avail_rust_client::ext::scale_info::prelude::fmt

Trait 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,
)");

Debug

Trait Debug Copy item path

§Stability

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Debug for BalanceStatus

impl Debug for RuntimeCall

impl Debug for StoredState

impl Debug for BondExtraValue

impl Debug for ClaimPermission

impl Debug for ConfigOpAccount

impl Debug for PoolState

impl Debug for ProxyType

impl Debug for RewardDestination

impl Debug for ArithmeticError

impl Debug for DispatchError

impl Debug for Pays

impl Debug for TokenError

impl Debug for TransactionalError

impl Debug for Message

impl Debug for EncodeSelector

impl Debug for HashNumber

impl Debug for HeaderExtension

impl Debug for avail_rust_client::MultiAddress

impl Debug for avail_rust_client::RpcError

impl Debug for avail_rust_client::StorageHasher

impl Debug for avail_rust_client::error::Error

impl Debug for avail_rust_client::error::UserError

impl Debug for BlockState

impl Debug for MortalityOption

impl Debug for avail_rust_client::ext::const_hex::FromHexError

impl Debug for avail_rust_client::ext::primitive_types::Error

impl Debug for avail_rust_client::ext::subxt_core::alloc::collections::TryReserveErrorKind

impl Debug for avail_rust_client::ext::subxt_core::alloc::slice::GetDisjointMutError

impl Debug for SearchStep

impl Debug for BlockError

impl Debug for PolkadotConfig

impl Debug for SubstrateConfig

impl Debug for DigestItem

impl Debug for avail_rust_client::ext::subxt_core::config::substrate::NumberOrHex

impl Debug for CheckMetadataHashMode

impl Debug for avail_rust_client::ext::subxt_core::Error

impl Debug for ExtrinsicError

impl Debug for ExtrinsicParamsError

impl Debug for MetadataError

impl Debug for StorageAddressError

impl Debug for Phase

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_decode::error::ErrorKind

impl Debug for BitsOrderFormat

impl Debug for BitsStoreFormat

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_decode::ext::scale_type_resolver::Primitive

impl Debug for UnhandledKind

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_decode::ext::scale_type_resolver::portable_registry::Error

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_decode::visitor::DecodeError

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_decode::visitor::Unexpected

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_encode::error::ErrorKind

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_encode::error::Kind

impl Debug for avail_rust_client::ext::subxt_core::ext::scale_value::Primitive

impl Debug for TransactionVersion

impl Debug for avail_rust_client::ext::subxt_core::utils::bits::Lsb0

impl Debug for avail_rust_client::ext::subxt_core::utils::bits::Msb0

impl Debug for Era

impl Debug for avail_rust_client::ext::subxt_core::utils::MultiSignature

impl Debug for avail_rust_client::ext::subxt_rpcs::Error

impl Debug for ArchiveCallResult

impl Debug for MethodResponse

impl Debug for RuntimeEvent

impl Debug for StorageQueryType

impl Debug for StorageResultType

impl Debug for avail_rust_client::ext::subxt_rpcs::methods::legacy::NumberOrHex

impl Debug for AsciiChar

impl Debug for Infallible

impl Debug for FromBytesWithNulError

impl Debug for c_void

impl Debug for AtomicOrdering

impl Debug for avail_rust_client::ext::subxt_signer::bip39::core::net::IpAddr

Trait Debug