val is_blank : char -> boolval trim : string -> stringval split_lines : string -> string listval starts_with : prefix:string -> string -> boolval start_substr : prefix:string -> string -> bool * stringval cmp_float : ?epsilon:float -> float -> float -> boolval mapi : ('a -> int -> 'b) -> 'a list -> 'b listval fold_lefti : ('a -> 'b -> int -> 'a) -> 'a -> 'b list -> 'aval time_fun : ('a -> 'b) -> 'a -> float * 'bval date_iso8601 : ?tz:bool -> float -> stringval failwithf : ('a, unit, string, 'b) format4 -> 'aval opt : ('a -> unit) -> 'a option -> unitval fqdn : unit -> stringval shardf : int -> stringval make_counter : unit -> (unit -> ('a * int) list) * ('a -> unit)