val if_record : t -> f:(record_fields -> 'a) -> otherwise:(unit -> 'a) -> 'a
val if_array : t -> f:(t -> 'a) -> otherwise:(unit -> 'a) -> 'a
val if_record : t -> f:(record_fields -> 'a) -> otherwise:(unit -> 'a) -> 'a
val if_array : t -> f:(t -> 'a) -> otherwise:(unit -> 'a) -> 'a