X-Git-Url: http://matita.cs.unibo.it/gitweb/?p=helm.git;a=blobdiff_plain;f=components%2Fcic%2FcicUtil.ml;fp=components%2Fcic%2FcicUtil.ml;h=75b7fd2cc8505390ec0ff96cc203d9744fd5b390;hp=0000000000000000000000000000000000000000;hb=f61af501fb4608cc4fb062a0864c774e677f0d76;hpb=58ae1809c352e71e7b5530dc41e2bfc834e1aef1

diff --git a/components/cic/cicUtil.ml b/components/cic/cicUtil.ml
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+(* Copyright (C) 2004, 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://helm.cs.unibo.it/
+ *)
+
+(* $Id$ *)
+
+module C = Cic
+
+exception Meta_not_found of int
+exception Subst_not_found of int
+
+let lookup_meta index metasenv =
+  try
+    List.find (fun (index', _, _) -> index = index') metasenv
+  with Not_found -> raise (Meta_not_found index)
+
+let lookup_subst n subst =
+  try
+    List.assoc n subst
+  with Not_found -> raise (Subst_not_found n)
+
+let exists_meta index = List.exists (fun (index', _, _) -> (index = index'))
+
+(* clean_up_meta take a substitution, a metasenv a meta_inex and a local
+context l and clean up l with respect to the hidden hipothesis in the 
+canonical context *)
+
+let clean_up_local_context subst metasenv n l =
+  let cc =
+    (try
+       let (cc,_,_) = lookup_subst n subst in cc
+     with Subst_not_found _ ->
+       try
+	 let (_,cc,_) = lookup_meta n metasenv in cc
+       with Meta_not_found _ -> assert false) in
+  (try 
+     List.map2
+       (fun t1 t2 ->
+	  match t1,t2 with 
+	      None , _ -> None
+	    | _ , t -> t) cc l
+   with 
+       Invalid_argument _ -> 
+	 assert false)
+
+let is_closed =
+ let module C = Cic in
+ let rec is_closed k =
+  function
+      C.Rel m when m > k -> false
+    | C.Rel m -> true
+    | C.Meta (_,l) ->
+       List.fold_left
+        (fun i t -> i && (match t with None -> true | Some t -> is_closed k t)
+        ) true l
+    | C.Sort _ -> true
+    | C.Implicit _ -> assert false
+    | C.Cast (te,ty) -> is_closed k te && is_closed k ty
+    | C.Prod (name,so,dest) -> is_closed k so && is_closed (k+1) dest
+    | C.Lambda (_,so,dest) -> is_closed k so && is_closed (k+1) dest
+    | C.LetIn (_,so,ty,dest) ->
+       is_closed k so && is_closed k ty && is_closed (k+1) dest
+    | C.Appl l ->
+       List.fold_right (fun x i -> i && is_closed k x) l true
+    | C.Var (_,exp_named_subst)
+    | C.Const (_,exp_named_subst)
+    | C.MutInd (_,_,exp_named_subst)
+    | C.MutConstruct (_,_,_,exp_named_subst) ->
+       List.fold_right (fun (_,x) i -> i && is_closed k x)
+        exp_named_subst true
+    | C.MutCase (_,_,out,te,pl) ->
+       is_closed k out && is_closed k te &&
+        List.fold_right (fun x i -> i && is_closed k x) pl true
+    | C.Fix (_,fl) ->
+       let len = List.length fl in
+        let k_plus_len = k + len in
+         List.fold_right
+          (fun (_,_,ty,bo) i -> i && is_closed k ty && is_closed k_plus_len bo
+          ) fl true
+    | C.CoFix (_,fl) ->
+       let len = List.length fl in
+        let k_plus_len = k + len in
+         List.fold_right
+          (fun (_,ty,bo) i -> i && is_closed k ty && is_closed k_plus_len bo
+          ) fl true
+in 
+ is_closed 0
+;;
+
+let rec is_meta_closed =
+  function
+      C.Rel _ -> true
+    | C.Meta _ -> false
+    | C.Sort _ -> true
