Miscellaneous¶

Argparse version¶

argparse module is a table with __call metamethod. argparse.version is a string in MAJOR.MINOR.PATCH format specifying argparse version.

Overwriting default help option¶

If the property add_help of a parser is set to false, no help option will be added to it. Otherwise, the value of the field will be used to configure it.

local parser = argparse()
   :add_help "/?"

$ lua script.lua /?

Usage: script.lua [/?]

Options:
   /?                    Show this help message and exit.

Help command¶

A help command can be added to the parser using the :add_help_command([value]) method. It accepts an optional string or table value which is used to configure the command.

local parser = argparse()
   :add_help_command()
parser:command "install"
   :description "Install a rock."

$ lua script.lua help

Usage: script.lua [-h] <command> ...

Options:
   -h, --help            Show this help message and exit.

Commands:
   help                  Show help for commands.
   install               Install a rock.

$ lua script.lua help install

Usage: script.lua install [-h]

Install a rock.

Options:
   -h, --help            Show this help message and exit.

Disabling option handling¶

When handle_options property of a parser or a command is set to false, all options will be passed verbatim to the argument list, as if the input included double-hyphens.

parser:handle_options(false)
parser:argument "input"
   :args "*"
parser:option "-f" "--foo"
   :args "*"

$ lua script.lua bar -f --foo bar

{
   input = {"bar", "-f", "--foo", "bar"}
}

Prohibiting overuse of options¶

By default, if an option is invoked too many times, latest invocations overwrite the data passed earlier.

parser:option "-o --output"

$ lua script.lua -oFOO -oBAR

{
   output = "BAR"
}

Set overwrite property to false to prohibit this behavior.

parser:option "-o --output"
   :overwrite(false)

$ lua script.lua -oFOO -oBAR

Usage: script.lua [-h] [-o <output>]

Error: option '-o' must be used at most 1 time

Parsing algorithm¶

argparse interprets command line arguments in the following way:

Argument	Interpretation
`foo`	An argument of an option or a positional argument.
`--foo`	An option.
`--foo=bar`	An option and its argument. The option must be able to take arguments.
`-f`	An option.
`-abcdef`	Letters are interpreted as options. If one of them can take an argument, the rest of the string is passed to it.
`--`	The rest of the command line arguments will be interpreted as positional arguments.

Property lists¶

Parser properties¶

Properties that can be set as arguments when calling or constructing a parser, in this order:

Property	Type
`name`	String
`description`	String
`epilog`	String

Other properties:

Property	Type
`usage`	String
`help`	String
`require_command`	Boolean
`handle_options`	Boolean
`add_help`	Boolean or string or table
`command_target`	String
`usage_max_width`	Number
`usage_margin`	Number
`help_max_width`	Number
`help_usage_margin`	Number
`help_description_margin`	Number
`help_vertical_space`	Number

Command properties¶

Properties that can be set as arguments when calling or constructing a command, in this order:

Property	Type
`name`	String
`description`	String
`epilog`	String

Other properties:

Property	Type
`hidden_name`	String
`summary`	String
`target`	String
`usage`	String
`help`	String
`require_command`	Boolean
`handle_options`	Boolean
`action`	Function
`add_help`	Boolean or string or table
`command_target`	String
`hidden`	Boolean
`usage_max_width`	Number
`usage_margin`	Number
`help_max_width`	Number
`help_usage_margin`	Number
`help_description_margin`	Number
`help_vertical_space`	Number

Argument properties¶

Properties that can be set as arguments when calling or constructing an argument, in this order:

Property	Type
`name`	String
`description`	String
`default`	Any
`convert`	Function or table
`args`	Number or string

Other properties:

Property	Type
`target`	String
`defmode`	String
`show_default`	Boolean
`argname`	String or table
`choices`	Table
`action`	Function or string
`init`	Any
`hidden`	Boolean

Option and flag properties¶

Properties that can be set as arguments when calling or constructing an option or a flag, in this order:

Property	Type
`name`	String
`description`	String
`default`	Any
`convert`	Function or table
`args`	Number or string
`count`	Number or string

Other properties:

Property	Type
`hidden_name`	String
`target`	String
`defmode`	String
`show_default`	Boolean
`overwrite`	Booleans
`argname`	String or table
`choices`	Table
`action`	Function or string
`init`	Any
`hidden`	Boolean