pub trait Parser: FromArgMatches + CommandFactory + Sized {
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,
{ ... }
}
Expand description
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
.
See the derive reference for attributes and best practices.
NOTE: Deriving requires the [derive
feature flag][crate::_features]
Examples
The following example creates a Context
struct that would be used
throughout the application representing the normalized values coming from
the CLI.
/// My super CLI
#[derive(clap::Parser)]
#[clap(name = "demo")]
struct Context {
/// More verbose output
#[clap(long)]
verbose: bool,
/// An optional name
#[clap(short, long)]
name: Option<String>,
}
The equivalent Command
struct + From
implementation:
Command::new("demo")
.about("My super CLI")
.arg(Arg::new("verbose")
.long("verbose")
.action(ArgAction::SetTrue)
.help("More verbose output"))
.arg(Arg::new("name")
.long("name")
.short('n')
.help("An optional name")
.takes_value(true));
struct Context {
verbose: bool,
name: Option<String>,
}
impl From<ArgMatches> for Context {
fn from(m: ArgMatches) -> Self {
Context {
verbose: *m.get_one::<bool>("verbose").expect("defaulted_by_clap"),
name: m.get_one::<String>("name").cloned(),
}
}
}
Provided Methods§
sourcefn parse_from<I, T>(itr: I) -> Selfwhere
I: IntoIterator<Item = T>,
T: Into<OsString> + Clone,
fn parse_from<I, T>(itr: I) -> Selfwhere
I: IntoIterator<Item = T>,
T: Into<OsString> + Clone,
Parse from iterator, exit on error
sourcefn try_parse_from<I, T>(itr: I) -> Result<Self, Error>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,
Parse from iterator, return Err on error.
sourcefn update_from<I, T>(&mut self, itr: I)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,
Update from iterator, exit on error
sourcefn try_update_from<I, T>(&mut self, itr: I) -> Result<(), Error>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,
Update from iterator, return Err on error.