+    | C.Implicit _ -> assert false
+    | C.Cast (te,ty) -> is_meta_closed te && is_meta_closed ty
+    | C.Prod (name,so,dest) -> is_meta_closed so && is_meta_closed dest
+    | C.Lambda (_,so,dest) -> is_meta_closed so && is_meta_closed dest
+    | C.LetIn (_,so,ty,dest) ->
+       is_meta_closed so &&
+       is_meta_closed ty &&
+       is_meta_closed dest
+    | C.Appl l ->
+       not (List.exists (fun x -> not (is_meta_closed x)) l)
+    | C.Var (_,exp_named_subst)
+    | C.Const (_,exp_named_subst)
+    | C.MutInd (_,_,exp_named_subst)
+    | C.MutConstruct (_,_,_,exp_named_subst) ->
+       not (List.exists (fun (_,x) -> not (is_meta_closed x)) exp_named_subst)
+    | C.MutCase (_,_,out,te,pl) ->
+       is_meta_closed out && is_meta_closed te &&
+        not (List.exists (fun x -> not (is_meta_closed x)) pl)
+    | C.Fix (_,fl) ->
+        not (List.exists 
+              (fun (_,_,ty,bo) -> 
+                  not (is_meta_closed ty) || not (is_meta_closed bo)) 
+              fl)
+    | C.CoFix (_,fl) ->
+        not (List.exists 
+              (fun (_,ty,bo) -> 
+                  not (is_meta_closed ty) || not (is_meta_closed bo)) 
+              fl)
+;;
+
+let xpointer_RE = Str.regexp "\\([^#]+\\)#xpointer(\\(.*\\))"
+let slash_RE = Str.regexp "/"
+
+let term_of_uri uri =
+  let s = UriManager.string_of_uri uri in
+  try
+    (if UriManager.uri_is_con uri then
+      C.Const (uri, [])
+    else if UriManager.uri_is_var uri then
+      C.Var (uri, [])
+    else if not (Str.string_match xpointer_RE s 0) then
+      raise (UriManager.IllFormedUri s)
+    else
+      let (baseuri,xpointer) = (Str.matched_group 1 s, Str.matched_group 2 s) in
+      let baseuri = UriManager.uri_of_string baseuri in
+      (match Str.split slash_RE xpointer with
+      | [_; tyno] -> C.MutInd (baseuri, int_of_string tyno - 1, [])
+      | [_; tyno; consno] ->
+          C.MutConstruct
+            (baseuri, int_of_string tyno - 1, int_of_string consno, [])
+      | _ -> raise Exit))
+  with
+  | Exit
+  | Failure _
+  | Not_found -> raise (UriManager.IllFormedUri s)
+
+let uri_of_term = function
+  | C.Const (uri, _)
+  | C.Var (uri, _) -> uri
+  | C.MutInd (baseuri, tyno, _) ->
+     UriManager.uri_of_string
+      (Printf.sprintf "%s#xpointer(1/%d)" (UriManager.string_of_uri baseuri) (tyno+1))
+  | C.MutConstruct (baseuri, tyno, consno, _) ->
+     UriManager.uri_of_string
+      (Printf.sprintf "%s#xpointer(1/%d/%d)" (UriManager.string_of_uri baseuri)
+        (tyno + 1) consno)
+  | _ -> raise (Invalid_argument "uri_of_term")
+
+
+(*
+let pack terms =
+  List.fold_right
+    (fun term acc -> C.Prod (C.Anonymous, term, acc))
+    terms (C.Sort (C.Type (CicUniv.fresh ())))
+
+let rec unpack = function
+  | C.Prod (C.Anonymous, term, C.Sort (C.Type _)) -> [term]
+  | C.Prod (C.Anonymous, term, tgt) -> term :: unpack tgt
+  | _ -> assert false
+*)
+
+let rec strip_prods n = function
+  | t when n = 0 -> t
+  | C.Prod (_, _, tgt) when n > 0 -> strip_prods (n-1) tgt
+  | _ -> failwith "not enough prods"
+
+let params_of_obj = function
+  | C.Constant (_, _, _, params, _)
+  | C.Variable (_, _, _, params, _)
+  | C.CurrentProof (_, _, _, _, params, _)
+  | C.InductiveDefinition (_, params, _, _) ->
+      params
+
+let attributes_of_obj = function
