Struct std::fmt::DebugList
pub struct DebugList<'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 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]",
);Implementations
impl<'a, 'b> DebugList<'a, 'b> where
'b: 'a,
pub fn entry(&mut self, entry: &dyn Debug) -> &mut DebugList<'a, 'b>
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]]",
);pub fn entries<D, I>(&mut self, entries: I) -> &mut DebugList<'a, 'b> where
I: IntoIterator<Item = D>,
D: Debug,
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]",
);pub fn finish(&mut self) -> Result<(), Error>
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]",
);Auto Trait Implementations
impl<'a, 'b> !RefUnwindSafe for DebugList<'a, 'b>
impl<'a, 'b> !Send for DebugList<'a, 'b>
impl<'a, 'b> !Sync for DebugList<'a, 'b>
impl<'a, 'b> Unpin for DebugList<'a, 'b> where
'b: 'a,
impl<'a, 'b> !UnwindSafe for DebugList<'a, 'b>
Blanket Implementations
impl<T> From<T> for T
pub fn from(t: T) -> T
Performs the conversion.
pub fn into(self) -> U
Performs the conversion.
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/fmt/struct.DebugList.html