Batteries user guide : Batteries.Legacy.Arg

`sig
type spec =
Arg.spec =
Unit of (unit -> unit)
| Bool of (bool -> unit)
| Set of bool ref
| Clear of bool ref
| String of (string -> unit)
| Set_string of string ref
| Int of (int -> unit)
| Set_int of int ref
| Float of (float -> unit)
| Set_float of float ref
| Tuple of spec list
| Symbol of string list * (string -> unit)
| Rest of (string -> unit)
type key = string
type doc = string
type usage_msg = string
type anon_fun = string -> unit
val parse : (key * spec * doc) list -> anon_fun -> usage_msg -> unit
val parse_dynamic :
(string * spec * string) list ref -> anon_fun -> string -> unit
val parse_argv :
?current:int ref ->
string array -> (key * spec * doc) list -> anon_fun -> usage_msg -> unit
val parse_argv_dynamic :
?current:int ref ->
string array ->
(string * spec * string) list ref -> anon_fun -> string -> unit
exception Help of string
exception Bad of string
val usage : (key * spec * doc) list -> usage_msg -> unit
val usage_string : (key * spec * doc) list -> usage_msg -> string
val align : (key * spec * doc) list -> (key * spec * doc) list
val current : int ref
end`