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//! An example of implementing Rust's standard formatting and parsing traits for flags types.
use core::{fmt, str};
bitflags::bitflags! {
// You can `#[derive]` the `Debug` trait, but implementing it manually
// can produce output like `A | B` instead of `Flags(A | B)`.
// #[derive(Debug)]
#[derive(PartialEq, Eq)]
pub struct Flags: u32 {
const A = 1;
const B = 2;
const C = 4;
const D = 8;
}
}
impl fmt::Debug for Flags {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
bitflags::parser::to_writer(self, f)
}
}
impl fmt::Display for Flags {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
bitflags::parser::to_writer(self, f)
}
}
impl str::FromStr for Flags {
type Err = bitflags::parser::ParseError;
fn from_str(flags: &str) -> Result<Self, Self::Err> {
bitflags::parser::from_str(flags)
}
}
fn main() -> Result<(), bitflags::parser::ParseError> {
let flags = Flags::A | Flags::B;
println!("{}", flags);
let formatted = flags.to_string();
let parsed: Flags = formatted.parse()?;
assert_eq!(flags, parsed);
Ok(())
}