Trait CommandLineArgument

pub trait CommandLineArgument {
    // Required methods
    fn parse_value(&mut self, arg: &str) -> Result<(), ArgError>;
    fn write_name(&self, name: Option<&str>) -> Option<String>;

    // Provided methods
    fn set_default(&mut self) -> Result<(), ArgError> { ... }
    fn set_unseen(&mut self) { ... }
    fn is_multi(&self) -> bool { ... }
    fn default_value(&self) -> Option<String> { ... }
}

Trait for variables that can be used as option arguments.

Required Methods

fn parse_value(&mut self, arg: &str) -> Result<(), ArgError>

Add the value from the command line string.

fn write_name(&self, name: Option<&str>) -> Option<String>

Return a description of a argument of this type.

name is a use-defined description (if any) of the underlying type. The function may add additional formatting.

Provided Methods

fn set_default(&mut self) -> Result<(), ArgError>

Called if the option has been specified without argument.

The method should return the error ArgError::MissingArgument if the argument is required.

fn set_unseen(&mut self)

Called if the argument has never been seen.

This method can be used to store a specific “never seen” value in the variable.

fn is_multi(&self) -> bool

Return true if the argument can parsed multiple times.

fn default_value(&self) -> Option<String>

Return the initial value as a string.

Implementations on Foreign Types

impl<'a> CommandLineArgument for &'a mut bool

A flag.

A flag must not take an argument but always uses its default value.

fn parse_value(&mut self, arg: &str) -> Result<(), ArgError>

fn set_default(&mut self) -> Result<(), ArgError>

fn write_name(&self, _name: Option<&str>) -> Option<String>

impl<'a, T> CommandLineArgument for &'a mut Option<T>

where T: FromStr + DefaultName + Display, <T as FromStr>::Err: StdError + 'static,

An optional argument option.

fn parse_value(&mut self, arg: &str) -> Result<(), ArgError>

fn set_default(&mut self) -> Result<(), ArgError>

fn set_unseen(&mut self)

fn default_value(&self) -> Option<String>

fn write_name(&self, name: Option<&str>) -> Option<String>

Implementors

impl<'a, T> CommandLineArgument for Multi<&'a mut Vec<T>>

where T: FromStr + DefaultName + Debug, <T as FromStr>::Err: StdError + 'static,

impl<'a, T> CommandLineArgument for Single<&'a mut T>

where T: FromStr + DefaultName + Display, <T as FromStr>::Err: StdError + 'static,