llm_tools::ser::core::fmt

Trait Debug

1.6.0 · 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 DebugCopy item path

§Stability

§Examples

Required Methods§

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

§Errors

§Examples

Implementors§

impl Debug for llm_tools::secret::Error

impl Debug for AsciiChar

impl Debug for llm_tools::ser::core::cmp::Ordering

impl Debug for Infallible

impl Debug for FromBytesWithNulError

impl Debug for c_void

impl Debug for llm_tools::ser::core::net::IpAddr

impl Debug for Ipv6MulticastScope

impl Debug for llm_tools::ser::core::net::SocketAddr

impl Debug for FpCategory

impl Debug for IntErrorKind

impl Debug for llm_tools::ser::core::slice::GetDisjointMutError

impl Debug for SearchStep

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

impl Debug for llm_tools::ser::core::fmt::Alignment

impl Debug for DebugAsHex

impl Debug for Sign

impl Debug for TryReserveErrorKind

impl Debug for BacktraceStatus

impl Debug for VarError

impl Debug for std::fs::TryLockError

impl Debug for SeekFrom

impl Debug for 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 ParseAlphabetError

impl Debug for base64::decode::DecodeError

impl Debug for DecodeSliceError

impl Debug for EncodeSliceError

impl Debug for DecodePaddingMode

impl Debug for byteorder::BigEndian

impl Debug for byteorder::LittleEndian

impl Debug for BitOrder

impl Debug for DecodeKind

impl Debug for TruncSide

impl Debug for dotenv::errors::Error

impl Debug for CoderResult

impl Debug for DecoderResult

impl Debug for EncoderResult

impl Debug for Latin1Bidi

impl Debug for LineType

impl Debug for PollNext

impl Debug for hashbrown::TryReserveError

impl Debug for httparse::Error

impl Debug for TrieResult

impl Debug for InvalidStringList

impl Debug for TrieType

impl Debug for icu_collections::codepointtrie::error::Error

impl Debug for ExtensionType

impl Debug for icu_locale_core::parser::errors::ParseError

impl Debug for PreferencesParseError

impl Debug for Decomposed

impl Debug for BidiPairedBracketType

impl Debug for GeneralCategory

impl Debug for BufferFormat

impl Debug for DataErrorKind

impl Debug for ProcessingError

impl Debug for ProcessingSuccess

impl Debug for indexmap::GetDisjointMutError

impl Debug for IpAddrRange

impl Debug for IpNet

impl Debug for IpSubnets

impl Debug for IriSpec

impl Debug for UriSpec

impl Debug for VisitPurpose

impl Debug for iri_string::template::simple_context::Value

impl Debug for log::Level

impl Debug for log::LevelFilter

impl Debug for PrefilterConfig

Trait Debug