-(* delifts a term t of n levels strating from k, that is changes (Rel m)
- * to (Rel (m - n)) when m > (k + n). if k <= m < k + n delift fails
- *)
-let delift_from k n =
- let rec liftaux k =
- let module C = Cic in
- function
- C.Rel m ->
- if m < k then
- C.Rel m
- else if m < k + n then
- (failwith "delifting this term whould capture free variables")
- else
- C.Rel (m - n)
- | C.Var (uri,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,liftaux k 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 (liftaux k t)
- ) l
- in
- C.Meta(i,l')
- | C.Sort _ as t -> t
- | C.Implicit _ as t -> t
- | C.Cast (te,ty) -> C.Cast (liftaux k te, liftaux k ty)
- | C.Prod (n,s,t) -> C.Prod (n, liftaux k s, liftaux (k+1) t)
- | C.Lambda (n,s,t) -> C.Lambda (n, liftaux k s, liftaux (k+1) t)
- | C.LetIn (n,s,t) -> C.LetIn (n, liftaux k s, liftaux (k+1) t)
- | C.Appl l -> C.Appl (List.map (liftaux k) l)
- | C.Const (uri,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,liftaux k t)) exp_named_subst
- in
- C.Const (uri,exp_named_subst')
- | C.MutInd (uri,tyno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,liftaux k t)) exp_named_subst
- in
- C.MutInd (uri,tyno,exp_named_subst')
- | C.MutConstruct (uri,tyno,consno,exp_named_subst) ->
- let exp_named_subst' =
- List.map (function (uri,t) -> (uri,liftaux k t)) exp_named_subst
- in
- C.MutConstruct (uri,tyno,consno,exp_named_subst')
- | C.MutCase (sp,i,outty,t,pl) ->
- C.MutCase (sp, i, liftaux k outty, liftaux k t,
- List.map (liftaux k) pl)
- | C.Fix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, i, ty, bo) -> (name, i, liftaux k ty, liftaux (k+len) bo))
- fl
- in
- C.Fix (i, liftedfl)
- | C.CoFix (i, fl) ->
- let len = List.length fl in
- let liftedfl =
- List.map
- (fun (name, ty, bo) -> (name, liftaux k ty, liftaux (k+len) bo))
- fl
- in
- C.CoFix (i, liftedfl)
- in
- liftaux k
-
-let delift n t =
- delift_from 1 n t
-