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-rw-r--r--kernel/vars.ml21
-rw-r--r--kernel/vars.mli70
2 files changed, 60 insertions, 31 deletions
diff --git a/kernel/vars.ml b/kernel/vars.ml
index a800e2531..f8c0a65e6 100644
--- a/kernel/vars.ml
+++ b/kernel/vars.ml
@@ -151,6 +151,11 @@ let make_subst = function
done;
subst
+(* The type of substitutions, with term substituting most recent
+ binder at the head *)
+
+type substl = Constr.t list
+
let substnl laml n c = substn_many (make_subst laml) n c
let substl laml c = substn_many (make_subst laml) 0 c
let subst1 lam c = substn_many [|make_substituend lam|] 0 c
@@ -159,13 +164,6 @@ let substnl_decl laml k r = map_rel_declaration (fun c -> substnl laml k c) r
let substl_decl laml r = map_rel_declaration (fun c -> substnl laml 0 c) r
let subst1_decl lam r = map_rel_declaration (fun c -> subst1 lam c) r
-let substnl_named_decl laml k d =
- map_named_declaration (fun c -> substnl laml k c) d
-let substl_named_decl laml d =
- map_named_declaration (fun c -> substnl laml 0 c) d
-let subst1_named_decl lam d =
- map_named_declaration (fun c -> subst1 lam c) d
-
(* (thin_val sigma) removes identity substitutions from sigma *)
let rec thin_val = function
@@ -197,15 +195,10 @@ let replace_vars var_alist x =
in
substrec 0 x
-(*
-let repvarkey = Profile.declare_profile "replace_vars";;
-let replace_vars vl c = Profile.profile2 repvarkey replace_vars vl c ;;
-*)
-
-(* (subst_var str t) substitute (VAR str) by (Rel 1) in t *)
+(* (subst_var str t) substitute (Var str) by (Rel 1) in t *)
let subst_var str t = replace_vars [(str, Constr.mkRel 1)] t
-(* (subst_vars [id1;...;idn] t) substitute (VAR idj) by (Rel j) in t *)
+(* (subst_vars [id1;...;idn] t) substitute (Var idj) by (Rel j) in t *)
let substn_vars p vars c =
let _,subst =
List.fold_left (fun (n,l) var -> ((n+1),(var,Constr.mkRel n)::l)) (p,[]) vars
diff --git a/kernel/vars.mli b/kernel/vars.mli
index c0fbeeb6e..ab10ba93b 100644
--- a/kernel/vars.mli
+++ b/kernel/vars.mli
@@ -42,33 +42,69 @@ val liftn : int -> int -> constr -> constr
(** [lift n c] lifts by [n] the positive indexes in [c] *)
val lift : int -> constr -> constr
-(** [substnl [a1;...;an] k c] substitutes in parallel [a1],...,[an]
+(** The type [substl] is the type of substitutions [u₁..un] of type
+ some context Δ and defined in some environment Γ. Typing of
+ substitutions is defined by:
+ - Γ ⊢ ∅ : ∅,
+ - Γ ⊢ u₁..u{_n-1} : Δ and Γ ⊢ u{_n} : An\[u₁..u{_n-1}\] implies
+ Γ ⊢ u₁..u{_n} : Δ,x{_n}:A{_n}
+ - Γ ⊢ u₁..u{_n-1} : Δ and Γ ⊢ un : A{_n}\[u₁..u{_n-1}\] implies
+ Γ ⊢ u₁..u{_n} : Δ,x{_n}:=c{_n}:A{_n} when Γ ⊢ u{_n} ≡ c{_n}\[u₁..u{_n-1}\]
+
+ Note that [u₁..un] is represented as a list with [un] at the head of
+ the list, i.e. as [[un;...;u₁]]. *)
+
+type substl = constr list
+
+(** [substnl [a₁;...;an] k c] substitutes in parallel [a₁],...,[an]
for respectively [Rel(k+1)],...,[Rel(k+n)] in [c]; it relocates
- accordingly indexes in [a1],...,[an] and [c] *)
-val substnl : constr list -> int -> constr -> constr
-val substl : constr list -> constr -> constr
