1.2.0[−][src]Struct std::fmt::DebugStruct
A struct to help with fmt::Debug
implementations.
This is useful when you wish to output a formatted struct as a part of your
Debug::fmt
implementation.
This can be constructed by the
Formatter::debug_struct
method.
Examples
use std::fmt; struct Foo { bar: i32, baz: String, } impl fmt::Debug for Foo { fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result { fmt.debug_struct("Foo") .field("bar", &self.bar) .field("baz", &self.baz) .finish() } } assert_eq!( format!("{:?}", Foo { bar: 10, baz: "Hello World".to_string() }), "Foo { bar: 10, baz: \"Hello World\" }", );Run
Methods
impl<'a, 'b> DebugStruct<'a, 'b> where
'b: 'a,
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'b: 'a,
pub fn field(
&mut self,
name: &str,
value: &dyn Debug
) -> &mut DebugStruct<'a, 'b>
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&mut self,
name: &str,
value: &dyn Debug
) -> &mut DebugStruct<'a, 'b>
Adds a new field to the generated struct output.
Examples
use std::fmt; struct Bar { bar: i32, another: String, } impl fmt::Debug for Bar { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fmt.debug_struct("Bar") .field("bar", &self.bar) // We add `bar` field. .field("another", &self.another) // We add `another` field. // We even add a field which doesn't exist (because why not?). .field("not_existing_field", &1) .finish() // We're good to go! } } assert_eq!( format!("{:?}", Bar { bar: 10, another: "Hello World".to_string() }), "Bar { bar: 10, another: \"Hello World\", not_existing_field: 1 }", );Run
pub fn finish(&mut self) -> Result<(), Error>
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Finishes output and returns any error encountered.
Examples
use std::fmt; struct Bar { bar: i32, baz: String, } impl fmt::Debug for Bar { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fmt.debug_struct("Bar") .field("bar", &self.bar) .field("baz", &self.baz) .finish() // You need to call it to "finish" the // struct formatting. } } assert_eq!( format!("{:?}", Bar { bar: 10, baz: "Hello World".to_string() }), "Bar { bar: 10, baz: \"Hello World\" }", );Run
Auto Trait Implementations
impl<'a, 'b> !Send for DebugStruct<'a, 'b>
impl<'a, 'b> !Sync for DebugStruct<'a, 'b>
Blanket Implementations
impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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ⓘImportant traits for &'_ mut F
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,