--- a/src/HOL/Nominal/Nominal.thy Wed Apr 18 21:30:14 2007 +0200
+++ b/src/HOL/Nominal/Nominal.thy Thu Apr 19 16:27:53 2007 +0200
@@ -3203,6 +3203,10 @@
(* various tactics for analysing permutations, supports etc *)
use "nominal_permeq.ML";
+(****************************************************************)
+(* tactics for generating fresh names and simplifying fresh_fun *)
+use "nominal_fresh_fun.ML";
+
method_setup perm_simp =
{* NominalPermeq.perm_simp_meth *}
{* simp rules and simprocs for analysing permutations *}
@@ -3243,6 +3247,16 @@
{* NominalPermeq.fresh_guess_meth_debug *}
{* tactic for deciding whether an atom is fresh for something including debugging facilities *}
+
+method_setup generate_fresh =
+ {* setup_generate_fresh *}
+ {* tactic to generate a name fresh for all the variables in the goal *}
+
+method_setup fresh_fun_simp =
+ {* setup_fresh_fun_simp *}
+ {* tactic to delete one inner occurence of fresh_fun *}
+
+
(************************************************)
(* main file for constructing nominal datatypes *)
use "nominal_package.ML"
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/Nominal/nominal_fresh_fun.ML Thu Apr 19 16:27:53 2007 +0200
@@ -0,0 +1,154 @@
+(* Title: HOL/Nominal/nominal_fresh_fun.ML
+ ID: $Id$
+ Authors: Stefan Berghofer, Julien Narboux, TU Muenchen
+
+A tactic to generate fresh names.
+A tactic to get rid of the fresh_fun.
+*)
+
+(* First some functions that could be
+ in the library *)
+
+fun gen_res_inst_tac_term instf tyinst tinst elim th i st =
+ let
+ val thy = theory_of_thm st;
+ val cgoal = nth (cprems_of st) (i - 1);
+ val {maxidx, ...} = rep_cterm cgoal;
+ val j = maxidx + 1;
+ val tyinst' = map (apfst (Logic.incr_tvar j)) tyinst;
+ val ps = Logic.strip_params (term_of cgoal);
+ val Ts = map snd ps;
+ val tinst' = map (fn (t, u) =>
+ (head_of (Logic.incr_indexes (Ts, j) t),
+ list_abs (ps, u))) tinst;
+ val th' = instf
+ (map (pairself (ctyp_of thy)) tyinst')
+ (map (pairself (cterm_of thy)) tinst')
+ (Thm.lift_rule cgoal th)
+ in
+ compose_tac (elim, th', nprems_of th) i st
+ end handle Subscript => Seq.empty;
+
+val res_inst_tac_term =
+ gen_res_inst_tac_term (curry Thm.instantiate);
+
+val res_inst_tac_term' =
+ gen_res_inst_tac_term (K Drule.cterm_instantiate) [];
+
+fun cut_inst_tac_term' tinst th =
+ res_inst_tac_term' tinst false (Tactic.make_elim_preserve th);
+
+fun get_dyn_thm thy name atom_name = (PureThy.get_thm thy (Name name)) handle _ => raise ERROR ("The atom type "^atom_name^" is not defined.");
+
+(* End of function waiting to be
+ in the library *)
+
+(* The theorems needed that are known at
+compile time. *)
+
+val at_exists_fresh' = thm "at_exists_fresh'";
+val fresh_fun_app = thm "fresh_fun_app";
+val fresh_prod = thm "fresh_prod";
+
+(* A tactic to generate a name fresh for
+all the free variables and parameters of the goal *)
+
+fun generate_fresh_tac atom_name i thm =
+ let
+ val thy = theory_of_thm thm;
+(* the parsing function returns a qualified name, we get back the base name *)
+ val atom_basename = Sign.base_name atom_name;
+ val goal = List.nth(prems_of thm, i-1);
+ val ps = Logic.strip_params goal;
+ val Ts = rev (map snd ps);
+ fun is_of_fs_name T = Type.of_sort (Sign.tsig_of thy)
+ (T, Sign.intern_sort thy ["fs_"^atom_basename]);
+(* rebuild de bruijn indices *)
+ val bvs = map_index (Bound o fst) ps;
