Struct First 

pub struct First<A>(pub A);

A newtype wrapper whose Semigroup instance always keeps the first value.

append(First(a), First(b)) returns First(a), discarding b.

There is no Monoid instance because there is no identity element.

Examples

use fp_library::{
	functions::*,
	types::First,
};

assert_eq!(append(First("hello"), First("world")), First("hello"));

Tuple Fields

0: A

The wrapped value.

Trait Implementations

impl<A: Clone> Clone for First<A>

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

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<A: Debug> Debug for First<A>

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

Formats the value using the given formatter.

impl<A: Default> Default for First<A>

fn default() -> First<A>

Returns the “default value” for a type.

impl<A: Hash> Hash for First<A>

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<A: Ord> Ord for First<A>

fn cmp(&self, other: &First<A>) -> 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<A: PartialEq> PartialEq for First<A>

fn eq(&self, other: &First<A>) -> 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<A: PartialOrd> PartialOrd for First<A>

fn partial_cmp(&self, other: &First<A>) -> 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<A> Semigroup for First<A>

Type Parameters

• A: The wrapped type.

fn append(a: Self, _b: Self) -> Self

Returns the first (leftmost) value, discarding the second.

Type Signature

forall A. (First A, First A) -> First A

Parameters

• a: The first value (kept).
• _b: The second value (discarded).

Returns

The first value.

Examples

use fp_library::{
	functions::*,
	types::First,
};

assert_eq!(append(First(1), First(2)), First(1));

impl<A: Copy> Copy for First<A>

impl<A: Eq> Eq for First<A>

impl<A> StructuralPartialEq for First<A>