+  | C.Constant (_, _, _, _, attributes)
+  | C.Variable (_, _, _, _, attributes)
+  | C.CurrentProof (_, _, _, _, _, attributes)
+  | C.InductiveDefinition (_, _, _, attributes) ->
+      attributes
+
+let is_generated obj = List.exists ((=) `Generated) (attributes_of_obj obj)
+
+let arity_of_composed_coercion obj =
+  let attrs = attributes_of_obj obj in
+  try
+    let tag=List.find (function `Class (`Coercion _) -> true|_->false) attrs in
+    match tag with
+    |  `Class (`Coercion n) -> n
+    | _-> assert false 
+  with Not_found -> 0
+;;
+
+let projections_of_record obj uri =
+  let attrs = attributes_of_obj obj in
+  try
+    let tag=List.find (function `Class (`Record _) -> true|_->false) attrs in
+    match tag with
+    |  `Class (`Record l) -> 
+         List.map (fun (name,_,_) ->
+           let buri = UriManager.buri_of_uri uri in
+           let puri = UriManager.uri_of_string (buri ^ "/" ^ name ^ ".con") in
+           puri) l
+    | _-> assert false 
+  with Not_found -> []
+;;
+      
+let rec mk_rels howmany from =
+  match howmany with 
+  | 0 -> []
+  | _ -> (C.Rel (howmany + from)) :: (mk_rels (howmany-1) from)
+
+let id_of_annterm =
+  function
+  | C.ARel (id,_,_,_)
+  | C.AVar (id,_,_)
+  | C.AMeta (id,_,_)
+  | C.ASort (id,_)
+  | C.AImplicit (id,_)
+  | C.ACast (id,_,_)
+  | C.AProd (id,_,_,_)
+  | C.ALambda (id,_,_,_)
+  | C.ALetIn (id,_,_,_,_)
+  | C.AAppl (id,_)
+  | C.AConst (id,_,_)
+  | C.AMutInd (id,_,_,_)
+  | C.AMutConstruct (id,_,_,_,_)
+  | C.AMutCase (id,_,_,_,_,_)
+  | C.AFix (id,_,_)
+  | C.ACoFix (id,_,_) -> id
+
+
+let rec rehash_term =
+  let module C = Cic in
+  let recons uri = UriManager.uri_of_string (UriManager.string_of_uri uri) in
+  function
+   | (C.Rel _) as t -> t
+   | C.Var (uri,exp_named_subst) ->
+      let uri' = recons uri in
+      let exp_named_subst' =
+       List.map
+        (function (uri,t) ->(recons uri,rehash_term t)) 
+         exp_named_subst
+      in
+       C.Var (uri',exp_named_subst')
+   | C.Meta (i,l) ->
+      let l' =
+       List.map
+        (function
+            None -> None
+          | Some t -> Some (rehash_term t)
+        ) l
+      in
+       C.Meta(i,l')
+   | C.Sort (C.Type u) -> 
+       CicUniv.assert_univ u;
+       C.Sort (C.Type (CicUniv.recons_univ u))
+   | C.Sort _ as t -> t
+   | C.Implicit _ as t -> t
+   | C.Cast (te,ty) -> C.Cast (rehash_term te, rehash_term ty)
+   | C.Prod (n,s,t) -> C.Prod (n, rehash_term s, rehash_term t)
+   | C.Lambda (n,s,t) -> C.Lambda (n, rehash_term s, rehash_term t)
+   | C.LetIn (n,s,ty,t) ->
+      C.LetIn (n, rehash_term s, rehash_term ty, rehash_term t)
+   | C.Appl l -> C.Appl (List.map rehash_term l)
+   | C.Const (uri,exp_named_subst) ->
+      let uri' = recons uri in
+      let exp_named_subst' = 
+       List.map
+        (function (uri,t) -> (recons uri,rehash_term t)) exp_named_subst
+      in
+       C.Const (uri',exp_named_subst')
+   | C.MutInd (uri,tyno,exp_named_subst) ->
+      let uri' = recons uri in
+      let exp_named_subst' = 
+       List.map
+        (function (uri,t) -> (recons uri,rehash_term t)) exp_named_subst
+      in
+       C.MutInd (uri',tyno,exp_named_subst')
+   | C.MutConstruct (uri,tyno,consno,exp_named_subst) ->
+      let uri' = recons uri in
+      let exp_named_subst' = 
