Enum itertools::EitherOrBoth

pub enum EitherOrBoth<A, B> {
    Both(A, B),
    Left(A),
    Right(B),
}

Value that either holds a single A or B, or both.

Variants

Both(A, B)

Both values are present.

Left(A)

Only the left value of type A is present.

Right(B)

Only the right value of type B is present.

Implementations

impl<A, B> EitherOrBoth<A, B>

pub fn has_left(&self) -> bool

If Left, or Both, return true. Otherwise, return false.

pub fn has_right(&self) -> bool

If Right, or Both, return true, otherwise, return false.

pub fn is_left(&self) -> bool

If Left, return true. Otherwise, return false. Exclusive version of has_left.

pub fn is_right(&self) -> bool

If Right, return true. Otherwise, return false. Exclusive version of has_right.

pub fn is_both(&self) -> bool

If Both, return true. Otherwise, return false.

pub fn left(self) -> Option<A>

If Left, or Both, return Some with the left value. Otherwise, return None.

pub fn right(self) -> Option<B>

If Right, or Both, return Some with the right value. Otherwise, return None.

pub fn just_left(self) -> Option<A>

If Left, return Some with the left value. If Right or Both, return None.

Examples

// On the `Left` variant.
let x: EitherOrBoth<_, ()> = Left("bonjour");
assert_eq!(x.just_left(), Some("bonjour"));

// On the `Right` variant.
let x: EitherOrBoth<(), _> = Right("hola");
assert_eq!(x.just_left(), None);

// On the `Both` variant.
let x = Both("bonjour", "hola");
assert_eq!(x.just_left(), None);

pub fn just_right(self) -> Option<B>

If Right, return Some with the right value. If Left or Both, return None.

Examples

// On the `Left` variant.
let x: EitherOrBoth<_, ()> = Left("auf wiedersehen");
assert_eq!(x.just_left(), Some("auf wiedersehen"));

// On the `Right` variant.
let x: EitherOrBoth<(), _> = Right("adios");
assert_eq!(x.just_left(), None);

// On the `Both` variant.
let x = Both("auf wiedersehen", "adios");
assert_eq!(x.just_left(), None);

pub fn both(self) -> Option<(A, B)>

If Both, return Some containing the left and right values. Otherwise, return None.

pub fn into_left(self) -> Awhere B: Into<A>,

If Left or Both, return the left value. Otherwise, convert the right value and return it.

pub fn into_right(self) -> Bwhere A: Into<B>,

If Right or Both, return the right value. Otherwise, convert the left value and return it.

pub fn as_ref(&self) -> EitherOrBoth<&A, &B>

Converts from &EitherOrBoth<A, B> to EitherOrBoth<&A, &B>.

pub fn as_mut(&mut self) -> EitherOrBoth<&mut A, &mut B>

Converts from &mut EitherOrBoth<A, B> to EitherOrBoth<&mut A, &mut B>.

pub fn as_deref(&self) -> EitherOrBoth<&A::Target, &B::Target>where A: Deref, B: Deref,

Converts from &EitherOrBoth<A, B> to EitherOrBoth<&_, &_> using the Deref trait.

pub fn as_deref_mut(&mut self) -> EitherOrBoth<&mut A::Target, &mut B::Target>where A: DerefMut, B: DerefMut,

Converts from &mut EitherOrBoth<A, B> to EitherOrBoth<&mut _, &mut _> using the DerefMut trait.

pub fn flip(self) -> EitherOrBoth<B, A>

Convert EitherOrBoth<A, B> to EitherOrBoth<B, A>.

pub fn map_left<F, M>(self, f: F) -> EitherOrBoth<M, B>where F: FnOnce(A) -> M,

Apply the function f on the value a in Left(a) or Both(a, b) variants. If it is present rewrapping the result in self’s original variant.

pub fn map_right<F, M>(self, f: F) -> EitherOrBoth<A, M>where F: FnOnce(B) -> M,

Apply the function f on the value b in Right(b) or Both(a, b) variants. If it is present rewrapping the result in self’s original variant.

pub fn map_any<F, L, G, R>(self, f: F, g: G) -> EitherOrBoth<L, R>where F: FnOnce(A) -> L, G: FnOnce(B) -> R,

Apply the functions f and g on the value a and b respectively; found in Left(a), Right(b), or Both(a, b) variants. The Result is rewrapped self’s original variant.

pub fn left_and_then<F, L>(self, f: F) -> EitherOrBoth<L, B>where F: FnOnce(A) -> EitherOrBoth<L, B>,

Apply the function f on the value a in Left(a) or Both(a, _) variants if it is present.

pub fn right_and_then<F, R>(self, f: F) -> EitherOrBoth<A, R>where F: FnOnce(B) -> EitherOrBoth<A, R>,

Apply the function f on the value b in Right(b) or Both(_, b) variants if it is present.

pub fn or(self, l: A, r: B) -> (A, B)

Returns a tuple consisting of the l and r in Both(l, r), if present. Otherwise, returns the wrapped value for the present element, and the supplied value for the other. The first (l) argument is used for a missing Left value. The second (r) argument is used for a missing Right value.

