1.2.0[][src]Struct std::fmt::DebugTuple

#[must_use = "must eventually call `finish()` on Debug builders"]
pub struct DebugTuple<'a, 'b> where
    'b: 'a, 
{ /* fields omitted */ }

A struct to help with fmt::Debug implementations.

This is useful when you wish to output a formatted tuple as a part of your Debug::fmt implementation.

This can be constructed by the Formatter::debug_tuple method.

Examples

use std::fmt;

struct Foo(i32, String);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_tuple("Foo")
           .field(&self.0)
           .field(&self.1)
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(10, "Hello World".to_string())),
    "Foo(10, \"Hello World\")",
);Run

Methods

impl<'a, 'b> DebugTuple<'a, 'b> where
    'b: 'a, 
[src]

pub fn field(&mut self, value: &dyn Debug) -> &mut DebugTuple<'a, 'b>[src]

Adds a new field to the generated tuple struct output.

Examples

use std::fmt;

struct Foo(i32, String);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_tuple("Foo")
           .field(&self.0) // We add the first field.
           .field(&self.1) // We add the second field.
           .finish() // We're good to go!
    }
}

assert_eq!(
    format!("{:?}", Foo(10, "Hello World".to_string())),
    "Foo(10, \"Hello World\")",
);Run

pub fn finish(&mut self) -> Result<(), Error>[src]

Finishes output and returns any error encountered.

Examples

use std::fmt;

struct Foo(i32, String);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_tuple("Foo")
           .field(&self.0)
           .field(&self.1)
           .finish() // You need to call it to "finish" the
                     // tuple formatting.
    }
}

assert_eq!(
    format!("{:?}", Foo(10, "Hello World".to_string())),
    "Foo(10, \"Hello World\")",
);Run

Auto Trait Implementations

impl<'a, 'b> !UnwindSafe for DebugTuple<'a, 'b>

impl<'a, 'b> !RefUnwindSafe for DebugTuple<'a, 'b>

impl<'a, 'b> Unpin for DebugTuple<'a, 'b> where
    'b: 'a, 

impl<'a, 'b> !Send for DebugTuple<'a, 'b>

impl<'a, 'b> !Sync for DebugTuple<'a, 'b>

Blanket Implementations

impl<T> From<T> for T[src]

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = !

The type returned in the event of a conversion error.

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> Any for T where
    T: 'static + ?Sized
[src]