--- a/Nominal-General/nominal_eqvt.ML	Wed May 12 13:43:48 2010 +0100
+++ b/Nominal-General/nominal_eqvt.ML	Wed May 12 14:47:52 2010 +0100
@@ -7,9 +7,11 @@
 
 signature NOMINAL_EQVT =
 sig
-  val equivariance: string -> Proof.context -> local_theory
   val eqvt_rel_tac: Proof.context -> string list -> term -> thm -> thm list -> int -> tactic
   val eqvt_rel_single_case_tac: Proof.context -> string list -> term -> thm -> int -> tactic
+  
+  val equivariance: term list -> thm -> thm list -> Proof.context -> (string * thm list) list * local_theory
+  val equivariance_cmd: string -> Proof.context -> local_theory
 end
 
 structure Nominal_Eqvt : NOMINAL_EQVT =
@@ -127,12 +129,11 @@
 (* sets up goal and makes sure parameters
    are untouched PROBLEM: this violates the 
    form of eqvt lemmas *)
-fun prepare_goal params_no pi pred =
+fun prepare_goal pi pred =
 let
   val (c, xs) = strip_comb pred;
-  val (xs1, xs2) = chop params_no xs
 in
-  HOLogic.mk_imp (pred, list_comb (c, xs1 @ map (mk_perm pi) xs2))
+  HOLogic.mk_imp (pred, list_comb (c, map (mk_perm pi) xs))
 end
 
 (* stores thm under name.eqvt and adds [eqvt]-attribute *)
@@ -145,38 +146,43 @@
   Local_Theory.note ((thm_name, [attr]), [thm]) ctxt
 end
 
-fun equivariance pred_name ctxt = 
+fun equivariance pred_trms raw_induct intrs ctxt = 
 let
-  val thy = ProofContext.theory_of ctxt
-  val ({names, ...}, {raw_induct, intrs, ...}) =
-    Inductive.the_inductive ctxt (Sign.intern_const thy pred_name)
-  val raw_induct = atomize_induct ctxt raw_induct
-  val intros = map atomize_intr intrs
-  val params_no = length (Inductive.params_of raw_induct)
+  val pred_names = map (fst o dest_Const) pred_trms
+  val raw_induct' = atomize_induct ctxt raw_induct
+  val intrs' = map atomize_intr intrs
   val (([raw_concl], [raw_pi]), ctxt') = 
     ctxt 
-    |> Variable.import_terms false [concl_of raw_induct] 
+    |> Variable.import_terms false [concl_of raw_induct'] 
     ||>> Variable.variant_fixes ["p"]
   val pi = Free (raw_pi, @{typ perm})
   val preds = map (fst o HOLogic.dest_imp)
     (HOLogic.dest_conj (HOLogic.dest_Trueprop raw_concl));
   val goal = HOLogic.mk_Trueprop 
-    (foldr1 HOLogic.mk_conj (map (prepare_goal params_no pi) preds))
+    (foldr1 HOLogic.mk_conj (map (prepare_goal pi) preds))
   val thms = Datatype_Aux.split_conj_thm (Goal.prove ctxt' [] [] goal 
-    (fn {context,...} => eqvt_rel_tac context names pi raw_induct intros 1)
+    (fn {context,...} => eqvt_rel_tac context pred_names pi raw_induct' intrs' 1)
     |> singleton (ProofContext.export ctxt' ctxt))
   val thms' = map (fn th => zero_var_indexes (th RS mp)) thms
 in
-  ctxt |> fold_map note_named_thm (names ~~ thms') |> snd  
+  ctxt |> fold_map note_named_thm (pred_names ~~ thms')   
 end
 
+fun equivariance_cmd pred_name ctxt =
+let
+  val thy = ProofContext.theory_of ctxt
+  val (_, {preds, raw_induct, intrs, ...}) =
+    Inductive.the_inductive ctxt (Sign.intern_const thy pred_name)
+in
+  equivariance preds raw_induct intrs ctxt |> snd
+end
 
 local structure P = OuterParse and K = OuterKeyword in
 
 val _ =
   OuterSyntax.local_theory "equivariance"
     "Proves equivariance for inductive predicate involving nominal datatypes." 
-      K.thy_decl (P.xname >> equivariance);
+      K.thy_decl (P.xname >> equivariance_cmd);
 end;
 
 end (* structure *)