module Arg:sig..end
This module provides a general mechanism for extracting options and arguments from the command line to the program.
Syntax of command lines:
A keyword is a character string starting with a -.
An option is a keyword alone or followed by an argument.
The types of keywords are: Unit, Bool, Set, Clear,
String, Set_string, Int, Set_int, Float, Set_float,
Tuple, Symbol, and Rest.
Unit, Set and Clear keywords take no argument. A Rest
keyword takes the remaining of the command line as arguments.
Every other keyword takes the following word on the command line
as argument. For compatibility with GNU getopt_long, keyword=arg
is also allowed.
Arguments not preceded by a keyword are called anonymous arguments.
Examples (cmd is assumed to be the command name):
cmd -flag (a unit option)cmd -int 1 (an int option with argument 1)cmd -string foobar (a string option with argument "foobar")cmd -float 12.34 (a float option with argument 12.34)cmd a b c (three anonymous arguments: "a", "b", and "c")cmd a b -- c d (two anonymous arguments and a rest option with
two arguments)type spec =
| |
Unit of |
(* |
Call the function with unit argument
| *) |
| |
Bool of |
(* |
Call the function with a bool argument
| *) |
| |
Set of |
(* |
Set the reference to true
| *) |
| |
Clear of |
(* |
Set the reference to false
| *) |
| |
String of |
(* |
Call the function with a string argument
| *) |
| |
Set_string of |
(* |
Set the reference to the string argument
| *) |
| |
Int of |
(* |
Call the function with an int argument
| *) |
| |
Set_int of |
(* |
Set the reference to the int argument
| *) |
| |
Float of |
(* |
Call the function with a float argument
| *) |
| |
Set_float of |
(* |
Set the reference to the float argument
| *) |
| |
Tuple of |
(* |
Take several arguments according to the
spec list
| *) |
| |
Symbol of |
(* |
Take one of the symbols as argument and
call the function with the symbol
| *) |
| |
Rest of |
(* |
Stop interpreting keywords and call the
function with each remaining argument
| *) |
| |
Expand of |
(* |
If the remaining arguments to process
are of the form
["-foo"; "arg"] @ rest where "foo" is
registered as Expand f, then the
arguments f "arg" @ rest are
processed. Only allowed in
parse_and_expand_argv_dynamic. | *) |
typekey =string
typedoc =string
typeusage_msg =string
typeanon_fun =string -> unit
val parse : (key * spec * doc) list -> anon_fun -> usage_msg -> unitArg.parse speclist anon_fun usage_msg parses the command line.
speclist is a list of triples (key, spec, doc).
key is the option keyword, it must start with a '-' character.
spec gives the option type and the function to call when this option
is found on the command line.
doc is a one-line description of this option.
anon_fun is called on anonymous arguments.
The functions in spec and anon_fun are called in the same order
as their arguments appear on the command line.
If an error occurs, Arg.parse exits the program, after printing
to standard error an error message as follows:
usage_msgdoc string.
Beware: options that have an empty doc string will not be included in the
list.-, include for example ("-", String anon_fun, doc) in speclist.
By default, parse recognizes two unit options, -help and --help,
which will print to standard output usage_msg and the list of
options, and exit the program. You can override this behaviour
by specifying your own -help and --help options in speclist.
val parse_dynamic : (key * spec * doc) list ref ->
anon_fun -> usage_msg -> unitArg.parse, except that the speclist argument is a reference
and may be updated during the parsing. A typical use for this feature
is to parse command lines of the form:options
where the list of options depends on the value of the subcommand argument.val parse_argv : ?current:int ref ->
string array ->
(key * spec * doc) list -> anon_fun -> usage_msg -> unitArg.parse_argv ~current args speclist anon_fun usage_msg parses
the array args as if it were the command line. It uses and updates
the value of ~current (if given), or Arg.current. You must set
it before calling parse_argv. The initial value of current
is the index of the program name (argument 0) in the array.
If an error occurs, Arg.parse_argv raises Arg.Bad with
the error message as argument. If option -help or --help is
given, Arg.parse_argv raises Arg.Help with the help message
as argument.val parse_argv_dynamic : ?current:int ref ->
string array ->
(key * spec * doc) list ref ->
anon_fun -> string -> unitArg.parse_argv, except that the speclist argument is a
reference and may be updated during the parsing.
See Arg.parse_dynamic.val parse_and_expand_argv_dynamic : int ref ->
string array ref ->
(key * spec * doc) list ref ->
anon_fun -> string -> unitArg.parse_argv_dynamic, except that the argv argument is a
reference and may be updated during the parsing of Expand arguments.
See Arg.parse_argv_dynamic.val parse_expand : (key * spec * doc) list -> anon_fun -> usage_msg -> unitArg.parse, except that the Expand arguments are allowed and
the Arg.current reference is not updated.exception Help of string
Arg.parse_argv when the user asks for help.exception Bad of string
spec or anon_fun can raise Arg.Bad with an error
message to reject invalid arguments.
Arg.Bad is also raised by Arg.parse_argv in case of an error.val usage : (key * spec * doc) list -> usage_msg -> unitArg.usage speclist usage_msg prints to standard error
an error message that includes the list of valid options. This is
the same message that Arg.parse prints in case of error.
speclist and usage_msg are the same as for Arg.parse.val usage_string : (key * spec * doc) list -> usage_msg -> stringArg.usage,
if provided with the same parameters.val align : ?limit:int ->
(key * spec * doc) list -> (key * spec * doc) listSymbol arguments are aligned on the next line.limit : options with keyword and message longer than
limit will not be used to compute the alignement.val current : int refSys.argv) of the argument being processed. You can
change this value, e.g. to force Arg.parse to skip some arguments.
Arg.parse uses the initial value of Arg.current as the index of
argument 0 (the program name) and starts parsing arguments
at the next element.val read_arg : string -> string arrayArg.read_arg file reads newline-terminated command line arguments from
file file.val read_arg0 : string -> string arrayArg.read_arg but assumes null character terminated command line
arguments.val write_arg : string -> string array -> unitArg.write_arg file args writes the arguments args newline-terminated
into the file file. If the any of the arguments in args contains a
newline, use Arg.write_arg0 instead.val write_arg0 : string -> string array -> unitArg.write_arg but uses the null character for terminator
instead of newline.