206 lines
6.0 KiB
Rust
206 lines
6.0 KiB
Rust
use crate::EitherOrBoth::*;
|
|
|
|
use either::Either;
|
|
|
|
/// Value that either holds a single A or B, or both.
|
|
#[derive(Clone, PartialEq, Eq, Hash, Debug)]
|
|
pub enum EitherOrBoth<A, B> {
|
|
/// Both values are present.
|
|
Both(A, B),
|
|
/// Only the left value of type `A` is present.
|
|
Left(A),
|
|
/// Only the right value of type `B` is present.
|
|
Right(B),
|
|
}
|
|
|
|
impl<A, B> EitherOrBoth<A, B> {
|
|
/// If `Left`, or `Both`, return true, otherwise, return false.
|
|
pub fn has_left(&self) -> bool {
|
|
self.as_ref().left().is_some()
|
|
}
|
|
|
|
/// If `Right`, or `Both`, return true, otherwise, return false.
|
|
pub fn has_right(&self) -> bool {
|
|
self.as_ref().right().is_some()
|
|
}
|
|
|
|
/// If Left, return true otherwise, return false.
|
|
/// Exclusive version of [`has_left`](EitherOrBoth::has_left).
|
|
pub fn is_left(&self) -> bool {
|
|
match *self {
|
|
Left(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// If Right, return true otherwise, return false.
|
|
/// Exclusive version of [`has_right`](EitherOrBoth::has_right).
|
|
pub fn is_right(&self) -> bool {
|
|
match *self {
|
|
Right(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// If Right, return true otherwise, return false.
|
|
/// Equivalent to `self.as_ref().both().is_some()`.
|
|
pub fn is_both(&self) -> bool {
|
|
self.as_ref().both().is_some()
|
|
}
|
|
|
|
/// If `Left`, or `Both`, return `Some` with the left value, otherwise, return `None`.
|
|
pub fn left(self) -> Option<A> {
|
|
match self {
|
|
Left(left) | Both(left, _) => Some(left),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// If `Right`, or `Both`, return `Some` with the right value, otherwise, return `None`.
|
|
pub fn right(self) -> Option<B> {
|
|
match self {
|
|
Right(right) | Both(_, right) => Some(right),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// If Both, return `Some` tuple containing left and right.
|
|
pub fn both(self) -> Option<(A, B)> {
|
|
match self {
|
|
Both(a, b) => Some((a, b)),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// Converts from `&EitherOrBoth<A, B>` to `EitherOrBoth<&A, &B>`.
|
|
pub fn as_ref(&self) -> EitherOrBoth<&A, &B> {
|
|
match *self {
|
|
Left(ref left) => Left(left),
|
|
Right(ref right) => Right(right),
|
|
Both(ref left, ref right) => Both(left, right),
|
|
}
|
|
}
|
|
|
|
/// Converts from `&mut EitherOrBoth<A, B>` to `EitherOrBoth<&mut A, &mut B>`.
|
|
pub fn as_mut(&mut self) -> EitherOrBoth<&mut A, &mut B> {
|
|
match *self {
|
|
Left(ref mut left) => Left(left),
|
|
Right(ref mut right) => Right(right),
|
|
Both(ref mut left, ref mut right) => Both(left, right),
|
|
}
|
|
}
|
|
|
|
/// Convert `EitherOrBoth<A, B>` to `EitherOrBoth<B, A>`.
|
|
pub fn flip(self) -> EitherOrBoth<B, A> {
|
|
match self {
|
|
Left(a) => Right(a),
|
|
Right(b) => Left(b),
|
|
Both(a, b) => Both(b, a),
|
|
}
|
|
}
|
|
|
|
/// 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_left<F, M>(self, f: F) -> EitherOrBoth<M, B>
|
|
where
|
|
F: FnOnce(A) -> M,
|
|
{
|
|
match self {
|
|
Both(a, b) => Both(f(a), b),
|
|
Left(a) => Left(f(a)),
|
|
Right(b) => Right(b),
|
|
}
|
|
}
|
|
|
|
/// 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_right<F, M>(self, f: F) -> EitherOrBoth<A, M>
|
|
where
|
|
F: FnOnce(B) -> M,
|
|
{
|
|
match self {
|
|
Left(a) => Left(a),
|
|
Right(b) => Right(f(b)),
|
|
Both(a, b) => Both(a, f(b)),
|
|
}
|
|
}
|
|
|
|
/// 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 map_any<F, L, G, R>(self, f: F, g: G) -> EitherOrBoth<L, R>
|
|
where
|
|
F: FnOnce(A) -> L,
|
|
G: FnOnce(B) -> R,
|
|
{
|
|
match self {
|
|
Left(a) => Left(f(a)),
|
|
Right(b) => Right(g(b)),
|
|
Both(a, b) => Both(f(a), g(b)),
|
|
}
|
|
}
|
|
|
|
/// Apply the function `f` on the value `a` in `Left(a)` or `Both(a, _)` variants if it is
|
|
/// present.
|
|
pub fn left_and_then<F, L>(self, f: F) -> EitherOrBoth<L, B>
|
|
where
|
|
F: FnOnce(A) -> EitherOrBoth<L, B>,
|
|
{
|
|
match self {
|
|
Left(a) | Both(a, _) => f(a),
|
|
Right(b) => Right(b),
|
|
}
|
|
}
|
|
|
|
/// Apply the function `f` on the value `b`
|
|
/// in `Right(b)` or `Both(_, b)` 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>,
|
|
{
|
|
match self {
|
|
Left(a) => Left(a),
|
|
Right(b) | Both(_, b) => f(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 [`default`](Default::default)
|
|
/// for the other.
|
|
pub fn or_default(self) -> (A, B)
|
|
where
|
|
A: Default,
|
|
B: Default,
|
|
{
|
|
match self {
|
|
EitherOrBoth::Left(l) => (l, B::default()),
|
|
EitherOrBoth::Right(r) => (A::default(), r),
|
|
EitherOrBoth::Both(l, r) => (l, r),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<T> EitherOrBoth<T, T> {
|
|
/// Return either value of left, right, or the product of `f` applied where `Both` are present.
|
|
pub fn reduce<F>(self, f: F) -> T
|
|
where
|
|
F: FnOnce(T, T) -> T,
|
|
{
|
|
match self {
|
|
Left(a) => a,
|
|
Right(b) => b,
|
|
Both(a, b) => f(a, b),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<A, B> Into<Option<Either<A, B>>> for EitherOrBoth<A, B> {
|
|
fn into(self) -> Option<Either<A, B>> {
|
|
match self {
|
|
EitherOrBoth::Left(l) => Some(Either::Left(l)),
|
|
EitherOrBoth::Right(r) => Some(Either::Right(r)),
|
|
_ => None,
|
|
}
|
|
}
|
|
}
|