and aux_substs env substs =
List.map (fun (name, term) -> (name, aux env term)) substs
and aux_meta_substs env meta_substs = List.map (aux_opt env) meta_substs
and aux_variable env = function
| Ast.NumVar name -> Ast.Num (Env.lookup_num env name, 0)
and aux_substs env substs =
List.map (fun (name, term) -> (name, aux env term)) substs
and aux_meta_substs env meta_substs = List.map (aux_opt env) meta_substs
and aux_variable env = function
| Ast.NumVar name -> Ast.Num (Env.lookup_num env name, 0)