Struct Arg

pub struct Arg { /* private fields */ }

Represents a single argument which can be passed to a Parser.

Example

let arg = Arg::new().param("num");
let parser = Parser::new();
let mut args = std::env::args();
args.next();
 
parser.add_arg(arg);
let output = parser.parse(&mut args).unwrap();

Implementations

impl Arg

pub fn new() -> Arg

Create a new arg object, note you must call further methods on this for it to be useful.

Example

let arg = Arg::new();

pub fn param(self, name: &str) -> Arg

A parameter argument, or one that does not expect any argument to come before it. Note that the order that these are added to the parser matters.

Example

let arg = Arg::new().param("p1");

arg is a required argument and the Parser::parse() will return an error if it is not present.

pub fn input(self, name: &str) -> Arg

An optional argument that expects a value to follow directly after it.

Example

let arg = Arg::new().input("inp");

Upon parsing, if --inp is one of the arguments called, arg will be in the output with whatever string comes next in the arguments.

pub fn flag(self, name: &str) -> Arg

A flag argument, or one that toggles a setting without expecting another token afterwards.

Example

let arg = Arg::new().flag("optional");

Upon parsing, if --optional is one of the arguments called, arg will be in the output with the value true.

pub fn short(self, ch: char) -> Arg

Sets a short option for the argument, allowing it to be called with a char rather than a string.

Example

let arg = Arg::new().flag("help").short('h');

The arg variable can be called by --help or by -h.

Trait Implementations

impl Clone for Arg

fn clone(&self) -> Arg

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Arg

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.