Trait Parser

pub trait Parser:
    Sized
    + FromArgMatches
    + CommandFactory {
    // Provided methods
    fn parse() -> Self { ... }
    fn try_parse() -> Result<Self, Error> { ... }
    fn parse_from<I, T>(itr: I) -> Self
       where I: IntoIterator<Item = T>,
             T: Into<OsString> + Clone { ... }
    fn try_parse_from<I, T>(itr: I) -> Result<Self, Error>
       where I: IntoIterator<Item = T>,
             T: Into<OsString> + Clone { ... }
    fn update_from<I, T>(&mut self, itr: I)
       where I: IntoIterator<Item = T>,
             T: Into<OsString> + Clone { ... }
    fn try_update_from<I, T>(&mut self, itr: I) -> Result<(), Error>
       where I: IntoIterator<Item = T>,
             T: Into<OsString> + Clone { ... }
}

Parse command-line arguments into Self.

The primary one-stop-shop trait used to create an instance of a clap Command, conduct the parsing, and turn the resulting ArgMatches back into concrete instance of the user struct.

This trait is primarily a convenience on top of FromArgMatches + CommandFactory which uses those two underlying traits to build the two fundamental functions parse which uses the std::env::args_os iterator, and parse_from which allows the consumer to supply the iterator (along with fallible options for each).

See also Subcommand and Args.

NOTE: Deriving requires the derive feature flag

Provided Methods

fn parse() -> Self

Parse from std::env::args_os(), exit on error.

fn try_parse() -> Result<Self, Error>

Parse from std::env::args_os(), return Err on error.

fn parse_from<I, T>(itr: I) -> Self

where I: IntoIterator<Item = T>, T: Into<OsString> + Clone,

Parse from iterator, exit on error.

fn try_parse_from<I, T>(itr: I) -> Result<Self, Error>

where I: IntoIterator<Item = T>, T: Into<OsString> + Clone,

Parse from iterator, return Err on error.

fn update_from<I, T>(&mut self, itr: I)

where I: IntoIterator<Item = T>, T: Into<OsString> + Clone,

Update from iterator, exit on error.

Unlike Parser::parse, this works with an existing instance of self. The assumption is that all required fields are already provided and any Args or Subcommands provided by the user will modify only what is specified.

fn try_update_from<I, T>(&mut self, itr: I) -> Result<(), Error>

where I: IntoIterator<Item = T>, T: Into<OsString> + Clone,

Update from iterator, return Err on error.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T> Parser for Box<T>

where T: Parser,

fn parse() -> Box<T>

fn try_parse() -> Result<Box<T>, Error>

fn parse_from<I, It>(itr: I) -> Box<T>

where I: IntoIterator<Item = It>, It: Into<OsString> + Clone,

fn try_parse_from<I, It>(itr: I) -> Result<Box<T>, Error>

where I: IntoIterator<Item = It>, It: Into<OsString> + Clone,

Implementors