src/HOL/Codatatype/Tools/bnf_fp_sugar.ML

--- a/src/HOL/Codatatype/Tools/bnf_fp_sugar.ML	Tue Sep 04 13:02:31 2012 +0200
+++ b/src/HOL/Codatatype/Tools/bnf_fp_sugar.ML	Tue Sep 04 13:02:32 2012 +0200
@@ -12,28 +12,115 @@
 structure BNF_FP_Sugar : BNF_FP_SUGAR =
 struct
 
-fun data_cmd gfp specs lthy =
+open BNF_Util
+open BNF_Wrap
+open BNF_FP_Util
+open BNF_LFP
+open BNF_GFP
+
+fun cannot_merge_types () = error "Mutually recursive (co)datatypes must have same type parameters";
+
+fun merge_type_arg_constrained ctxt (T, c) (T', c') =
+  if T = T' then
+    (case (c, c') of
+      (_, NONE) => (T, c)
+    | (NONE, _) => (T, c')
+    | _ =>
+      if c = c' then
+        (T, c)
+      else
+        error ("Inconsistent sort constraints for type variable " ^
+          quote (Syntax.string_of_typ ctxt T)))
+  else
+    cannot_merge_types ();
+
+fun merge_type_args_constrained ctxt (cAs, cAs') =
+  if length cAs = length cAs' then map2 (merge_type_arg_constrained ctxt) cAs cAs'
+  else cannot_merge_types ();
+
+fun type_args_constrained_of_spec (((cAs, _), _), _) = cAs;
+fun type_name_of_spec (((_, b), _), _) = b;
+fun mixfix_of_spec ((_, mx), _) = mx;
+fun ctr_specs_of_spec (_, ctr_specs) = ctr_specs;
+
+fun disc_of_ctr_spec (((disc, _), _), _) = disc;
+fun ctr_of_ctr_spec (((_, ctr), _), _) = ctr;
+fun args_of_ctr_spec ((_, args), _) = args;
+fun mixfix_of_ctr_spec (_, mx) = mx;
+
+val mk_prod_sum = mk_sumTN o map HOLogic.mk_tupleT;
+
+val lfp_info = bnf_lfp;
+val gfp_info = bnf_gfp;
+
+fun prepare_data prepare_typ construct specs lthy =
   let
+    val constrained_passiveAs =
+      map (map (apfst (prepare_typ lthy)) o type_args_constrained_of_spec) specs
+      |> Library.foldr1 (merge_type_args_constrained lthy);
+    val passiveAs = map fst constrained_passiveAs;
+
+    val _ = (case duplicates (op =) passiveAs of [] => ()
+      | T :: _ => error ("Duplicate type parameter " ^ quote (Syntax.string_of_typ lthy T)));
+
+    (* TODO: check that no type variables occur in the rhss that's not in the lhss *)
+    (* TODO: use sort constraints on type args *)
+
+    val N = length specs;
+
+    val bs = map type_name_of_spec specs;
+    val mixfixes = map mixfix_of_spec specs;
+
+    val _ = (case duplicates Binding.eq_name bs of [] => ()
+      | b :: _ => error ("Duplicate type name declaration " ^ quote (Binding.name_of b)));
+
+    val ctr_specss = map ctr_specs_of_spec specs;
+
+    val disc_namess = map (map disc_of_ctr_spec) ctr_specss;
+    val raw_ctr_namess = map (map ctr_of_ctr_spec) ctr_specss;
+    val ctr_argsss = map (map args_of_ctr_spec) ctr_specss;
+    val ctr_mixfixess = map (map mixfix_of_ctr_spec) ctr_specss;
+
+    val sel_namesss = map (map (map fst)) ctr_argsss;
+    val ctr_Tsss = map (map (map (prepare_typ lthy o snd))) ctr_argsss;
+
+    val (activeAs, _) = lthy |> mk_TFrees N;
+
+    val eqs = map2 (fn TFree A => fn Tss => (A, mk_prod_sum Tss)) activeAs ctr_Tsss;
+
+    val lthy' = fp_bnf construct bs eqs lthy;
+
+    fun wrap_type ((b, disc_names), sel_namess) lthy =
+      let
+        val ctrs = [];
+        val caseof = @{term True};
+        val tacss = [];
+      in
+        wrap tacss ((ctrs, caseof), (disc_names, sel_namess)) lthy
+      end;
   in
-    lthy
+    lthy' |> fold wrap_type (bs ~~ disc_namess ~~ sel_namesss)
   end;
 
+val data_cmd = prepare_data Syntax.read_typ;
+
+val parse_opt_binding_colon = Scan.optional (Parse.binding --| Parse.$$$ ":") no_name
+
 val parse_ctr_arg =
-  Parse.$$$ "(" |-- Scan.option Parse.binding --| Parse.$$$ ":" -- Parse.typ --| Parse.$$$ ")" ||
-  (Parse.typ >> pair NONE);
+  Parse.$$$ "(" |-- parse_opt_binding_colon -- Parse.typ --| Parse.$$$ ")" ||
+  (Parse.typ >> pair no_name);
 
 val parse_single_spec =
   Parse.type_args_constrained -- Parse.binding -- Parse.opt_mixfix --
-  (@{keyword "="} |-- Parse.enum1 "|" (Parse.binding -- Scan.repeat parse_ctr_arg --
-     Parse.opt_mixfix))
-  >> (fn (((vs, t), mx), cons) => ((t, vs, mx), map Parse.triple1 cons));
+  (@{keyword "="} |-- Parse.enum1 "|" (parse_opt_binding_colon -- Parse.binding --
+    Scan.repeat parse_ctr_arg -- Parse.opt_mixfix));
 
 val _ =
   Outer_Syntax.local_theory @{command_spec "data"} "define BNF-based inductive datatypes"
-    (Parse.and_list1 parse_single_spec >> data_cmd false);
+    (Parse.and_list1 parse_single_spec >> data_cmd lfp_info);
 
 val _ =
   Outer_Syntax.local_theory @{command_spec "codata"} "define BNF-based coinductive datatypes"
-    (Parse.and_list1 parse_single_spec >> data_cmd true);
+    (Parse.and_list1 parse_single_spec >> data_cmd gfp_info);
 
 end;