+       List.map
+        (function (uri,t) -> (recons uri,rehash_term t)) exp_named_subst
+      in
+       C.MutConstruct (uri',tyno,consno,exp_named_subst')
+   | C.MutCase (uri,i,outty,t,pl) ->
+      C.MutCase (recons uri, i, rehash_term outty, rehash_term t,
+       List.map rehash_term pl)
+   | C.Fix (i, fl) ->
+      let liftedfl =
+       List.map
+        (fun (name, i, ty, bo) ->
+          (name, i, rehash_term ty, rehash_term bo))
+         fl
+      in
+       C.Fix (i, liftedfl)
+   | C.CoFix (i, fl) ->
+      let liftedfl =
+       List.map
+        (fun (name, ty, bo) -> (name, rehash_term ty, rehash_term bo))
+         fl
+      in
+       C.CoFix (i, liftedfl)
+
+let rehash_obj =
+ let module C = Cic in
+ let recons uri = UriManager.uri_of_string (UriManager.string_of_uri uri) in
+ function 
+   C.Constant (name,bo,ty,params,attrs) ->
+     let bo' =
+       match bo with
+         None -> None
+       | Some bo -> Some (rehash_term bo)
+     in
+     let ty' = rehash_term ty in
+     let params' = List.map recons params in
+     C.Constant (name, bo', ty', params',attrs)
+ | C.CurrentProof (name,conjs,bo,ty,params,attrs) ->
+     let conjs' =
+       List.map
+         (function (i,hyps,ty) ->
+           (i,
+           List.map (function
+               None -> None
+             | Some (name,C.Decl t) ->
+                 Some (name,C.Decl (rehash_term t))
+             | Some (name,C.Def (bo,ty)) ->
+                 Some (name,C.Def (rehash_term bo, rehash_term ty))) hyps,
+           rehash_term ty))
+         conjs
+     in
+     let bo' = rehash_term bo in
+     let ty' = rehash_term ty in
+     let params' = List.map recons params in
+     C.CurrentProof (name, conjs', bo', ty', params',attrs)
+ | C.Variable (name,bo,ty,params,attrs) ->
+     let bo' =
+       match bo with
+         None -> None
+       | Some bo -> Some (rehash_term bo)
+     in
+     let ty' = rehash_term ty in
+     let params' = List.map recons params in
+     C.Variable (name, bo', ty', params',attrs)
+ | C.InductiveDefinition (tl,params,paramsno,attrs) ->
+     let params' = List.map recons params in
+     let tl' =
+       List.map (function (name, inductive, ty, constructors) ->
+         name,
+         inductive,
+         rehash_term ty,
+         (List.map
+           (function (name, ty) -> name, rehash_term ty)
+           constructors))
+         tl
+     in
+     C.InductiveDefinition (tl', params', paramsno, attrs)
+
+let rec metas_of_term = function
+  | C.Meta (i, c) -> [i,c]
+  | C.Var (_, ens) 
+  | C.Const (_, ens) 
+  | C.MutInd (_, _, ens) 
+  | C.MutConstruct (_, _, _, ens) ->
+      List.flatten (List.map (fun (u, t) -> metas_of_term t) ens)
+  | C.Cast (s, t)
+  | C.Prod (_, s, t)
+  | C.Lambda (_, s, t) -> (metas_of_term s) @ (metas_of_term t)
+  | C.LetIn (_, s, ty, t) ->
+     (metas_of_term s) @ (metas_of_term ty) @ (metas_of_term t)
+  | C.Appl l -> List.flatten (List.map metas_of_term l)
+  | C.MutCase (uri, i, s, t, l) ->
+      (metas_of_term s) @ (metas_of_term t) @
+        (List.flatten (List.map metas_of_term l))
+  | C.Fix (i, il) ->
+      List.flatten
+        (List.map (fun (s, i, t1, t2) ->
+                     (metas_of_term t1) @ (metas_of_term t2)) il)
+  | C.CoFix (i, il) ->
