Struct First 

pub struct First<T>(pub T);

A no-op merge that retains the first value.

This type provides a merge implementation that does nothing. Merging anything with a value of this type results in the other value getting discarded.

The opposite of this is Last.

Example

let a = First(vec![0, 1, 2]);
let b = First(vec![3, 4]);

let merged = a.merge(b).unwrap();

assert_eq!(*merged, &[0, 1, 2]);

serde

This type deserializes like T.

Tuple Fields

0: T

Trait Implementations

impl<T> AsMut<T> for First<T>

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

Converts this type into a mutable reference of the (usually inferred) input type.

impl<T> AsRef<T> for First<T>

fn as_ref(&self) -> &T

Converts this type into a shared reference of the (usually inferred) input type.

impl<T> Borrow<T> for First<T>

fn borrow(&self) -> &T

Immutably borrows from an owned value.

impl<T> BorrowMut<T> for First<T>

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

Mutably borrows from an owned value.

impl<T: Clone> Clone for First<T>

fn clone(&self) -> First<T>

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: Debug> Debug for First<T>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<T> Default for First<T>

where T: Default,

fn default() -> Self

Returns the “default value” for a type.

impl<T> Deref for First<T>

type Target = T

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<T> DerefMut for First<T>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<'de, T> Deserialize<'de> for First<T>

where T: Deserialize<'de>,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl<T> From<T> for First<T>

fn from(x: T) -> Self

Converts to this type from the input type.

impl<T: Hash> Hash for First<T>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<T> Merge for First<T>

fn merge_ref(&mut self, _: Self) -> Result<(), Error>

Merge self with other without taking ownership of self.

fn merge(self, other: Self) -> Result<Self, Error>

Merge self with other.

impl<T: Ord> Ord for First<T>

fn cmp(&self, other: &First<T>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<T: PartialEq> PartialEq for First<T>

fn eq(&self, other: &First<T>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<T: PartialOrd> PartialOrd for First<T>

fn partial_cmp(&self, other: &First<T>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<T: Copy> Copy for First<T>

impl<T: Eq> Eq for First<T>

impl<T> StructuralPartialEq for First<T>