1 (* Copyright (C) 2004, HELM Team.
3 * This file is part of HELM, an Hypertextual, Electronic
4 * Library of Mathematics, developed at the Computer Science
5 * Department, University of Bologna, Italy.
7 * HELM is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version 2
10 * of the License, or (at your option) any later version.
12 * HELM is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with HELM; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
22 * For details, see the HELM World-Wide-Web page,
23 * http://helm.cs.unibo.it/
26 exception AssertFailure of string
27 exception MetaSubstFailure of string
29 (* The entry (i,t) in a substitution means that *)
30 (* (META i) have been instantiated with t. *)
31 type substitution = (int * Cic.term) list
34 int -> substitution -> Cic.context -> Cic.metasenv -> (Cic.term option) list -> Cic.term ->
35 Cic.term * Cic.metasenv
37 (* unwind_subst metasenv subst *)
38 (* unwinds [subst] w.r.t. itself. *)
39 (* It can restrict some metavariable in the [metasenv] *)
40 val unwind_subst : Cic.metasenv -> substitution -> substitution * Cic.metasenv
42 (* apply_subst subst t *)
43 (* applies the substitution [subst] to [t] *)
44 (* [subst] must be already unwinded *)
45 val apply_subst : substitution -> Cic.term -> Cic.term
47 (* apply_subst_reducing subst (Some (mtr,reductions_no)) t *)
48 (* performs as (apply_subst subst t) until it finds an application of *)
49 (* (META [mtr]) that, once unwinding is performed, creates a new *)
50 (* beta-redex; in this case up to [reductions_no] consecutive *)
51 (* beta-reductions are performed. *)
52 (* Hint: this function is usually called when [reductions_no] *)
53 (* eta-expansions have been performed and the head of the new *)
54 (* application has been unified with (META [meta_to_reduce]): *)
55 (* during the unwinding the eta-expansions are undone. *)
56 (* [subst] must be already unwinded *)
57 val apply_subst_reducing :
58 substitution -> (int * int) option -> Cic.term -> Cic.term
60 val apply_subst_context : substitution -> Cic.context -> Cic.context
62 (** {2 Pretty printers} *)
64 val ppcontext: ?sep: string -> substitution -> Cic.context -> string
65 val ppmetasenv: ?sep: string -> substitution -> Cic.metasenv -> string
66 val ppsubst: substitution -> string
68 (* {2 Kernel wrappers}
69 * From now on we recreate a kernel abstraction where substitutions are part of
72 val lift : Cic.metasenv -> substitution -> int -> Cic.term -> Cic.term
74 val whd: Cic.metasenv -> substitution -> Cic.context -> Cic.term -> Cic.term
77 Cic.metasenv -> substitution -> Cic.context -> Cic.term -> Cic.term ->
81 Cic.metasenv -> substitution -> Cic.context -> Cic.term ->