+ accordingly indexes in [an],...,[a1] and [c]. In terms of typing, if
+ Γ ⊢ a{_n}..a₁ : Δ and Γ, Δ, Γ' ⊢ c : T with |Γ'|=k, then
+ Γ, Γ' ⊢ [substnl [a₁;...;an] k c] : [substnl [a₁;...;an] k T]. *)
+val substnl : substl -> int -> constr -> constr
+
+(** [substl σ c] is a short-hand for [substnl σ 0 c] *)
+val substl : substl -> constr -> constr
+
+(** [substl a c] is a short-hand for [substnl [a] 0 c] *)
val subst1 : constr -> constr -> constr
-val substnl_decl : constr list -> int -> rel_declaration -> rel_declaration
-val substl_decl : constr list -> rel_declaration -> rel_declaration
-val subst1_decl : constr -> rel_declaration -> rel_declaration
+(** [substnl_decl [a₁;...;an] k Ω] substitutes in parallel [a₁], ..., [an]
+ for respectively [Rel(k+1)], ..., [Rel(k+n)] in [Ω]; it relocates
+ accordingly indexes in [a₁],...,[an] and [c]. In terms of typing, if
+ Γ ⊢ a{_n}..a₁ : Δ and Γ, Δ, Γ', Ω ⊢ with |Γ'|=[k], then
+ Γ, Γ', [substnl_decl [a₁;...;an]] k Ω ⊢. *)
+val substnl_decl : substl -> int -> rel_declaration -> rel_declaration
+
+(** [substl_decl σ Ω] is a short-hand for [substnl_decl σ 0 Ω] *)
+val substl_decl : substl -> rel_declaration -> rel_declaration
-val substnl_named_decl : constr list -> int -> named_declaration -> named_declaration
-val subst1_named_decl : constr -> named_declaration -> named_declaration
-val substl_named_decl : constr list -> named_declaration -> named_declaration
+(** [subst1_decl a Ω] is a short-hand for [substnl_decl [a] 0 Ω] *)
+val subst1_decl : constr -> rel_declaration -> rel_declaration
+(** [replace_vars k [(id₁,c₁);...;(idn,cn)] t] substitutes [Var idj] by
+ [cj] in [t]. *)
val replace_vars : (Id.t * constr) list -> constr -> constr
-(** (subst_var str t) substitute (VAR str) by (Rel 1) in t *)
-val subst_var : Id.t -> constr -> constr
-(** [subst_vars [id1;...;idn] t] substitute [VAR idj] by [Rel j] in [t]
- if two names are identical, the one of least indice is kept *)
-val subst_vars : Id.t list -> constr -> constr
+(** [substn_vars k [id₁;...;idn] t] substitutes [Var idj] by [Rel j+k-1] in [t].
+ If two names are identical, the one of least index is kept. In terms of
+ typing, if Γ,x{_n}:U{_n},...,x₁:U₁,Γ' ⊢ t:T, together with id{_j}:T{_j} and
+ Γ,x{_n}:U{_n},...,x₁:U₁,Γ' ⊢ T{_j}\[id{_j+1}..id{_n}:=x{_j+1}..x{_n}\] ≡ Uj,
+ then Γ\\{id₁,...,id{_n}\},x{_n}:U{_n},...,x₁:U₁,Γ' ⊢ [substn_vars
+ (|Γ'|+1) [id₁;...;idn] t] : [substn_vars (|Γ'|+1) [id₁;...;idn]
+ T]. *)
-(** [substn_vars n [id1;...;idn] t] substitute [VAR idj] by [Rel j+n-1] in [t]
- if two names are identical, the one of least indice is kept *)
val substn_vars : int -> Id.t list -> constr -> constr
+(** [subst_vars [id1;...;idn] t] is a short-hand for [substn_vars
+ [id1;...;idn] 1 t]: it substitutes [Var idj] by [Rel j] in [t]. If
+ two names are identical, the one of least index is kept. *)
+val subst_vars : Id.t list -> constr -> constr
+
+(** [subst_var id t] is a short-hand for [substn_vars [id] 1 t]: it
+ substitutes [Var id] by [Rel 1] in [t]. *)
+val subst_var : Id.t -> constr -> constr
+
(** {3 Substitution of universes} *)
open Univ