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

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

A struct to help with fmt::Debug implementations.

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

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

Examples

use std::fmt;

struct Foo(Vec<i32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_list().entries(self.0.iter()).finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11])),
    "[10, 11]",
);Run

Methods

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

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

Adds a new entry to the list output.

Examples

use std::fmt;

struct Foo(Vec<i32>, Vec<u32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_list()
           .entry(&self.0) // We add the first "entry".
           .entry(&self.1) // We add the second "entry".
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
    "[[10, 11], [12, 13]]",
);Run

pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugList<'a, 'b> where
    D: Debug,
    I: IntoIterator<Item = D>, 
[src]

Adds the contents of an iterator of entries to the list output.

Examples

use std::fmt;

struct Foo(Vec<i32>, Vec<u32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_list()
           .entries(self.0.iter())
           .entries(self.1.iter())
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
    "[10, 11, 12, 13]",
);Run

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

Finishes output and returns any error encountered.

Examples

use std::fmt;

struct Foo(Vec<i32>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_list()
           .entries(self.0.iter())
           .finish() // Ends the struct formatting.
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11])),
    "[10, 11]",
);Run

Auto Trait Implementations

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

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

Blanket Implementations

impl<T> From for T[src]

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

type Error = Infallible

The type returned in the event of a conversion error.

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

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

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

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