gstd::prelude::fmt

Trait Display

1.0.0 · Source

pub trait Display {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}

Expand description

Format trait for an empty format, {}.

Implementing this trait for a type will automatically implement the ToString trait for the type, allowing the usage of the .to_string() method. Prefer implementing the Display trait for a type, rather than ToString.

Display is similar to Debug, but Display is for user-facing output, and so cannot be derived.

For more information on formatters, see the module-level documentation.

§Internationalization

Because a type can only have one Display implementation, it is often preferable to only implement Display when there is a single most “obvious” way that values can be formatted as text. This could mean formatting according to the “invariant” culture and “undefined” locale, or it could mean that the type display is designed for a specific culture/locale, such as developer logs.

If not all values have a justifiably canonical textual format or if you want to support alternative formats not covered by the standard set of possible formatting traits, the most flexible approach is display adapters: methods like str::escape_default or Path::display which create a wrapper implementing Display to output the specific display format.

§Examples

Implementing Display on a type:

use std::fmt;

struct Point {
    x: i32,
    y: i32,
}

impl fmt::Display for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.x, self.y)
    }
}

let origin = Point { x: 0, y: 0 };

assert_eq!(format!("The origin is: {origin}"), "The origin is: (0, 0)");

Required Methods§

1.0.0 · Source

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

§Examples

use std::fmt;

struct Position {
    longitude: f32,
    latitude: f32,
}

impl fmt::Display for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "({}, {})", self.longitude, self.latitude)
    }
}

assert_eq!(
    "(1.987, 2.983)",
    format!("{}", Position { longitude: 1.987, latitude: 2.983, }),
);

Trait DisplayCopy item path

§Internationalization

§Examples

Required Methods§

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

§Errors

§Examples

Implementors§

impl Display for ConversionError

impl Display for gstd::errors::CoreError

impl Display for gstd::errors::Error

impl Display for ErrorReplyReason

impl Display for ExecutionError

impl Display for ExtError

impl Display for MemoryError

impl Display for MessageError

impl Display for ReplyCode

impl Display for ReservationError

impl Display for SignalCode

impl Display for SimpleExecutionError

impl Display for SimpleUnavailableActorError

impl Display for SuccessReplyReason

impl Display for UsageError

impl Display for AsciiChar

impl Display for Infallible

impl Display for FromBytesWithNulError

impl Display for GetDisjointMutError

impl Display for IpAddr

impl Display for SocketAddr

impl Display for bs58::alphabet::Error

impl Display for bs58::decode::Error

impl Display for bs58::encode::Error

impl Display for byte_slice_cast::Error

impl Display for gear_ss58::Error

impl Display for ByteSliceFormatter<'_>

impl Display for hex::error::FromHexError

impl Display for rustc_hex::FromHexError

impl Display for FromDecStrErr

impl Display for bool

impl Display for char

impl Display for f32

impl Display for f64

impl Display for i8

impl Display for i16

impl Display for i32

impl Display for i64

impl Display for i128

impl Display for isize

impl Display for !

impl Display for str

impl Display for u8

impl Display for u16

impl Display for u32

impl Display for u64

impl Display for u128

impl Display for usize

impl Display for gstd::errors::CodecError

impl Display for ErrorReplyPayload

impl Display for ActorId

impl Display for CodeId

impl Display for MessageId

impl Display for ReservationId

impl Display for Ss58Address

impl Display for TryFromSliceError

impl Display for gstd::prelude::ascii::EscapeDefault

impl Display for BorrowError

impl Display for BorrowMutError

impl Display for CharTryFromError

impl Display for DecodeUtf16Error

impl Display for gstd::prelude::char::EscapeDebug

impl Display for gstd::prelude::char::EscapeDefault

impl Display for gstd::prelude::char::EscapeUnicode

impl Display for ParseCharError

impl Display for ToLowercase

impl Display for ToUppercase

impl Display for TryFromCharError

impl Display for UnorderedKeyError

impl Display for TryReserveError

impl Display for FromBytesUntilNulError

impl Display for FromVecWithNulError

Trait Display

impl<'a, K, V, A> Display for gstd::prelude::collections::btree_map::OccupiedError<'a, K, V, A>
where K: Debug + Ord, V: Debug, A: Allocator + Clone,

impl<'a, K, V, S, A> Display for gstd::prelude::collections::hash_map::OccupiedError<'a, K, V, S, A>
where K: Debug, V: Debug, A: Allocator,

impl<B> Display for Cow<'_, B>
where B: Display + ToOwned + ?Sized, <B as ToOwned>::Owned: Display,

impl<F> Display for FromFn<F>
where F: Fn(&mut Formatter<'_>) -> Result<(), Error>,

impl<Ptr> Display for Pin<Ptr>
where Ptr: Display,

impl<T> Display for &T
where T: Display + ?Sized,

impl<T> Display for &mut T
where T: Display + ?Sized,

impl<T> Display for ThinBox<T>
where T: Display + ?Sized,

impl<T> Display for gstd::prelude::cell::Ref<'_, T>
where T: Display + ?Sized,

impl<T> Display for RefMut<'_, T>
where T: Display + ?Sized,

impl<T> Display for NonZero<T>
where T: ZeroablePrimitive + Display,

impl<T> Display for Saturating<T>
where T: Display,