+(* select variables of the right class *)
+ val vs = filter (fn t => is_of_fs_name (fastype_of1 (Ts, t)))
+ (term_frees goal @ bvs);
+(* build the tuple *)
+ val s = Library.foldr1 (fn (v, s) =>
+ HOLogic.pair_const (fastype_of1 (Ts, v)) (fastype_of1 (Ts, s)) $ v $ s)
+ vs;
+ val fs_name_thm = get_dyn_thm thy ("fs_"^atom_basename^"1") atom_basename;
+ val at_name_inst_thm = get_dyn_thm thy ("at_"^atom_basename^"_inst") atom_basename;
+ val exists_fresh' = at_name_inst_thm RS at_exists_fresh';
+(* find the variable we want to instantiate *)
+ val x = hd (term_vars (prop_of exists_fresh'));
+ in
+ (cut_inst_tac_term' [(x,s)] exists_fresh' 1 THEN
+ rtac fs_name_thm 1 THEN
+ etac exE 1) thm
+ handle Empty => all_tac thm (* if we collected no variables then we do nothing *)
+ end;
+
+fun get_inner_fresh_fun (Bound j) = NONE
+ | get_inner_fresh_fun (v as Free _) = NONE
+ | get_inner_fresh_fun (v as Var _) = NONE
+ | get_inner_fresh_fun (Const _) = NONE
+ | get_inner_fresh_fun (Abs (_, _, t)) = get_inner_fresh_fun t
+ | get_inner_fresh_fun (Const ("Nominal.fresh_fun",Type("fun",[Type ("fun",[Type (T,_),_]),_])) $ u) = SOME T
+ | get_inner_fresh_fun (t $ u) =
+ let val a = get_inner_fresh_fun u in
+ if a = NONE then get_inner_fresh_fun t else a
+ end;
+
+(* This tactic generates a fresh name
+of the atom type given by the inner most fresh_fun *)
+
+fun generate_fresh_fun_tac i thm =
+ let
+ val goal = List.nth(prems_of thm, i-1);
+ val atom_name_opt = get_inner_fresh_fun goal;
+ in
+ case atom_name_opt of
+ NONE => all_tac thm
+ | SOME atom_name => generate_fresh_tac atom_name i thm
+ end
+
+(* A substitution tactic, FIXME : change the search function to get the inner occurence of fresh_fun (bottom -> up search ) *)
+
+fun subst_outer_tac ctx = EqSubst.eqsubst_tac' ctx (curry (Seq.flat o (uncurry EqSubst.searchf_lr_unify_valid)));
+
+fun fresh_fun_tac i thm =
+ (* Find the variable we instantiate *)
+ let
+ val thy = theory_of_thm thm;
+ val ctx = Context.init_proof thy;
+ val ss = simpset_of thy;
+ val abs_fresh = PureThy.get_thms thy (Name "abs_fresh");
+ val ss' = ss addsimps fresh_prod::abs_fresh;
+ val x = hd (tl (term_vars (prop_of exI)));
+ val goal = List.nth(prems_of thm, i-1);
+ val atom_name_opt = get_inner_fresh_fun goal;
+ val n = List.length (Logic.strip_params goal);
+ (* Here we rely on the fact that the variable introduced by generate_fresh_tac is the last one in the list, the inner one *)
+ in
+ case atom_name_opt of
+ NONE => all_tac thm
+ | SOME atom_name =>
+ let
+ val atom_basename = Sign.base_name atom_name;
+ val pt_name_inst = get_dyn_thm thy ("pt_"^atom_basename^"_inst") atom_basename;
+ val at_name_inst = get_dyn_thm thy ("at_"^atom_basename^"_inst") atom_basename;
+ in
+ (generate_fresh_tac atom_name i THEN
+ subst_outer_tac ctx fresh_fun_app i THEN
+ rtac pt_name_inst i THEN
+ rtac at_name_inst i THEN
+ NominalPermeq.finite_guess_tac HOL_ss i THEN
+ auto_tac (HOL_cs , HOL_ss) THEN
+ NominalPermeq.fresh_guess_tac HOL_ss (i+1) THEN
+ res_inst_tac_term' [(x,Bound n)] false exI i THEN
+ asm_full_simp_tac ss' i THEN
+ NominalPermeq.fresh_guess_tac HOL_ss i) thm
+ end
+ end
+
+val setup_generate_fresh =
+ Method.goal_args_ctxt' Args.tyname (fn ctxt => generate_fresh_tac)
+
+val setup_fresh_fun_simp =
+ Method.no_args (Method.SIMPLE_METHOD (fresh_fun_tac 1))