# Struct alloc::fmt::DebugSet

1.2.0 · source · [−]

    pub struct DebugSet<'a, 'b>where
        'b: 'a,{ /* private fields */ }

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}",
    );

Run

## Implementations

source

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

source

#### 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]}",
    );

Run
source

#### 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}",
    );

Run
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 struct formatting.
        }
    }

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

Run

## Auto Trait Implementations

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

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

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

### impl<'a, 'b> Unpin for DebugSet<'a, 'b>where
'b: 'a,

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

## Blanket Implementations

source

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

source

#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
source

### impl<T> Borrow<T> for Twhere
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
source

### impl<T> BorrowMut<T> for Twhere
T: ?Sized,

const: unstable · source

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

Mutably borrows from an owned value. Read more
source

### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

source

### impl<T, U> Into<U> for Twhere
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

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

source

### impl<T, U> TryFrom<U> for Twhere
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
source

### impl<T, U> TryInto<U> for Twhere
U: TryFrom<T>,

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

The type returned in the event of a conversion error.
const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.