Adding and configuring arguments¶

Positional arguments can be added using :argument(name, description, default, convert, args) method. It returns an Argument instance, which can be configured in the same way as Parsers. The name property is required.

This and the following examples show contents of the result table returned by parser:parse() when the script is executed with given command-line arguments.

parser:argument "input"

$ lua script.lua foo

{
   input = "foo"
}

The data passed to the argument is stored in the result table at index input because it is the argument’s name. The index can be changed using target property.

Setting number of consumed arguments¶

args property sets how many command line arguments the argument consumes. Its value is interpreted as follows:

Value	Interpretation
Number `N`	Exactly `N` arguments
String `A-B`, where `A` and `B` are numbers	From `A` to `B` arguments
String `N+`, where `N` is a number	`N` or more arguments
String `?`	An optional argument
String `*`	Any number of arguments
String `+`	At least one argument

If more than one argument can be consumed, a table is used to store the data.

parser:argument("pair", "A pair of arguments.")
   :args(2)
parser:argument("optional", "An optional argument.")
   :args "?"

$ lua script.lua foo bar

{
   pair = {"foo", "bar"}
}

$ lua script.lua foo bar baz

{
   pair = {"foo", "bar"},
   optional = "baz"
}