Struct tracing::stdlib::fmt::DebugSet

1.2.0 · source ·
pub struct DebugSet<'a, 'b>
where 'b: 'a,
{ inner: DebugInner<'a, 'b>, }
Expand description

A struct to help with fmt::Debug implementations.

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

This can be constructed by the Formatter::debug_set 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_set().entries(self.0.iter()).finish()
    }
}

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

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§inner: DebugInner<'a, 'b>

Implementations§

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

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

Adds a new entry to the set 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_set()
           .entry(&self.0) // Adds the first "entry".
           .entry(&self.1) // Adds the second "entry".
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![10, 11], vec![12, 13])),
    "{[10, 11], [12, 13]}",
);
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pub fn entry_with<F>(&mut self, entry_fmt: F) -> &mut DebugSet<'a, 'b>
where F: FnOnce(&mut Formatter<'_>) -> Result<(), Error>,

🔬This is a nightly-only experimental API. (debug_closure_helpers #117729)

Adds a new entry to the set output.

This method is equivalent to DebugSet::entry, but formats the entry using a provided closure rather than by calling Debug::fmt.

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

Adds the contents of an iterator of entries to the set 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_set()
           .entries(self.0.iter()) // Adds the first "entry".
           .entries(self.1.iter()) // Adds the second "entry".
           .finish()
    }
}

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

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_set()
           .entries(self.0.iter())
           .finish() // Ends the set formatting.
    }
}

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

Auto Trait Implementations§

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impl<'a, 'b> Freeze for DebugSet<'a, 'b>

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

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

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

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impl<'a, 'b> Unpin for DebugSet<'a, 'b>

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

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more