Struct frame_support::dispatch::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>

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>

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>

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)>,

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>

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))

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>

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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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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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fn borrow_mut(&mut self) -> &mut T

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impl<T> CheckedConversion for T

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fn checked_from<T>(t: T) -> Option<Self>where Self: TryFrom<T>,

Convert from a value of T into an equivalent instance of Option<Self>. Read more
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Consume self to return Some equivalent value of Option<T>. 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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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, Outer> IsWrappedBy<Outer> for Twhere Outer: AsRef<T> + AsMut<T> + From<T>, T: From<Outer>,

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fn from_ref(outer: &Outer) -> &T

Get a reference to the inner from the outer.

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fn from_mut(outer: &mut Outer) -> &mut T

Get a mutable reference to the inner from the outer.

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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> SaturatedConversion for T

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fn saturated_from<T>(t: T) -> Selfwhere Self: UniqueSaturatedFrom<T>,

Convert from a value of T into an equivalent instance of Self. Read more
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fn saturated_into<T>(self) -> Twhere Self: UniqueSaturatedInto<T>,

Consume self to return an equivalent value of T. Read more
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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.
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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 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.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<S, T> UncheckedInto<T> for Swhere T: UncheckedFrom<S>,

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fn unchecked_into(self) -> T

The counterpart to unchecked_from.
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impl<T, S> UniqueSaturatedInto<T> for Swhere T: Bounded, S: TryInto<T>,

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fn unique_saturated_into(self) -> T

Consume self to return an equivalent value of T.
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fn vzip(self) -> V

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impl<T> JsonSchemaMaybe for T