1 //! An example of implementing Rust's standard formatting and parsing traits for flags types.
2
3 use core::{fmt, str};
4
5 bitflags::bitflags! {
6 // You can `#[derive]` the `Debug` trait, but implementing it manually
7 // can produce output like `A | B` instead of `Flags(A | B)`.
8 // #[derive(Debug)]
9 #[derive(PartialEq, Eq)]
10 pub struct Flags: u32 {
11 const A = 1;
12 const B = 2;
13 const C = 4;
14 const D = 8;
15 }
16 }
17
18 impl fmt::Debug for Flags {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result19 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
20 bitflags::parser::to_writer(self, f)
21 }
22 }
23
24 impl fmt::Display for Flags {
fmt(&self, f: &mut fmt::Formatter) -> fmt::Result25 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
26 bitflags::parser::to_writer(self, f)
27 }
28 }
29
30 impl str::FromStr for Flags {
31 type Err = bitflags::parser::ParseError;
32
from_str(flags: &str) -> Result<Self, Self::Err>33 fn from_str(flags: &str) -> Result<Self, Self::Err> {
34 bitflags::parser::from_str(flags)
35 }
36 }
37
main() -> Result<(), bitflags::parser::ParseError>38 fn main() -> Result<(), bitflags::parser::ParseError> {
39 let flags = Flags::A | Flags::B;
40
41 println!("{}", flags);
42
43 let formatted = flags.to_string();
44 let parsed: Flags = formatted.parse()?;
45
46 assert_eq!(flags, parsed);
47
48 Ok(())
49 }
50