Struct Arguments 

pub struct Arguments { /* private fields */ }

A parsed command line.

Implementations

impl Arguments

pub fn parse<I, S>(argv: I) -> Self

where I: IntoIterator<Item = S>, S: Into<String>,

Parse an argument list, without the program name.

The first positional word is the command; the rest belong to it.

pub fn command(&self) -> &str

The command name, or "" if none was given.

pub fn is_empty(&self) -> bool

Whether no command was given.

pub fn positional(&self) -> &[String]

The positional arguments after the command.

pub fn argument(&self, index: usize) -> Option<&str>

The positional argument at index, after the command.

pub fn option(&self, name: &str) -> Option<&str>

An option’s value.

Options are --name=value. A bare --name is a flag, so --port 8000 gives a flag called port and a stray positional 8000 — and the value goes nowhere.

That form cannot be supported without knowing which options take a value (--verbose migrate is a flag and a command, not an option), so instead it is reported: asking for an option that was given as a bare flag warns and says what to write. Serving on the wrong port because a = was missing is a bad afternoon.

pub fn option_or<'a>(&'a self, name: &str, default: &'a str) -> &'a str

An option’s value, or default.

pub fn parsed_or<T: FromStr>(&self, name: &str, default: T) -> T

An option parsed into T, or default if absent or unparsable.

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

Whether a flag was given.

pub fn is_valueless(&self, name: &str) -> bool

Whether name was given as a bare flag when a value was wanted.

What option warns about, exposed so a command can refuse rather than carry on with a default.

pub fn wants_help(&self) -> bool

Whether help was asked for, in any of its usual spellings.

pub fn options(&self) -> &HashMap<String, String>

Every option, for diagnostics.

pub fn flags(&self) -> &HashSet<String>

Every flag, for diagnostics.

Trait Implementations

impl Clone for Arguments

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Arguments

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

Formats the value using the given formatter.

impl Default for Arguments

fn default() -> Self

Returns the “default value” for a type.

impl Eq for Arguments

impl PartialEq for Arguments

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Arguments