Trait clap::FromArgMatches

source · 
pub trait FromArgMatches: Sized {
    fn from_arg_matches(
        matches: &ArgMatches
    ) -> Result<Self, Error<RichFormatter>>;
    fn update_from_arg_matches(
        &mut self,
        matches: &ArgMatches
    ) -> Result<(), Error<RichFormatter>>;

    fn from_arg_matches_mut(
        matches: &mut ArgMatches
    ) -> Result<Self, Error<RichFormatter>> { ... }
    fn update_from_arg_matches_mut(
        &mut self,
        matches: &mut ArgMatches
    ) -> Result<(), Error<RichFormatter>> { ... }
}
Expand description

Converts an instance of ArgMatches to a user-defined container.

Derived as part of Parser, Args, and Subcommand.

Required Methods§

Instantiate Self from ArgMatches, parsing the arguments as needed.

Motivation: If our application had two CLI options, --name <STRING> and the flag --debug, we may create a struct as follows:

struct Context {
    name: String,
    debug: bool
}

We then need to convert the ArgMatches that clap generated into our struct. from_arg_matches serves as the equivalent of:

impl From<ArgMatches> for Context {
   fn from(m: ArgMatches) -> Self {
       Context {
           name: m.get_one::<String>("name").unwrap().clone(),
           debug: m.get_flag("debug"),
       }
   }
}

Assign values from ArgMatches to self.

Provided Methods§

Instantiate Self from ArgMatches, parsing the arguments as needed.

Motivation: If our application had two CLI options, --name <STRING> and the flag --debug, we may create a struct as follows:

struct Context {
    name: String,
    debug: bool
}

We then need to convert the ArgMatches that clap generated into our struct. from_arg_matches_mut serves as the equivalent of:

impl From<ArgMatches> for Context {
   fn from(m: ArgMatches) -> Self {
       Context {
           name: m.get_one::<String>("name").unwrap().to_string(),
           debug: m.get_flag("debug"),
       }
   }
}

Assign values from ArgMatches to self.

Implementations on Foreign Types§

Implementors§