in
subst_term
-
-
-
-(* Takes a well-typed term and fully reduces it. *)
-(*CSC: It does not perform reduction in a Case *)
-let reduce context =
- let rec reduceaux context l =
- function
- C.Rel n as t ->
- (match List.nth context (n-1) with
- Some (_,C.Decl _) -> if l = [] then t else C.Appl (t::l)
- | Some (_,C.Def (bo,_)) -> reduceaux context l (S.lift n bo)
- | None -> raise RelToHiddenHypothesis
- )
- | C.Var (uri,exp_named_subst) ->
- let exp_named_subst' =
- reduceaux_exp_named_subst context l exp_named_subst
- in
- (let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
- match o with
- C.Constant _ -> raise ReferenceToConstant
- | C.CurrentProof _ -> raise ReferenceToCurrentProof
- | C.InductiveDefinition _ -> raise ReferenceToInductiveDefinition
- | C.Variable (_,None,_,_,_) ->
- let t' = C.Var (uri,exp_named_subst') in
- if l = [] then t' else C.Appl (t'::l)
- | C.Variable (_,Some body,_,_,_) ->
- (reduceaux context l
- (CicSubstitution.subst_vars exp_named_subst' body))
- )
- | C.Meta _ as t -> if l = [] then t else C.Appl (t::l)
- | C.Sort _ as t -> t (* l should be empty *)
- | C.Implicit _ as t -> t
- | C.Cast (te,ty) ->
- C.Cast (reduceaux context l te, reduceaux context l ty)
- | C.Prod (name,s,t) ->
- assert (l = []) ;
- C.Prod (name,
- reduceaux context [] s,
- reduceaux ((Some (name,C.Decl s))::context) [] t)
- | C.Lambda (name,s,t) ->
- (match l with
- [] ->
- C.Lambda (name,
- reduceaux context [] s,
- reduceaux ((Some (name,C.Decl s))::context) [] t)
- | he::tl -> reduceaux context tl (S.subst he t)
- (* when name is Anonimous the substitution should be superfluous *)
- )
- | C.LetIn (n,s,t) ->
- reduceaux context l (S.subst (reduceaux context [] s) t)
- | C.Appl (he::tl) ->
- let tl' = List.map (reduceaux context []) tl in
- reduceaux context (tl'@l) he
- | C.Appl [] -> raise (Impossible 1)
- | C.Const (uri,exp_named_subst) ->
- let exp_named_subst' =
- reduceaux_exp_named_subst context l exp_named_subst
- in
- (let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph uri in
- match o with
- C.Constant (_,Some body,_,_,_) ->
- (reduceaux context l
- (CicSubstitution.subst_vars exp_named_subst' body))
- | C.Constant (_,None,_,_,_) ->
- let t' = C.Const (uri,exp_named_subst') in
- if l = [] then t' else C.Appl (t'::l)
- | C.Variable _ -> raise ReferenceToVariable
- | C.CurrentProof (_,_,body,_,_,_) ->
- (reduceaux context l
- (CicSubstitution.subst_vars exp_named_subst' body))
- | C.InductiveDefinition _ -> raise ReferenceToInductiveDefinition
- )
- | C.MutInd (uri,i,exp_named_subst) ->
- let exp_named_subst' =
- reduceaux_exp_named_subst context l exp_named_subst
- in
- let t' = C.MutInd (uri,i,exp_named_subst') in
- if l = [] then t' else C.Appl (t'::l)
- | C.MutConstruct (uri,i,j,exp_named_subst) ->
- let exp_named_subst' =
- reduceaux_exp_named_subst context l exp_named_subst
- in
- let t' = C.MutConstruct (uri,i,j,exp_named_subst') in
- if l = [] then t' else C.Appl (t'::l)
- | C.MutCase (mutind,i,outtype,term,pl) ->
- let decofix =
- function
- C.CoFix (i,fl) ->
- let (_,_,body) = List.nth fl i in
- let body' =
