name dname, length tvars, NoSyn);
    fun thy_arity (dname,tvars)  = (dname, map (snd o rep_TFree) tvars, pcpoS);
    val thy'' = thy''' |> Theory.add_types     (map thy_type  dtnvs)
		       |> Theory.add_arities_i (map thy_arity dtnvs);
    val sg'' = sign_of thy'';
    val cons''=map (map (upd_third (map (upd_third (str2typ sg''))))) cons''';
    val eqs' = check_and_sort_domain (dtnvs,cons'') sg'';
    val thy' = thy'' |> Domain_Syntax.add_syntax (comp_dnam,eqs');
    val dts  = map (Type o fst) eqs';
    fun strip ss = drop (find_index_eq "'" ss +1, ss);
    fun typid (Type  (id,_)) =
          let val c = hd (Symbol.explode (Sign.base_name id))
          in if Symbol.is_letter c then c else "t" end
      | typid (TFree (id,_)   ) = hd (strip (tl (Symbol.explode id)))
      | typid (TVar ((id,_),_)) = hd (tl (Symbol.explode id));
    fun cons cons' = (map (fn (con,syn,args) =>
	((Syntax.const_name con syn),
	 ListPair.map (fn ((lazy,sel,tp),vn) => ((lazy,
					find_index_eq tp dts),
					sel,vn))
	     (args,(mk_var_names(map (typid o third) args)))
	 )) cons') : cons list;
    val eqs = map (fn (dtnvs,cons') => (dtnvs,cons cons')) eqs' : eq list;
    val thy        = thy' |> Domain_Axioms.add_axioms (comp_dnam,eqs);
  in (foldl (fn (thy0,eq) => Domain_Theorems.theorems (eq,eqs) thy0) (thy,eqs)) 
                          |> Domain_Theorems.comp_theorems (comp_dnam, eqs) end;

end (* local *)
end (* struct *)