either-1.13.0/.cargo_vcs_info.json0000644000000001360000000000100123760ustar { "git": { "sha1": "e3ec2506f97ab27df3fbb284a3459280cb692c97" }, "path_in_vcs": "" }either-1.13.0/.github/workflows/ci.yml000064400000000000000000000047111046102023000157040ustar 00000000000000on: push: branches: [ main ] pull_request: merge_group: name: CI jobs: ci: runs-on: ubuntu-latest strategy: fail-fast: false matrix: rust: - 1.37.0 # MSRV - stable - beta - nightly features: - "" - "serde" steps: - name: Checkout uses: actions/checkout@v4 - name: Cache the registry uses: actions/cache@v4 if: startsWith(matrix.rust, '1') with: path: ~/.cargo/registry/index key: cargo-${{ matrix.rust }}-git-index - name: Set up Rust uses: dtolnay/rust-toolchain@master with: toolchain: ${{ matrix.rust }} - name: MSRV dependencies if: matrix.rust == '1.37.0' run: | cargo generate-lockfile cargo update -p serde_json --precise 1.0.99 cargo update -p serde --precise 1.0.156 cargo update -p quote --precise 1.0.30 cargo update -p proc-macro2 --precise 1.0.65 - name: Build (no_std) run: cargo build --no-default-features - name: Build run: cargo build --features "${{ matrix.features }}" - name: Test run: cargo test --features "${{ matrix.features }}" - name: Doc run: cargo doc --features "${{ matrix.features }}" clippy: name: Rustfmt and Clippy runs-on: ubuntu-latest steps: - name: Checkout uses: actions/checkout@v4 - name: Set up nightly Rust uses: dtolnay/rust-toolchain@nightly with: components: rustfmt, clippy - name: Rustfmt run: cargo fmt --all -- --check - name: Clippy run: cargo clippy # -- -D warnings # One job that "summarizes" the success state of this pipeline. This can then be added to branch # protection, rather than having to add each job separately. success: name: Success runs-on: ubuntu-latest needs: [ci, clippy] # Github branch protection is exceedingly silly and treats "jobs skipped because a dependency # failed" as success. So we have to do some contortions to ensure the job fails if any of its # dependencies fails. if: always() # make sure this is never "skipped" steps: # Manually check the status of all dependencies. `if: failure()` does not work. - name: check if any dependency failed run: jq --exit-status 'all(.result == "success")' <<< '${{ toJson(needs) }}' either-1.13.0/.gitignore000064400000000000000000000000241046102023000131520ustar 00000000000000/target /Cargo.lock either-1.13.0/Cargo.toml0000644000000024220000000000100103740ustar # THIS FILE IS AUTOMATICALLY GENERATED BY CARGO # # When uploading crates to the registry Cargo will automatically # "normalize" Cargo.toml files for maximal compatibility # with all versions of Cargo and also rewrite `path` dependencies # to registry (e.g., crates.io) dependencies. # # If you are reading this file be aware that the original Cargo.toml # will likely look very different (and much more reasonable). # See Cargo.toml.orig for the original contents. [package] edition = "2018" rust-version = "1.37" name = "either" version = "1.13.0" authors = ["bluss"] description = """ The enum `Either` with variants `Left` and `Right` is a general purpose sum type with two cases. """ documentation = "https://docs.rs/either/1/" readme = "README-crates.io.md" keywords = [ "data-structure", "no_std", ] categories = [ "data-structures", "no-std", ] license = "MIT OR Apache-2.0" repository = "https://github.com/rayon-rs/either" [package.metadata.docs.rs] features = ["serde"] [package.metadata.playground] features = ["serde"] [package.metadata.release] no-dev-version = true tag-name = "{{version}}" [dependencies.serde] version = "1.0" features = ["derive"] optional = true [dev-dependencies.serde_json] version = "1.0.0" [features] default = ["use_std"] use_std = [] either-1.13.0/Cargo.toml.orig000064400000000000000000000014541046102023000140610ustar 00000000000000[package] name = "either" version = "1.13.0" authors = ["bluss"] edition = "2018" rust-version = "1.37" license = "MIT OR Apache-2.0" repository = "https://github.com/rayon-rs/either" documentation = "https://docs.rs/either/1/" readme = "README-crates.io.md" description = """ The enum `Either` with variants `Left` and `Right` is a general purpose sum type with two cases. """ keywords = ["data-structure", "no_std"] categories = ["data-structures", "no-std"] [dependencies] serde = { version = "1.0", optional = true, features = ["derive"] } [features] default = ["use_std"] use_std = [] [dev-dependencies] serde_json = "1.0.0" [package.metadata.release] no-dev-version = true tag-name = "{{version}}" [package.metadata.docs.rs] features = ["serde"] [package.metadata.playground] features = ["serde"] either-1.13.0/LICENSE-APACHE000064400000000000000000000251371046102023000131220ustar 00000000000000 Apache License Version 2.0, January 2004 http://www.apache.org/licenses/ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 1. Definitions. "License" shall mean the terms and conditions for use, reproduction, and distribution as defined by Sections 1 through 9 of this document. "Licensor" shall mean the copyright owner or entity authorized by the copyright owner that is granting the License. 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See the License for the specific language governing permissions and limitations under the License. either-1.13.0/LICENSE-MIT000064400000000000000000000020231046102023000126170ustar 00000000000000Copyright (c) 2015 Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. either-1.13.0/README-crates.io.md000064400000000000000000000006711046102023000143360ustar 00000000000000The enum `Either` with variants `Left` and `Right` is a general purpose sum type with two cases. Either has methods that are similar to Option and Result, and it also implements traits like `Iterator`. Includes macros `try_left!()` and `try_right!()` to use for short-circuiting logic, similar to how the `?` operator is used with `Result`. Note that `Either` is general purpose. For describing success or error, use the regular `Result`. either-1.13.0/README.rst000064400000000000000000000107751046102023000126670ustar 00000000000000 Either ====== The enum ``Either`` with variants ``Left`` and ``Right`` and trait implementations including Iterator, Read, Write. Either has methods that are similar to Option and Result. Includes convenience macros ``try_left!()`` and ``try_right!()`` to use for short-circuiting logic. Please read the `API documentation here`__ __ https://docs.rs/either/ |build_status|_ |crates|_ .. |build_status| image:: https://github.com/rayon-rs/either/workflows/CI/badge.svg?branch=main .. _build_status: https://github.com/rayon-rs/either/actions .. |crates| image:: https://img.shields.io/crates/v/either.svg .. _crates: https://crates.io/crates/either How to use with cargo:: [dependencies] either = "1.12" Recent Changes -------------- - 1.13.0 - Add new methods ``.cloned()`` and ``.copied()``, by @ColonelThirtyTwo (#107) - 1.12.0 - **MSRV**: ``either`` now requires Rust 1.37 or later. - Specialize ``nth_back`` for ``Either`` and ``IterEither``, by @cuviper (#106) - 1.11.0 - Add new trait ``IntoEither`` that is useful to convert to ``Either`` in method chains, by @SFM61319 (#101) - 1.10.0 - Add new methods ``.factor_iter()``, ``.factor_iter_mut()``, and ``.factor_into_iter()`` that return ``Either`` items, plus ``.iter()`` and ``.iter_mut()`` to convert to direct referene iterators; by @aj-bagwell and @cuviper (#91) - 1.9.0 - Add new methods ``.map_either()`` and ``.map_either_with()``, by @nasadorian (#82) - 1.8.1 - Clarified that the multiple licenses are combined with OR. - 1.8.0 - **MSRV**: ``either`` now requires Rust 1.36 or later. - Add new methods ``.as_pin_ref()`` and ``.as_pin_mut()`` to project a pinned ``Either`` as inner ``Pin`` variants, by @cuviper (#77) - Implement the ``Future`` trait, by @cuviper (#77) - Specialize more methods of the ``io`` traits, by @Kixunil and @cuviper (#75) - 1.7.0 - **MSRV**: ``either`` now requires Rust 1.31 or later. - Export the macro ``for_both!