Trait xcm_emulator::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,
)");

Trait xcm_emulator::DebugCopy item path

§Stability

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Debug for xcm_emulator::AggregateMessageOrigin

impl Debug for xcm_emulator::CumulusAggregateMessageOrigin

impl Debug for ExecuteOverweightError

impl Debug for ProcessMessageError

impl Debug for UmpQueueId

impl Debug for xcm_emulator::WeightLimit

impl Debug for xcm_emulator::fmt::Alignment

impl Debug for TryReserveErrorKind

impl Debug for AsciiChar

impl Debug for core::cmp::Ordering

impl Debug for Infallible

impl Debug for c_void

impl Debug for IpAddr

impl Debug for Ipv6MulticastScope

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

impl Debug for FpCategory

impl Debug for IntErrorKind

impl Debug for SearchStep

impl Debug for core::sync::atomic::Ordering

impl Debug for BacktraceStatus

impl Debug for VarError

impl Debug for SeekFrom

impl Debug for std::io::error::ErrorKind

impl Debug for Shutdown

impl Debug for AncillaryError

impl Debug for BacktraceStyle

impl Debug for RecvTimeoutError

impl Debug for std::sync::mpsc::TryRecvError

impl Debug for _Unwind_Reason_Code

impl Debug for AhoCorasickKind

impl Debug for aho_corasick::packed::api::MatchKind

impl Debug for aho_corasick::util::error::MatchErrorKind

impl Debug for aho_corasick::util::prefilter::Candidate

impl Debug for aho_corasick::util::search::Anchored

impl Debug for aho_corasick::util::search::MatchKind

impl Debug for StartKind

impl Debug for Colour

impl Debug for array_bytes::Error

impl Debug for base16ct::error::Error

impl Debug for DecodeError

impl Debug for CharacterSet

impl Debug for base64ct::errors::Error

impl Debug for LineEnding

impl Debug for bs58::alphabet::Error

impl Debug for bs58::decode::Error

impl Debug for bs58::encode::Error

impl Debug for byte_slice_cast::Error

impl Debug for byteorder::BigEndian

impl Debug for byteorder::LittleEndian

impl Debug for Colons

impl Debug for Fixed

impl Debug for Numeric

impl Debug for OffsetPrecision

impl Debug for Pad

impl Debug for ParseErrorKind

impl Debug for SecondsFormat

impl Debug for Month

impl Debug for RoundingError

impl Debug for Weekday

impl Debug for const_oid::error::Error

impl Debug for cumulus_pallet_parachain_system::relay_state_snapshot::Error

impl Debug for ReadEntryErr

impl Debug for CumulusDigestItem

impl Debug for MessageSendError

impl Debug for ServiceQuality

impl Debug for der::error::ErrorKind

impl Debug for der::tag::class::Class

impl Debug for der::tag::Tag

impl Debug for TagMode

impl Debug for TruncSide

impl Debug for ed25519_zebra::error::Error

impl Debug for frame_election_provider_support::onchain::Error

Trait xcm_emulator::Debug