# Module BatOptParse.OptParser

    module OptParser: sig .. end

This module contains the option parser itself.

It provides functions to create, populate and use option parsers to parse command line arguments.

###### Exceptions

    exception Option_conflict of string

`Option_conflict name` is raised by `OptParse.OptParser.add` when two different options are added with identical names. Usually this doesn't need to be caught since this error is usually easily fixed permanently by removing/renaming the conflicting option names.

###### Types

    type t

The type of an option parser.

    type group

The type of an option group.

###### Option parser creation

    val make : ?usage:string ->
           ?description:string ->
           ?version:string ->
           ?suppress_usage:bool ->
           ?suppress_help:bool ->
           ?only_leading_opts:bool ->
           ?prog:string ->
           ?formatter:BatOptParse.Formatter.t -> unit -> t

Creates a new option parser with the given options.
Returns the new option parser.
`usage` : Usage message. The default is a reasonable usage message for most programs. Any occurrence of the substring `"%prog"` in `usage` is replaced with the name of the program (see `prog`).
`version` : Version string. If set, a '--version' option is automatically added. When encountered on the command line it causes `version` to be printed to the standard output and the program to exit.
`suppress_usage` : Suppress the usage message if set.
`suppress_help` : Suppress the 'help' option which is otherwise added by default.
`only_leading_opts` : Only consider leading options (options appearing before the first non-option argument). All arguments from the first non-option argument on are returned as the arguments.
`prog` : Program name. The default is the base name of the executable.

    val add : t ->
           ?group:group ->
           ?help:string ->
           ?hide:bool ->
           ?short_name:char ->
           ?short_names:char list ->
           ?long_name:string -> ?long_names:string list -> 'a BatOptParse.Opt.t -> unit

Add an option to the option parser.
Raises `Option_conflict` if the short name(s) or long name(s) have alread been used for some other option.
`help` : Short help message describing the option (for the usage message).
`hide` : If true, hide the option from the usage message. This can be used to implement "secret" options which are not shown, but work just the same as regular options in all other respects.
`short_name` : is the name for the short form of the option (e.g. `'x'` means that the option is invoked with `-x` on the command line).
`short_names` : is a list of names for the short form of the option (see `short_name`).
`long_name` : is the name for the long form of the option (e.g. `"xyzzy"` means that the option is invoked with `--xyzzy` on the command line).
`long_names` : is a list of names for the long form of the option (see `long_name`).

    val add_group : t ->
           ?parent:group ->
           ?description:string -> string -> group

Add a group to the option parser.
Returns the new group.
`parent` : is the parent group (if any).
`description` : is a description of the group.

###### Output and error handling

    val error : t ->
           ?chn:Pervasives.out_channel -> ?status:int -> string -> unit

Display an error message and exit the program. The error message is printed to the channel `chn` (default is `Pervasives.stderr`) and the program exits with exit status `status` (default is 1).

    val usage : t -> ?chn:Pervasives.out_channel -> unit -> unit

Display the usage message to the channel `chn` (default is `Pervasives.stdout`) and return.

###### Option parsing

    val parse : t ->
           ?first:int -> ?last:int -> string array -> string list

Parse arguments as if the arguments `args.(first)`, `args.(first+1)`, ..., `args.(last)` had been given on the command line. By default `first` is 0 and `last` is the index of the last element of the array.

    val parse_argv : t -> string list

Parse all the arguments in `Sys.argv`.