Trait bones_framework::asset::prelude::bones_utils::prelude::alloc::fmt::Debug

1.0.0 · source ·

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

Expand description

? formatting.

Debug should format the output in a programmer-facing, debugging context.

Generally speaking, you should just derive a Debug implementation.

When used with the alternate format specifier #?, the output is pretty-printed.

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

This trait can be used with #[derive] if all fields implement Debug. When derived for structs, it will use the name of the struct, then {, then a comma-separated list of each field’s name and Debug value, then }. For enums, it will use the name of the variant and, if applicable, (, then the Debug values of the fields, then ).

§Stability

Derived Debug formats are not stable, and so may change with future Rust versions. Additionally, Debug implementations of types provided by the standard library (std, core, alloc, etc.) are not stable, and may also change with future Rust versions.

§Examples

Deriving an implementation:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

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

assert_eq!(
    format!("The origin is: {origin:?}"),
    "The origin is: Point { x: 0, y: 0 }",
);

Manually implementing:

use std::fmt;

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

impl fmt::Debug for Point {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("Point")
         .field("x", &self.x)
         .field("y", &self.y)
         .finish()
    }
}

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

assert_eq!(
    format!("The origin is: {origin:?}"),
    "The origin is: Point { x: 0, y: 0 }",
);

There are a number of helper methods on the Formatter struct to help you with manual implementations, such as debug_struct.

Types that do not wish to use the standard suite of debug representations provided by the Formatter trait (debug_struct, debug_tuple, debug_list, debug_set, debug_map) can do something totally custom by manually writing an arbitrary representation to the Formatter.

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

Debug implementations using either derive or the debug builder API on Formatter support pretty-printing using the alternate flag: {:#?}.

Pretty-printing with #?:

#[derive(Debug)]
struct Point {
    x: i32,
    y: i32,
}

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

let expected = "The origin is: Point {
    x: 0,
    y: 0,
}";
assert_eq!(format!("The origin is: {origin:#?}"), expected);

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::Debug for Position {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_tuple("")
         .field(&self.longitude)
         .field(&self.latitude)
         .finish()
    }
}

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

assert_eq!(format!("{position:#?}"), "(
    1.987,
    2.983,
)");

source §

impl Debug for EndOfInput

source §

impl Debug for untrusted::reader::Reader<'_>

Avoids writing the value or position to avoid creating a side channel, though Reader can’t avoid leaking the position via timing.

Debug the serialization of this URL.

impl Debug for Event

§

impl Debug for Event

When the alternate flag is enabled this will print platform specific details, for example the fields of the kevent structure on platforms that use kqueue(2). Note however that the output of this implementation is not consider a part of the stable API.

let rasterizer = ab_glyph_rasterizer::Rasterizer::new(3, 4);
assert_eq!(
    &format!("{:?}", rasterizer),
    "Rasterizer { width: 3, height: 4 }"
);

Styles have a special Debug implementation that only shows the fields that are set. Fields that haven’t been touched aren’t included in the output.

This behaviour gets bypassed when using the alternate formatting mode format!("{:#?}").

use nu_ansi_term::Color::{Red, Blue};
assert_eq!("Style { fg(Red), on(Blue), bold, italic }",
           format!("{:?}", Red.on(Blue).bold().italic()));

This trait is implemented for tuples up to twelve items long.

impl<T, O> Debug for BitVec<T, O>
where T: BitStore, O: BitOrder,

§

impl<T, O> Debug for Drain<'_, T, O>
where T: BitStore, O: BitOrder,

§

impl<T, O> Debug for IntoIter<T, O>
where T: BitStore, O: BitOrder,

Original

§

impl<T, O> Debug for Iter<'_, T, O>
where T: BitStore, O: BitOrder,

Original

§

impl<T, O> Debug for IterMut<'_, T, O>
where T: BitStore, O: BitOrder,

impl<const SIZE: usize> Debug for EcdsaPrivateKey<SIZE>

§

Trait bones_framework::asset::prelude::bones_utils::prelude::alloc::fmt::DebugCopy item path

§Stability

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Debug for AudioEvent

impl Debug for MatchmakerRequest

impl Debug for MatchmakerResponse

impl Debug for TargetClient

impl Debug for DesyncDetection

impl Debug for GgrsError

impl Debug for InputStatus

impl Debug for SessionState

impl Debug for bones_framework::glam::EulerRot

impl Debug for ButtonState

impl Debug for GamepadAxis

impl Debug for GamepadButton

impl Debug for GamepadConnectionEventKind

impl Debug for GamepadEvent

impl Debug for GamepadRumbleRequest

impl Debug for KeyCode

impl Debug for MouseButton

impl Debug for MouseScrollUnit

impl Debug for CoreStage

impl Debug for QuerySingleError

impl Debug for LogFileError

impl Debug for NetworkInputStatus

impl Debug for LanMatchmakerRequest

impl Debug for OnlineMatchmakerRequest

impl Debug for OnlineMatchmakerResponse

impl Debug for EcsRefBorrowError

impl Debug for CompileErrorKind

impl Debug for ParseErrorKind

impl Debug for LexError

impl Debug for BinaryOperator

impl Debug for UnaryOperator

impl Debug for ClosureError

impl Debug for ExecutorMode

impl Debug for InvalidTableKey

impl Debug for MetaMethod

impl Debug for PrototypeError

impl Debug for StashedFunction

impl Debug for StaticError

impl Debug for StaticValue

impl Debug for ThreadMode

impl Debug for VMError

impl Debug for Operation

impl Debug for RCIndex

impl Debug for BinaryOperatorError

impl Debug for UpValueDescriptor

impl Debug for CameraSize

impl Debug for bones_framework::render::color::Color

impl Debug for HexColorError

impl Debug for bones_framework::render::sprite::Image

impl Debug for TimerMode

impl Debug for EnumTagType

impl Debug for bones_framework::asset::Primitive

impl Debug for SchemaKind

impl Debug for SchemaRefAccess<'_>

impl Debug for SchemaRefMutAccess<'_>

impl Debug for CollectionAllocErr

impl Debug for LabeledIdCreateError

impl Debug for LabledIdParseError

impl Debug for bones_framework::asset::prelude::bones_utils::prelude::futures::io::ErrorKind

impl Debug for SeekFrom

impl Debug for bones_framework::asset::prelude::bones_utils::prelude::hashbrown::TryReserveError

impl Debug for bones_framework::asset::prelude::bones_utils::prelude::parking_lot::OnceState

impl Debug for TryReserveErrorKind

impl Debug for SearchStep

impl Debug for bones_framework::asset::prelude::bones_utils::prelude::alloc::fmt::Alignment

impl Debug for AsciiChar

impl Debug for core::cmp::Ordering

impl Debug for Infallible

impl Debug for c_void

impl Debug for core::net::ip_addr::IpAddr

impl Debug for Ipv6MulticastScope

impl Debug for core::net::socket_addr::SocketAddr

Trait bones_framework::asset::prelude::bones_utils::prelude::alloc::fmt::Debug