+
+module TC = CicTypeChecker
+module UM = UriManager
+module R = CicReduction
+module C = Cic
+module PEH = ProofEngineHelpers
+module PER = ProofEngineReduction
+module MS = CicMetaSubst
+module S = CicSubstitution
+module T = Tacticals
+module RT = ReductionTactics
+
+let rec args_init n f =
+ if n <= 0 then [] else f n :: args_init (pred n) f
+
+let mk_predicate_for_elim
+ ~context ~metasenv ~ugraph ~goal ~arg ~using ~cpattern ~args_no =
+ let instantiated_eliminator =
+ let f n = if n = 1 then arg else C.Implicit None in
+ C.Appl (using :: args_init args_no f)
+ in
+ let _actual_arg, iety, _metasenv', _ugraph =
+ CicRefine.type_of_aux' metasenv context instantiated_eliminator ugraph
+ in
+ let _actual_meta, actual_args = match iety with
+ | C.Meta (i, _) -> i, []
+ | C.Appl (C.Meta (i, _) :: args) -> i, args
+ | _ -> assert false
+ in
+(* let _, upto = PEH.split_with_whd (List.nth splits pred_pos) in *)
+ let rec mk_pred metasenv context' pred arg' cpattern' = function
+ | [] -> metasenv, pred, arg'
+ | arg :: tail ->
+(* FG: we find the predicate for the eliminator as in the rewrite tactic ****)
+ let argty, _ugraph = TC.type_of_aux' metasenv context arg ugraph in
+ let argty = CicReduction.whd context argty in
+ let fresh_name =
+ FreshNamesGenerator.mk_fresh_name
+ ~subst:[] metasenv context' C.Anonymous ~typ:argty
+ in
+ let hyp = Some (fresh_name, C.Decl argty) in
+ let lazy_term c m u =
+ let distance = List.length c - List.length context in
+ S.lift distance arg, m, u
+ in
+ let pattern = Some lazy_term, [], Some cpattern' in
+ let subst, metasenv, _ugraph, _conjecture, selected_terms =
+ ProofEngineHelpers.select
+ ~metasenv ~ugraph ~conjecture:(0, context, pred) ~pattern
+ in
+ let metasenv = MS.apply_subst_metasenv subst metasenv in
+ let map (_context_of_t, t) l = t :: l in
+ let what = List.fold_right map selected_terms [] in
+ let arg' = MS.apply_subst subst arg' in
+ let argty = MS.apply_subst subst argty in
+ let pred = PER.replace_with_rel_1_from ~equality:(==) ~what 1 pred in
+ let pred = MS.apply_subst subst pred in
+ let pred = C.Lambda (fresh_name, argty, pred) in
+ let cpattern' = C.Lambda (C.Anonymous, C.Implicit None, cpattern') in
+ mk_pred metasenv (hyp :: context') pred arg' cpattern' tail
+ in
+ let metasenv, pred, arg =
+ mk_pred metasenv context goal arg cpattern (List.rev actual_args)
+ in
+ HLog.debug ("PREDICATE: " ^ CicPp.ppterm ~metasenv pred ^ " ARGS: " ^ String.concat " " (List.map (CicPp.ppterm ~metasenv) actual_args));
+ metasenv, pred, arg, actual_args
+
+let beta_after_elim_tac upto predicate =
+ let beta_after_elim_tac status =
+ let proof, goal = status in
+ let _, metasenv, _subst, _, _, _ = proof in
+ let _, _, ty = CicUtil.lookup_meta goal metasenv in
+ let mk_pattern ~equality ~upto ~predicate ty =
+ (* code adapted from ProceduralConversion.generalize *)
+ let meta = C.Implicit None in
+ let hole = C.Implicit (Some `Hole) in
+ let anon = C.Anonymous in
+ let is_meta =
+ let map b = function
+ | C.Implicit None when b -> b
+ | _ -> false
+ in
+ List.fold_left map true
+ in
+ let rec gen_fix len k (name, i, ty, bo) =
+ name, i, gen_term k ty, gen_term (k + len) bo
+ and gen_cofix len k (name, ty, bo) =
+ name, gen_term k ty, gen_term (k + len) bo
+ and gen_term k = function
+ | C.Sort _
+ | C.Implicit _
+ | C.Const (_, _)
+ | C.Var (_, _)
+ | C.MutInd (_, _, _)
+ | C.MutConstruct (_, _, _, _)
+ | C.Meta (_, _)
+ | C.Rel _ -> meta
+ | C.Appl (hd :: tl) when equality hd (S.lift k predicate) ->
+ assert (List.length tl = upto);
+ hole
+ | C.Appl ts ->
+ let ts = List.map (gen_term k) ts in
+ if is_meta ts then meta else C.Appl ts
+ | C.Cast (te, ty) ->
+ let te, ty = gen_term k te, gen_term k ty in
+ if is_meta [te; ty] then meta else C.Cast (te, ty)
+ | C.MutCase (sp, i, outty, t, pl) ->
+ let outty, t, pl = gen_term k outty, gen_term k t, List.map (gen_term k) pl in
+ if is_meta (outty :: t :: pl) then meta else hole (* C.MutCase (sp, i, outty, t, pl) *)
+ | C.Prod (_, s, t) ->
+ let s, t = gen_term k s, gen_term (succ k) t in
+ if is_meta [s; t] then meta else C.Prod (anon, s, t)
+ | C.Lambda (_, s, t) ->
+ let s, t = gen_term k s, gen_term (succ k) t in
+ if is_meta [s; t] then meta else C.Lambda (anon, s, t)
+ | C.LetIn (_, s, ty, t) ->
+ let s,ty,t = gen_term k s, gen_term k ty, gen_term (succ k) t in
+ if is_meta [s; t] then meta else C.LetIn (anon, s, ty, t)
+ | C.Fix (i, fl) -> C.Fix (i, List.map (gen_fix (List.length fl) k) fl)
+ | C.CoFix (i, fl) -> C.CoFix (i, List.map (gen_cofix (List.length fl) k) fl)
+ in
+ None, [], Some (gen_term 0 ty)
+ in
+ let equality = CicUtil.alpha_equivalence in
+ let pattern = mk_pattern ~equality ~upto ~predicate ty in
+ let tactic = RT.head_beta_reduce_tac ~delta:false ~upto ~pattern in
+ PET.apply_tactic tactic status
+ in
+ PET.mk_tactic beta_after_elim_tac
+
+let elim_tac ?using ?(pattern = PET.conclusion_pattern None) term =