Sourceval const : 'a -> 'b -> 'a Sourceval o : ('a -> 'b) -> ('c -> 'a) -> 'c -> 'b Sourceval filter_map : f:('a -> 'b option) -> 'a list -> 'b list Sourceval map_find : f:('a -> 'b option) -> 'a list -> 'b option Sourceval option : 'a -> ('b -> 'a) -> 'b option -> 'a Sourceval init_and_last : 'a list -> ('a list * 'a) option Sourceval first_match : 'a list -> 'a list -> 'a option