Trait gumdrop::Options

pub trait Options: Sized {
    fn parse<S: AsRef<str>>(parser: &mut Parser<S>) -> Result<Self, Error>;
    fn parse_command<S: AsRef<str>>(
        name: &str, 
        parser: &mut Parser<S>
    ) -> Result<Self, Error>;
    fn usage() -> &'static str;
    fn command_usage(command: &str) -> Option<&'static str>;
    fn command_list() -> Option<&'static str>;

    fn command_name(&self) -> Option<&'static str> { ... }
    fn help_requested(&self) -> bool { ... }
    fn parse_args<S: AsRef<str>>(
        args: &[S], 
        style: ParsingStyle
    ) -> Result<Self, Error> { ... }
    fn parse_args_or_exit(style: ParsingStyle) -> Self { ... }
    fn parse_args_default_or_exit() -> Self { ... }
    fn parse_args_default<S: AsRef<str>>(args: &[S]) -> Result<Self, Error> { ... }
}

Implements a set of options parsed from command line arguments.

An implementation of this trait can be generated with #[derive(Options)].

Required Methods

fn parse<S: AsRef<str>>(parser: &mut Parser<S>) -> Result<Self, Error>

Parses arguments until the given parser is exhausted or until an error is encountered.

fn parse_command<S: AsRef<str>>(
    name: &str,
    parser: &mut Parser<S>
) -> Result<Self, Error>

Parses options for the named command.

fn usage() -> &'static str

Returns a string showing usage and help for each supported option.

Option descriptions are separated by newlines. The returned string should not end with a newline.

fn command_usage(command: &str) -> Option<&'static str>

Returns a usage string for the named command.

If the named command does not exist, None is returned.

Command descriptions are separated by newlines. The returned string should not end with a newline.

fn command_list() -> Option<&'static str>

Returns a string listing available commands and help text.

Commands are separated by newlines. The string should not end with a newline.

For enum types with derive(Options), this is the same as usage.

For struct types containing a field marked #[options(command)], usage is called on the command type.

Provided Methods

fn command_name(&self) -> Option<&'static str>

Returns the name of a parsed command, if present.

This is implemented by derive(Options) in one of two ways:

• For struct types, if the type contains a field marked #[options(command)], this method is called on that value. Otherwise, None is returned.
• For enum types, the name corresponding to the variant is returned.

fn help_requested(&self) -> bool

Returns whether the user supplied a "help" option to request usage information about the program or any contained subcommands.

The default implementation returns false.

fn parse_args<S: AsRef<str>>(
    args: &[S],
    style: ParsingStyle
) -> Result<Self, Error>

Parses arguments received from the command line.

The first argument (the program name) should be omitted.

fn parse_args_or_exit(style: ParsingStyle) -> Self

Parses arguments from the environment.

If an error is encountered, the error is printed to stderr and the process will exit with status code 2.

If the user supplies a help option, option usage will be printed to stdout and the process will exit with status code 0.

Otherwise, the parsed options are returned.

fn parse_args_default_or_exit() -> Self

Parses arguments from the environment, using the default parsing style.

If an error is encountered, the error is printed to stderr and the process will exit with status code 2.

If the user supplies a help option, option usage will be printed to stdout and the process will exit with status code 0.

Otherwise, the parsed options are returned.

fn parse_args_default<S: AsRef<str>>(args: &[S]) -> Result<Self, Error>

Parses arguments received from the command line, using the default parsing style.

The first argument (the program name) should be omitted.

Implementors