--- /dev/null
+(* Copyright (C) 2000, HELM Team.
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+(* $Id$ *)
+
+let debug_print = fun _ -> ();;
+
+(* to be moved in cic util *)
+let expand_local_context = function
+ | NCic.Irl len ->
+ let rec aux acc = function
+ | 0 -> acc
+ | n -> aux (NCic.Rel n::acc) (n-1)
+ in
+ aux [] len
+ | NCic.Ctx lctx -> lctx
+;;
+
+let lift_from k n =
+ let rec liftaux k = function
+ | NCic.Const _
+ | NCic.Sort _ as t -> t
+ | NCic.Rel m ->
+ if m < k then NCic.Rel m
+ else NCic.Rel (m + n)
+ | NCic.Meta (i,(m,l)) when k <= m -> NCic.Meta (i,(m+n,l))
+ | NCic.Meta (_,(m,NCic.Irl l)) as t when k > l + m -> t
+ | NCic.Meta (i,(m,l)) ->
+ let lctx = expand_local_context l in
+ NCic.Meta (i, (m, NCic.Ctx (List.map (liftaux (k-m)) lctx)))
+ | NCic.Implicit _ -> (* was the identity *) assert false
+ | NCic.Prod (n,s,t) -> NCic.Prod (n, liftaux k s, liftaux (k+1) t)
+ | NCic.Lambda (n,s,t) -> NCic.Lambda (n, liftaux k s, liftaux (k+1) t)
+ | NCic.LetIn (n,ty,te,t) ->
+ NCic.LetIn (n, liftaux k ty, liftaux k te, liftaux (k+1) t)
+ | NCic.Appl l -> NCic.Appl (List.map (liftaux k) l)
+ | NCic.Match (r,outty,t,pl) ->
+ NCic.Match (r,liftaux k outty,liftaux k t, List.map (liftaux k) pl)
+ in
+ liftaux k
+;;
+
+let lift ?(from=1) n t =
+ if n = 0 then t
+ else lift_from from n t
+;;
+
+(* subst t1 t2 *)
+(* substitutes [t1] for [Rel 1] in [t2] *)
+(* if avoid_beta_redexes is true (default: false) no new beta redexes *)
+(* are generated. WARNING: the substitution can diverge when t2 is not *)
+(* well typed and avoid_beta_redexes is true. *)
+let rec psubst ?(avoid_beta_redexes=false) delift lift_args args =
+ let nargs = List.length args in
+ let rec substaux k = function
+ | NCic.Rel n as t ->
+ (match n with
+ | n when n >= (k+nargs) -> if delift then NCic.Rel (n - nargs) else t
+ | n when n < k -> t
+ | n (* k <= n < k+nargs *) ->
+ (try lift (k+lift_args) (List.nth args (n-k))
+ with Failure _ -> assert false))
+ | NCic.Meta (_,(m,_)) as t when m >= k + nargs - 1 -> t
+ | NCic.Meta (_,(m,NCic.Irl l)) as t when k > l + m -> t
+ | NCic.Meta (i,(m,l)) ->
+ let lctx = expand_local_context l in
+ (* 1-nargs < k-m, when <= 0 is still reasonable because we will
+ * substitute args[ k-m ... k-m+nargs-1 > 0 ] *)
+ NCic.Meta (i,(m, NCic.Ctx (List.map (substaux (k-m)) lctx)))
+ | NCic.Sort _ as t -> t
+ | NCic.Implicit _ -> assert false (* was identity *)
+ | NCic.Prod (n,s,t) -> NCic.Prod (n, substaux k s, substaux (k + 1) t)
+ | NCic.Lambda (n,s,t) -> NCic.Lambda (n, substaux k s, substaux (k + 1) t)
+ | NCic.LetIn (n,ty,te,t) ->
+ NCic.LetIn (n, substaux k ty, substaux k te, substaux (k + 1) t)
+ | NCic.Appl (he::tl) ->
+ (* Invariant: no Appl applied to another Appl *)
+ let rec avoid he = function
+ | [] -> he
+ | arg::tl as args->
+ (match he with
+ | NCic.Appl l -> NCic.Appl (l@args)
+ | NCic.Lambda (_,_,bo) when avoid_beta_redexes ->
+ avoid (psubst ~avoid_beta_redexes true 0 [arg] bo) tl
+ | _ as he -> NCic.Appl (he::args))
+ in
+ let tl = List.map (substaux k) tl in
+ avoid (substaux k he) tl
+ | NCic.Appl _ -> assert false
+ | NCic.Const _ as t -> t
+ | NCic.Match (r,outt,t,pl) ->
+ NCic.Match (r,substaux k outt, substaux k t, List.map (substaux k) pl)
+ in
+ substaux 1
+;;
+
+let subst ?avoid_beta_redexes arg = psubst ?avoid_beta_redexes true 0 [arg];;
+
+(* subst_meta (n, Some [t_1 ; ... ; t_n]) t *)
+(* returns the term [t] where [Rel i] is substituted with [t_i] lifted by n *)
+(* [t_i] is lifted as usual when it crosses an abstraction *)
+(* subst_meta (n, Non) t -> lift n t *)
+let subst_meta = function
+ | m, NCic.Irl _
+ | m, NCic.Ctx [] -> lift m
+ | m, NCic.Ctx l -> psubst false m l
+;;
--- /dev/null
+(* Copyright (C) 2000, HELM Team.
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://cs.unibo.it/helm/.
+ *)
+
+(* lift n t *)
+(* lifts [t] of [n] *)
+(* [from] default 1, lifts only indexes >= [from] *)
+(* NOTE: the opposite function (delift_rels) is defined in CicMetaSubst *)
+(* since it needs to restrict the metavariables in case of failure *)
+val lift : ?from:int -> int -> NCic.term -> NCic.term
+
+(* subst t1 t2 *)
+(* substitutes [t1] for [Rel 1] in [t2] *)
+(* if avoid_beta_redexes is true (default: false) no new beta redexes *)
+(* are generated. WARNING: the substitution can diverge when t2 is not *)
+(* well typed and avoid_beta_redexes is true. *)
+val subst : ?avoid_beta_redexes:bool -> NCic.term -> NCic.term -> NCic.term
+
+(* subst_meta (n, Ctx [t_1 ; ... ; t_n]) t *)
+(* returns the term [t] where [Rel i] is substituted with [t_i] lifted by n *)
+(* [t_i] is lifted as usual when it crosses an abstraction *)
+(* subst_meta (n, Irl _) t -> lift n t *)
+val subst_meta : NCic.local_context -> NCic.term -> NCic.term
+
projects / helm.git / commitdiff