macro_rules! arg_enum {
(@as_item $($i:item)*) => { ... };
(@impls ( $($tts:tt)* ) -> ($e:ident, $($v:ident),+)) => { ... };
($(#[$($m:meta),+])+ pub enum $e:ident { $($v:ident $(=$val:expr)*,)+ } ) => { ... };
($(#[$($m:meta),+])+ pub enum $e:ident { $($v:ident $(=$val:expr)*),+ } ) => { ... };
($(#[$($m:meta),+])+ enum $e:ident { $($v:ident $(=$val:expr)*,)+ } ) => { ... };
($(#[$($m:meta),+])+ enum $e:ident { $($v:ident $(=$val:expr)*),+ } ) => { ... };
(pub enum $e:ident { $($v:ident $(=$val:expr)*,)+ } ) => { ... };
(pub enum $e:ident { $($v:ident $(=$val:expr)*),+ } ) => { ... };
(enum $e:ident { $($v:ident $(=$val:expr)*,)+ } ) => { ... };
(enum $e:ident { $($v:ident $(=$val:expr)*),+ } ) => { ... };
}
Expand description
Convenience macro to generate more complete enums with variants to be used as a type when
parsing arguments. This enum also provides a variants()
function which can be used to
retrieve a Vec<&'static str>
of the variant names, as well as implementing FromStr
and
Display
automatically.
NOTE: Case insensitivity is supported for ASCII characters only. It’s highly recommended to
use Arg::case_insensitive(true)
for args that will be used with these enums
NOTE: This macro automatically implements std::str::FromStr
and std::fmt::Display
NOTE: These enums support pub (or not) and uses of the #[derive()]
traits
Examples
arg_enum!{
#[derive(PartialEq, Debug)]
pub enum Foo {
Bar,
Baz,
Qux
}
}
// Foo enum can now be used via Foo::Bar, or Foo::Baz, etc
// and implements std::str::FromStr to use with the value_t! macros
fn main() {
let m = App::new("app")
.arg(Arg::from_usage("<foo> 'the foo'")
.possible_values(&Foo::variants())
.case_insensitive(true))
.get_matches_from(vec![
"app", "baz"
]);
let f = value_t!(m, "foo", Foo).unwrap_or_else(|e| e.exit());
assert_eq!(f, Foo::Baz);
}