Struct kvarn::prelude::fmt::DebugMap

1.2.0 · source ·
pub struct DebugMap<'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 map as a part of your Debug::fmt implementation.

This can be constructed by the Formatter::debug_map method.

Examples

use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_map().entries(self.0.iter().map(|&(ref k, ref v)| (k, v))).finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"A\": 10, \"B\": 11}",
);

Implementations§

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

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

Available on non-crate feature miri-test-libstd only.

Adds a new entry to the map output.

Examples
use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_map()
           .entry(&"whole", &self.0) // We add the "whole" entry.
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"whole\": [(\"A\", 10), (\"B\", 11)]}",
);
1.42.0 · source

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

Available on non-crate feature miri-test-libstd only.

Adds the key part of a new entry to the map output.

This method, together with value, is an alternative to entry that can be used when the complete entry isn’t known upfront. Prefer the entry method when it’s possible to use.

Panics

key must be called before value and each call to key must be followed by a corresponding call to value. Otherwise this method will panic.

Examples
use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_map()
           .key(&"whole").value(&self.0) // We add the "whole" entry.
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"whole\": [(\"A\", 10), (\"B\", 11)]}",
);
1.42.0 · source

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

Available on non-crate feature miri-test-libstd only.

Adds the value part of a new entry to the map output.

This method, together with key, is an alternative to entry that can be used when the complete entry isn’t known upfront. Prefer the entry method when it’s possible to use.

Panics

key must be called before value and each call to key must be followed by a corresponding call to value. Otherwise this method will panic.

Examples
use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_map()
           .key(&"whole").value(&self.0) // We add the "whole" entry.
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"whole\": [(\"A\", 10), (\"B\", 11)]}",
);
source

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

Available on non-crate feature miri-test-libstd only.

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

Examples
use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_map()
           // We map our vec so each entries' first field will become
           // the "key".
           .entries(self.0.iter().map(|&(ref k, ref v)| (k, v)))
           .finish()
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"A\": 10, \"B\": 11}",
);
source

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

Available on non-crate feature miri-test-libstd only.

Finishes output and returns any error encountered.

Panics

key must be called before value and each call to key must be followed by a corresponding call to value. Otherwise this method will panic.

Examples
use std::fmt;

struct Foo(Vec<(String, i32)>);

impl fmt::Debug for Foo {
    fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
        fmt.debug_map()
           .entries(self.0.iter().map(|&(ref k, ref v)| (k, v)))
           .finish() // Ends the struct formatting.
    }
}

assert_eq!(
    format!("{:?}", Foo(vec![("A".to_string(), 10), ("B".to_string(), 11)])),
    "{\"A\": 10, \"B\": 11}",
);

Trait Implementations§

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impl<'a, 'b> Visit for DebugMap<'a, 'b>

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fn record_debug(&mut self, field: &Field, value: &dyn Debug)

Visit a value implementing fmt::Debug.
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fn record_f64(&mut self, field: &Field, value: f64)

Visit a double-precision floating point value.
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fn record_i64(&mut self, field: &Field, value: i64)

Visit a signed 64-bit integer value.
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fn record_u64(&mut self, field: &Field, value: u64)

Visit an unsigned 64-bit integer value.
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fn record_i128(&mut self, field: &Field, value: i128)

Visit a signed 128-bit integer value.
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fn record_u128(&mut self, field: &Field, value: u128)

Visit an unsigned 128-bit integer value.
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fn record_bool(&mut self, field: &Field, value: bool)

Visit a boolean value.
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fn record_str(&mut self, field: &Field, value: &str)

Visit a string value.
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fn record_error(&mut self, field: &Field, value: &(dyn Error + 'static))

Available on crate feature std only.
Records a type implementing Error.

Auto Trait Implementations§

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

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

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

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impl<'a, 'b> Unpin for DebugMap<'a, 'b>where 'b: 'a,

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

Blanket Implementations§

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

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<'a, T, E> AsTaggedExplicit<'a, E> for Twhere T: 'a,

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fn explicit(self, class: Class, tag: u32) -> TaggedParser<'a, Explicit, Self, E>

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impl<'a, T, E> AsTaggedImplicit<'a, E> for Twhere T: 'a,

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fn implicit( self, class: Class, constructed: bool, tag: u32 ) -> TaggedParser<'a, Implicit, Self, E>

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

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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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
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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 Twhere 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> Pointable for T

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const ALIGN: usize = mem::align_of::<T>()

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same<T> for T

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type Output = T

Should always be Self
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impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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

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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.
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impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

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fn vzip(self) -> V

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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