Arguments passed to or are eagerly evaluated; if you are passing the result of a function call, it is recommended to use or_else, which is lazily evaluated.

Examples

assert_eq!(EitherOrBoth::Both("tree", 1).or("stone", 5), ("tree", 1));
assert_eq!(EitherOrBoth::Left("tree").or("stone", 5), ("tree", 5));
assert_eq!(EitherOrBoth::Right(1).or("stone", 5), ("stone", 1));

pub fn or_default(self) -> (A, B)where A: Default, B: Default,

Returns a tuple consisting of the l and r in Both(l, r), if present. Otherwise, returns the wrapped value for the present element, and the default for the other.

pub fn or_else<L: FnOnce() -> A, R: FnOnce() -> B>(self, l: L, r: R) -> (A, B)

Returns a tuple consisting of the l and r in Both(l, r), if present. Otherwise, returns the wrapped value for the present element, and computes the missing value with the supplied closure. The first argument (l) is used for a missing Left value. The second argument (r) is used for a missing Right value.

Examples

let k = 10;
assert_eq!(EitherOrBoth::Both("tree", 1).or_else(|| "stone", || 2 * k), ("tree", 1));
assert_eq!(EitherOrBoth::Left("tree").or_else(|| "stone", || 2 * k), ("tree", 20));
assert_eq!(EitherOrBoth::Right(1).or_else(|| "stone", || 2 * k), ("stone", 1));

pub fn left_or_insert(&mut self, val: A) -> &mut A

Returns a mutable reference to the left value. If the left value is not present, it is replaced with val.

pub fn right_or_insert(&mut self, val: B) -> &mut B

Returns a mutable reference to the right value. If the right value is not present, it is replaced with val.

pub fn left_or_insert_with<F>(&mut self, f: F) -> &mut Awhere F: FnOnce() -> A,

If the left value is not present, replace it the value computed by the closure f. Returns a mutable reference to the now-present left value.

pub fn right_or_insert_with<F>(&mut self, f: F) -> &mut Bwhere F: FnOnce() -> B,

If the right value is not present, replace it the value computed by the closure f. Returns a mutable reference to the now-present right value.

pub fn insert_left(&mut self, val: A) -> &mut A

Sets the left value of this instance, and returns a mutable reference to it. Does not affect the right value.

Examples

// Overwriting a pre-existing value.
let mut either: EitherOrBoth<_, ()> = Left(0_u32);
assert_eq!(*either.insert_left(69), 69);

// Inserting a second value.
let mut either = Right("no");
assert_eq!(*either.insert_left("yes"), "yes");
assert_eq!(either, Both("yes", "no"));

pub fn insert_right(&mut self, val: B) -> &mut B

Sets the right value of this instance, and returns a mutable reference to it. Does not affect the left value.

Examples

// Overwriting a pre-existing value.
let mut either: EitherOrBoth<_, ()> = Left(0_u32);
assert_eq!(*either.insert_left(69), 69);

// Inserting a second value.
let mut either = Left("what's");
assert_eq!(*either.insert_right(9 + 10), 21 - 2);
assert_eq!(either, Both("what's", 9+10));

pub fn insert_both(&mut self, left: A, right: B) -> (&mut A, &mut B)

Set self to Both(..), containing the specified left and right values, and returns a mutable reference to those values.

impl<T> EitherOrBoth<T, T>

pub fn reduce<F>(self, f: F) -> Twhere F: FnOnce(T, T) -> T,

Return either value of left, right, or apply a function f to both values if both are present. The input function has to return the same type as both Right and Left carry.

Examples

assert_eq!(EitherOrBoth::Both(3, 7).reduce(u32::max), 7);
assert_eq!(EitherOrBoth::Left(3).reduce(u32::max), 3);
assert_eq!(EitherOrBoth::Right(7).reduce(u32::max), 7);

Trait Implementations

impl<A: Clone, B: Clone> Clone for EitherOrBoth<A, B>

fn clone(&self) -> EitherOrBoth<A, B>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<A: Debug, B: Debug> Debug for EitherOrBoth<A, B>

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

Formats the value using the given formatter.

impl<A: Hash, B: Hash> Hash for EitherOrBoth<A, B>

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, B> Into<Option<Either<A, B>>> for EitherOrBoth<A, B>

fn into(self) -> Option<Either<A, B>>

Converts this type into the (usually inferred) input type.

impl<A: PartialEq, B: PartialEq> PartialEq<EitherOrBoth<A, B>> for EitherOrBoth<A, B>

fn eq(&self, other: &EitherOrBoth<A, B>) -> bool

This method tests for self and other values to be equal, and is used by ==.

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

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

impl<A: Eq, B: Eq> Eq for EitherOrBoth<A, B>

impl<A, B> StructuralEq for EitherOrBoth<A, B>

impl<A, B> StructuralPartialEq for EitherOrBoth<A, B>