devela::_core::fmt

Trait Display

1.6.0 · 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, }),
);

Implementors§

1.0.0 · Source§

impl Display for VarError

1.15.0 · Source§

impl Display for RecvTimeoutError

1.0.0 · Source§

impl Display for Colored

Trait DisplayCopy item path

§Internationalization

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Display for VarError

impl Display for RecvTimeoutError

impl Display for TryRecvError

impl Display for CheckedCastError

impl Display for PodCastError

impl Display for SetCursorStyle

impl Display for KeyCode

impl Display for MediaKeyCode

impl Display for ModifierKeyCode

impl Display for Attribute

impl Display for Colored

impl Display for devela::_dep::kira::backend::cpal::Error

impl Display for FromFileError

impl Display for devela::_dep::log::Level

impl Display for devela::_dep::log::LevelFilter

impl Display for ConnectErrorKind

impl Display for PortInfoError

impl Display for devela::_dep::midir::SendError

impl Display for ShaderError

impl Display for devela::_dep::miniquad::fs::Error

impl Display for Associativity

impl Display for CacheType

impl Display for DatType

impl Display for ExtendedRegisterStateLocation

impl Display for ExtendedRegisterType

impl Display for TopologyType

impl Display for Panic

impl Display for BuildStreamError

impl Display for DefaultStreamConfigError

impl Display for DeviceNameError

impl Display for PauseStreamError

impl Display for PlayStreamError

impl Display for SampleFormat

impl Display for devela::_dep::rodio::cpal::StreamError

impl Display for SupportedStreamConfigsError

impl Display for DecoderError

impl Display for Mp4Type

impl Display for devela::_dep::rodio::decoder::symphonia::SeekError

impl Display for DevicesError

impl Display for PlayError

impl Display for devela::_dep::rodio::StreamError

impl Display for devela::_dep::rodio::source::SeekError

impl Display for devela::_dep::symphonia::core::errors::Error

impl Display for Value

impl Display for DiskKind

impl Display for ProcessStatus

impl Display for Signal

impl Display for devela::_dep::winnow::error::ErrorKind

impl Display for StrContext

impl Display for StrContextValue

impl Display for AudioError

impl Display for ColorError

impl Display for DrawError

impl Display for FontError

impl Display for ImageError

impl Display for devela::all::IoErrorKind

impl Display for MediaError

impl Display for MidiError

impl Display for NotAvailable

impl Display for Infallible

impl Display for DataNotEnough

impl Display for MismatchedBounds

impl Display for PartialSpace

impl Display for NumError

impl Display for Month

impl Display for Weekday

impl Display for devela::text::AsciiChar

impl Display for InvalidText

impl Display for devela::ui::LayoutError

impl Display for UiError

impl Display for devela::_core::ascii::Char

impl Display for IpAddr

Trait Display