Trait nom::lib::std::fmt::Debug1.0.0[−][src]

pub trait Debug {
    pub 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

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

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,
)");

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

Stability

Examples

Required methods

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

Examples

Implementations on Foreign Types

impl Debug for Stdio[src]

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

impl Debug for IntoStringError[src]

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

impl<T> Debug for Key<T>[src]

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

impl Debug for Builder[src]

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

impl Debug for ExitCode[src]

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

impl Debug for OpenOptions[src]

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

impl<'a> Debug for Component<'a>[src]

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

impl Debug for AddrParseError[src]

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

impl Debug for ChildStderr[src]

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

impl Debug for TryRecvError[src]

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

impl Debug for FileType[src]

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

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

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

impl<T, U> Debug for Chain<T, U> where T: Debug, U: Debug, [src]

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

impl Debug for ReadDir[src]

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

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

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

impl<'a> Debug for CommandArgs<'a>[src]

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

impl Debug for ChildStdin[src]

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

impl<T> Debug for IntoIter<T> where T: Debug, [src]

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

impl Debug for Condvar[src]

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

impl Debug for UdpSocket[src]

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

impl Debug for Output[src]

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

impl<'_, T> Debug for RwLockWriteGuard<'_, T> where T: Debug, [src]

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

impl Debug for BacktraceStatus[src]

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

impl Debug for SocketAddrV6[src]

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

impl<'a, T> Debug for Iter<'a, T> where T: 'a + Debug, [src]

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

impl<'_> Debug for SplitPaths<'_>[src]

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

impl Debug for Child[src]

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

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

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

impl Debug for FromBytesWithNulError[src]

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

impl Debug for JoinPathsError[src]

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

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

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

impl Debug for Permissions[src]

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

impl Debug for SocketAddr[src]

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

impl Debug for ExitStatus[src]

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

impl Debug for Vars[src]

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

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

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

impl Debug for UnixStream[src]

Trait nom::lib::std::fmt::Debug1.0.0[−][src]

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

`impl Debug for Stdio`[src]

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

`impl Debug for IntoStringError`[src]

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

`impl<T> Debug for Key<T>`[src]

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

`impl Debug for Builder`[src]

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

`impl Debug for ExitCode`[src]

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

`impl Debug for OpenOptions`[src]

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

`impl<'a> Debug for Component<'a>`[src]

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

`impl Debug for AddrParseError`[src]

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

`impl Debug for ChildStderr`[src]

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

`impl Debug for TryRecvError`[src]

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

`impl Debug for FileType`[src]

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

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

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

`impl<T, U> Debug for Chain<T, U> where T: Debug, U: Debug,` [src]

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

`impl Debug for ReadDir`[src]

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

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

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

`impl<'a> Debug for CommandArgs<'a>`[src]

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

`impl Debug for ChildStdin`[src]

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

`impl<T> Debug for IntoIter<T> where T: Debug,` [src]

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

`impl Debug for Condvar`[src]

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

`impl Debug for UdpSocket`[src]

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

`impl Debug for Output`[src]

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

`impl<'_, T> Debug for RwLockWriteGuard<'_, T> where T: Debug,` [src]

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

`impl Debug for BacktraceStatus`[src]

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

`impl Debug for SocketAddrV6`[src]

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

`impl<'a, T> Debug for Iter<'a, T> where T: 'a + Debug,` [src]

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

`impl<'_> Debug for SplitPaths<'_>`[src]

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

`impl Debug for Child`[src]

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

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

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

`impl Debug for FromBytesWithNulError`[src]

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

`impl Debug for JoinPathsError`[src]

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

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

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

`impl Debug for Permissions`[src]

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

`impl Debug for SocketAddr`[src]

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

`impl Debug for ExitStatus`[src]

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

`impl Debug for Vars`[src]

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

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

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

`impl Debug for UnixStream`[src]

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

`impl Debug for Ipv6Addr`[src]

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

`impl Debug for AccessError`[src]

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