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()
    }
}

// prints "[10, 11]"
println!("{:?}", Foo(vec![10, 11]));

Methods

impl<'a, 'b> DebugList<'a, 'b> where     'b: 'a,

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

Adds a new entry to the list output.

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

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

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

Finishes output and returns any error encountered.