- let counter = ref (List.length fl) in
- List.fold_right
- (fun _ -> decr counter ; S.subst (C.CoFix (!counter,fl)))
- fl
- body
- in
- reduceaux context [] body'
- | C.Appl (C.CoFix (i,fl) :: tl) ->
- let (_,_,body) = List.nth fl i in
- let body' =
- let counter = ref (List.length fl) in
- List.fold_right
- (fun _ -> decr counter ; S.subst (C.CoFix (!counter,fl)))
- fl
- body
- in
- let tl' = List.map (reduceaux context []) tl in
- reduceaux context tl' body'
- | t -> t
- in
- (match decofix (reduceaux context [] term) with
- C.MutConstruct (_,_,j,_) -> reduceaux context l (List.nth pl (j-1))
- | C.Appl (C.MutConstruct (_,_,j,_) :: tl) ->
- let (arity, r) =
- let o,_ = CicEnvironment.get_obj CicUniv.empty_ugraph mutind in
- match o with
- C.InductiveDefinition (tl,_,r,_) ->
- let (_,_,arity,_) = List.nth tl i in
- (arity,r)
- | _ -> raise WrongUriToInductiveDefinition
- in
- let ts =
- let rec eat_first =
- function
- (0,l) -> l
- | (n,he::tl) when n > 0 -> eat_first (n - 1, tl)
- | _ -> raise (Impossible 5)
- in
- eat_first (r,tl)
- in
- reduceaux context (ts@l) (List.nth pl (j-1))
- | C.Cast _ | C.Implicit _ ->
- raise (Impossible 2) (* we don't trust our whd ;-) *)
- | _ ->
- let outtype' = reduceaux context [] outtype in
- let term' = reduceaux context [] term in
- let pl' = List.map (reduceaux context []) pl in
- let res =
- C.MutCase (mutind,i,outtype',term',pl')
- in
- if l = [] then res else C.Appl (res::l)
- )
- | C.Fix (i,fl) ->
- let tys,_ =
- List.fold_left
- (fun (types,len) (n,_,ty,_) ->
- (Some (C.Name n,(C.Decl (CicSubstitution.lift len ty)))::types,
- len+1)
- ) ([],0) fl
- in
- let t' () =
- let fl' =
- List.map
- (function (n,recindex,ty,bo) ->
- (n,recindex,reduceaux context [] ty, reduceaux (tys@context) [] bo)
- ) fl
- in
- C.Fix (i, fl')
- in
- let (_,recindex,_,body) = List.nth fl i in
- let recparam =
- try
- Some (List.nth l recindex)
- with
- _ -> None
- in
- (match recparam with
- Some recparam ->
- (match reduceaux context [] recparam with
- C.MutConstruct _
- | C.Appl ((C.MutConstruct _)::_) ->
- let body' =
- let counter = ref (List.length fl) in
- List.fold_right
- (fun _ -> decr counter ; S.subst (C.Fix (!counter,fl)))
- fl
- body
- in
- (* Possible optimization: substituting whd recparam in l*)
- reduceaux context l body'
- | _ -> if l = [] then t' () else C.Appl ((t' ())::l)
- )
- | None -> if l = [] then t' () else C.Appl ((t' ())::l)
- )
- | C.CoFix (i,fl) ->
- let tys,_ =
- List.fold_left
- (fun (types,len) (n,ty,_) ->
- (Some (C.Name n,(C.Decl (CicSubstitution.lift len ty)))::types,
- len+1)
- ) ([],0) fl
- in
- let t' =
- let fl' =
- List.map
- (function (n,ty,bo) ->
- (n,reduceaux context [] ty, reduceaux (tys@context) [] bo)
- ) fl
- in
- C.CoFix (i, fl')
- in
- if l = [] then t' else C.Appl (t'::l)
- and reduceaux_exp_named_subst context l =
- List.map (function uri,t -> uri,reduceaux context [] t)
- in
- reduceaux context []
-;;
-
-
let unfold ?what context where =
let contextlen = List.length context in
let first_is_the_expandable_head_of_second context' t1 t2 =
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