+      List.flatten
+        (List.map (fun (s, t1, t2) ->
+                     (metas_of_term t1) @ (metas_of_term t2)) il)
+  | _ -> []
+;;      
+
+module MetaOT = struct
+  type t = int * C.term option list
+  let compare = Pervasives.compare
+end
+
+module S = Set.Make(MetaOT)
+
+let rec metas_of_term_set = function
+  | C.Meta (i, c) -> S.singleton (i,c)
+  | C.Var (_, ens) 
+  | C.Const (_, ens) 
+  | C.MutInd (_, _, ens) 
+  | C.MutConstruct (_, _, _, ens) ->
+      List.fold_left 
+        (fun s (_,t) -> S.union s (metas_of_term_set t)) 
+        S.empty ens
+  | C.Cast (s, t)
+  | C.Prod (_, s, t)
+  | C.Lambda (_, s, t) -> S.union (metas_of_term_set s) (metas_of_term_set t)
+  | C.LetIn (_, s, ty, t) ->
+     S.union (metas_of_term_set s)
+      (S.union (metas_of_term_set ty) (metas_of_term_set t))
+  | C.Appl l -> 
+      List.fold_left 
+        (fun s t -> S.union s (metas_of_term_set t)) 
+        S.empty l
+  | C.MutCase (uri, i, s, t, l) ->
+      S.union 
+        (S.union (metas_of_term_set s)  (metas_of_term_set t))
+        (List.fold_left 
+          (fun s t -> S.union s (metas_of_term_set t)) 
+          S.empty l)
+  | C.Fix (_, il) ->
+      (List.fold_left 
+        (fun s (_,_,t1,t2) -> 
+          S.union s (S.union (metas_of_term_set t1) (metas_of_term_set t2))))
+        S.empty il
+  | C.CoFix (i, il) ->
+      (List.fold_left 
+        (fun s (_,t1,t2) -> 
+          S.union s (S.union (metas_of_term_set t1) (metas_of_term_set t2))))
+        S.empty il
+  | _ -> S.empty
+;;      
+
+let metas_of_term_set t = 
+  let s = metas_of_term_set t in
+  S.elements s
+;;
+
+(* syntactic_equality up to the                 *)
+(* distinction between fake dependent products  *)
+(* and non-dependent products, alfa-conversion  *)
+let alpha_equivalence =
+  let rec aux t t' =
+   if t = t' then true
+   else
+    match t,t' with
+       C.Var (uri1,exp_named_subst1), C.Var (uri2,exp_named_subst2) ->
+        UriManager.eq uri1 uri2 &&
+         aux_exp_named_subst exp_named_subst1 exp_named_subst2
+     | C.Cast (te,ty), C.Cast (te',ty') ->
+        aux te te' && aux ty ty'
+     | C.Prod (_,s,t), C.Prod (_,s',t') ->
+        aux s s' && aux t t'
+     | C.Lambda (_,s,t), C.Lambda (_,s',t') ->
+        aux s s' && aux t t'
+     | C.LetIn (_,s,ty,t), C.LetIn(_,s',ty',t') ->
+        aux s s' && aux ty ty' && aux t t'
+     | C.Appl l, C.Appl l' when List.length l = List.length l' ->
+        (try
+          List.fold_left2
+           (fun b t1 t2 -> b && aux t1 t2) true l l'
+         with
+          Invalid_argument _ -> false)
+     | C.Const (uri,exp_named_subst1), C.Const (uri',exp_named_subst2) ->
+        UriManager.eq uri uri' &&
+         aux_exp_named_subst exp_named_subst1 exp_named_subst2
+     | C.MutInd (uri,i,exp_named_subst1), C.MutInd (uri',i',exp_named_subst2) ->
+        UriManager.eq uri uri' && i = i' &&
+         aux_exp_named_subst exp_named_subst1 exp_named_subst2
+     | C.MutConstruct (uri,i,j,exp_named_subst1),
+       C.MutConstruct (uri',i',j',exp_named_subst2) ->
+        UriManager.eq uri uri' && i = i' && j = j' &&
+         aux_exp_named_subst exp_named_subst1 exp_named_subst2
+     | C.MutCase (sp,i,outt,t,pl), C.MutCase (sp',i',outt',t',pl') ->
+        UriManager.eq sp sp' && i = i' &&
