1.0.0[−][src]Trait nom::lib::std::fmt::Debug

[+] Show declaration

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

[−]

? 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 (libstd, libcore, liballoc, 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.

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 };

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

Required methods

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

Formats the value using the given formatter.

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,
)");

1.0.0[−][src]Trait nom::lib::std::fmt::Debug

Stability

Examples

Required methods

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

Examples

Implementations on Foreign Types

impl Debug for Barrier[src][−]

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

impl<T> Debug for TryLockError<T>[src][−]

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

impl Debug for DirEntry[src][−]

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

impl Debug for PathBuf[src][−]

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result<(), Error>[src]

impl<T> Debug for Key<T>[src][−]

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

impl<T> Debug for RwLock<T> where T: Debug + ?Sized, [src][−]

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

impl Debug for Empty[src][−]

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

impl<W> Debug for IntoInnerError<W> where W: Debug, [src][−]

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

impl Debug for Stdio[src][−]

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

impl Debug for ChildStdin[src][−]

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

impl<'a> Debug for Ancestors<'a>[src][−]

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

impl Debug for Ipv4Addr[src][−]

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

impl<R> Debug for BufReader<R> where R: Debug, [src][−]

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

impl Debug for UnixStream[src][−]

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

impl<T> Debug for PoisonError<T>[src][−]

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

impl<B> Debug for Lines<B> where B: Debug, [src][−]

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

impl Debug for Path[src][−]

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result<(), Error>[src]

impl Debug for Output[src][−]

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

impl<'a> Debug for IoSlice<'a>[src][−]

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

impl Debug for FileType[src][−]

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

impl<T> Debug for Sender<T>[src][−]

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

impl Debug for TryRecvError[src][−]

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

impl<R> Debug for Bytes<R> where R: Debug, [src][−]

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

impl Debug for NulError[src][−]

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

impl Debug for FromBytesWithNulError[src][−]

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

impl Debug for BacktraceStatus[src][−]

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

impl Debug for Initializer[src][−]

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

impl<T> Debug for LocalKey<T> where T: 'static, [src][−]

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

impl Debug for Stdin[src][−]

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

impl<T> Debug for Key<T>[src][−]

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

impl Debug for Command[src][−]

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

impl<'a> Debug for Chain<'a>[src][−]

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

impl<'a> Debug for IoSliceMut<'a>[src][−]

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

impl Debug for UnixListener[src][−]

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

impl Debug for Args[src][−]

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

impl Debug for SocketAddr[src][−]

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

impl<W> Debug for LineWriter<W> where W: Write + Debug, [src][−]

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

`impl Debug for Barrier`[src][−]

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

`impl<T> Debug for TryLockError<T>`[src][−]

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

`impl Debug for DirEntry`[src][−]

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

`impl Debug for PathBuf`[src][−]

`fn fmt(&self, formatter: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl<T> Debug for Key<T>`[src][−]

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

`impl<T> Debug for RwLock<T> where T: Debug + ?Sized,` [src][−]

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

`impl Debug for Empty`[src][−]

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

`impl<W> Debug for IntoInnerError<W> where W: Debug,` [src][−]

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

`impl Debug for Stdio`[src][−]

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

`impl Debug for ChildStdin`[src][−]

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

`impl<'a> Debug for Ancestors<'a>`[src][−]

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

`impl Debug for Ipv4Addr`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl<R> Debug for BufReader<R> where R: Debug,` [src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for UnixStream`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl<T> Debug for PoisonError<T>`[src][−]

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

`impl<B> Debug for Lines<B> where B: Debug,` [src][−]

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

`impl Debug for Path`[src][−]

`fn fmt(&self, formatter: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for Output`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl<'a> Debug for IoSlice<'a>`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for FileType`[src][−]

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

`impl<T> Debug for Sender<T>`[src][−]

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

`impl Debug for TryRecvError`[src][−]

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

`impl<R> Debug for Bytes<R> where R: Debug,` [src][−]

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

`impl Debug for NulError`[src][−]

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

`impl Debug for FromBytesWithNulError`[src][−]

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

`impl Debug for BacktraceStatus`[src][−]

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

`impl Debug for Initializer`[src][−]

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

`impl<T> Debug for LocalKey<T> where T: 'static,` [src][−]

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

`impl Debug for Stdin`[src][−]

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

`impl<T> Debug for Key<T>`[src][−]

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

`impl Debug for Command`[src][−]

`fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>`[src][−]

`impl<'a> Debug for Chain<'a>`[src][−]

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

`impl<'a> Debug for IoSliceMut<'a>`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for UnixListener`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for Args`[src][−]

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

`impl Debug for SocketAddr`[src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl<W> Debug for LineWriter<W> where W: Write + Debug,` [src][−]

`fn fmt(&self, fmt: &mut Formatter<'_>) -> Result<(), Error>`[src]

`impl Debug for ChildStderr`[src][−]

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

`impl<'_> Debug for StdoutLock<'_>`[src][−]

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

`impl Debug for ThreadId`[src][−]