+         aux outt outt' && aux t t' &&
+          (try
+            List.fold_left2
+             (fun b t1 t2 -> b && aux t1 t2) true pl pl'
+           with
+            Invalid_argument _ -> false)
+     | C.Fix (i,fl), C.Fix (i',fl') ->
+        i = i' &&
+        (try
+          List.fold_left2
+           (fun b (_,i,ty,bo) (_,i',ty',bo') ->
+             b && i = i' && aux ty ty' && aux bo bo'
+           ) true fl fl'
+         with
+          Invalid_argument _ -> false)
+     | C.CoFix (i,fl), C.CoFix (i',fl') ->
+        i = i' &&
+        (try
+          List.fold_left2
+           (fun b (_,ty,bo) (_,ty',bo') ->
+             b && aux ty ty' && aux bo bo'
+           ) true fl fl'
+         with
+          Invalid_argument _ -> false)
+     | C.Meta (i, subst), C.Meta (i', subst') ->
+        i = i' &&
+        (try
+          List.fold_left2
+           (fun b xt xt' -> match xt,xt' with
+	     | Some t, Some t' -> b && aux t t'
+	     | _               -> b
+           ) true subst subst'
+         with
+          Invalid_argument _ -> false)
+     | C.Appl [t], t' | t, C.Appl [t'] -> assert false
+(* FG: are we _really_ sure of these?      
+     | C.Sort (C.Type u), C.Sort (C.Type u') -> u = u' 
+     | C.Implicit a, C.Implicit a' -> a = a'
+   we insert an unused variable below to genarate a warning at compile time
+*)     
+     | _,_ -> false (* we already know that t != t' *)
+  and aux_exp_named_subst exp_named_subst1 exp_named_subst2 =
+   try
+     List.fold_left2
+      (fun b (uri1,t1) (uri2,t2) ->
+        b && UriManager.eq uri1 uri2 && aux t1 t2
+      ) true exp_named_subst1 exp_named_subst2
+    with
+     Invalid_argument _ -> false
+  in
+   aux
+
+let is_sober t =
+   let rec sober_term g = function
+      | C.Rel _ 
+      | C.Sort _  
+      | C.Implicit _                    -> g      
+      | C.Const (_, xnss) 
+      | C.Var (_, xnss) 
+      | C.MutConstruct (_, _, _, xnss)
+      | C.MutInd (_, _, xnss)           -> sober_xnss g xnss
+      | C.Meta (_, xss)                 -> sober_xss g xss
+      | C.Lambda (_, v, t)
+      | C.Prod (_, v, t)
+      | C.Cast (t, v)                   -> sober_term (sober_term g t) v
+      | C.LetIn (_, v, ty, t)           -> sober_term
+                                            (sober_term (sober_term g t) ty) v
+      | C.Appl []                       
+      | C.Appl [_]                      -> fun b -> false
+      | C.Appl ts                       -> sober_terms g ts
+      | C.MutCase (_, _, t, v, ts)      -> 
+         sober_terms (sober_term (sober_term g t) v) ts
+      | C.Fix (_, ifs)                  -> sober_ifs g ifs
+      | C.CoFix (_, cifs)               -> sober_cifs g cifs
+   and sober_terms g = List.fold_left sober_term g
+   and sober_xnss g =
+      let map g (_, t) = sober_term g t in
+      List.fold_left map g
+   and sober_xss g =
+      let map g = function 
+         | None   -> g
+	 | Some t -> sober_term g t
+      in
+      List.fold_left map g
+   and sober_ifs g =
+      let map g (_, _, t, v) = sober_term (sober_term g t) v in
+      List.fold_left map g
+   and sober_cifs g =
+      let map g (_, t, v) = sober_term (sober_term g t) v in
+      List.fold_left map g
+   in 
+   sober_term (fun b -> b) t true