``, by @thomaseizinger (#58) - Implement the ``io::Seek`` trait, by @Kerollmops (#60) - Add new method ``.either_into()`` for ``Into`` conversion, by @TonalidadeHidrica (#63) - Add new methods ``.factor_ok()``, ``.factor_err()``, and ``.factor_none()``, by @zachs18 (#67) - Specialize ``source`` in the ``Error`` implementation, by @thomaseizinger (#69) - Specialize more iterator methods and implement the ``FusedIterator`` trait, by @Ten0 (#66) and @cuviper (#71) - Specialize ``Clone::clone_from``, by @cuviper (#72) - 1.6.1 - Add new methods ``.expect_left()``, ``.unwrap_left()``, and equivalents on the right, by @spenserblack (#51) - 1.6.0 - Add new modules ``serde_untagged`` and ``serde_untagged_optional`` to customize how ``Either`` fields are serialized in other types, by @MikailBag (#49) - 1.5.3 - Add new method ``.map()`` for ``Either`` by @nvzqz (#40). - 1.5.2 - Add new methods ``.left_or()``, ``.left_or_default()``, ``.left_or_else()``, and equivalents on the right, by @DCjanus (#36) - 1.5.1 - Add ``AsRef`` and ``AsMut`` implementations for common unsized types: ``str``, ``[T]``, ``CStr``, ``OsStr``, and ``Path``, by @mexus (#29) - 1.5.0 - Add new methods ``.factor_first()``, ``.factor_second()`` and ``.into_inner()`` by @mathstuf (#19) - 1.4.0 - Add inherent method ``.into_iter()`` by @cuviper (#12) - 1.3.0 - Add opt-in serde support by @hcpl - 1.2.0 - Add method ``.either_with()`` by @Twey (#13) - 1.1.0 - Add methods ``left_and_then``, ``right_and_then`` by @rampantmonkey - Include license files in the repository and released crate - 1.0.3 - Add crate categories - 1.0.2 - Forward more ``Iterator`` methods - Implement ``Extend`` for ``Either`` if ``L, R`` do. - 1.0.1 - Fix ``Iterator`` impl for ``Either`` to forward ``.fold()``. - 1.0.0 - Add default crate feature ``use_std`` so that you can opt out of linking to std. - 0.1.7 - Add methods ``.map_left()``, ``.map_right()`` and ``.either()``. - Add more documentation - 0.1.3 - Implement Display, Error - 0.1.2 - Add macros ``try_left!`` and ``try_right!``. - 0.1.1 - Implement Deref, DerefMut - 0.1.0 - Initial release - Support Iterator, Read, Write License ------- Dual-licensed to be compatible with the Rust project. Licensed under the Apache License, Version 2.0 https://www.apache.org/licenses/LICENSE-2.0 or the MIT license https://opensource.org/licenses/MIT, at your option. This file may not be copied, modified, or distributed except according to those terms. either-1.13.0/src/into_either.rs000064400000000000000000000040501046102023000146330ustar 00000000000000//! The trait [`IntoEither`] provides methods for converting a type `Self`, whose //! size is constant and known at compile-time, into an [`Either`] variant. use super::{Either, Left, Right}; /// Provides methods for converting a type `Self` into either a [`Left`] or [`Right`] /// variant of [`Either`](Either). /// /// The [`into_either`](IntoEither::into_either) method takes a [`bool`] to determine /// whether to convert to [`Left`] or [`Right`]. /// /// The [`into_either_with`](IntoEither::into_either_with) method takes a /// [predicate function](FnOnce) to determine whether to convert to [`Left`] or [`Right`]. pub trait IntoEither: Sized { /// Converts `self` into a [`Left`] variant of [`Either`](Either) /// if `into_left` is `true`. /// Converts `self` into a [`Right`] variant of [`Either`](Either) /// otherwise. /// /// # Examples /// /// ``` /// use either::{IntoEither, Left, Right}; /// /// let x = 0; /// assert_eq!(x.into_either(true), Left(x)); /// assert_eq!(x.into_either(false), Right(x)); /// ``` fn into_either(self, into_left: bool) -> Either { if into_left { Left(self) } else { Right(self) } } /// Converts `self` into a [`Left`] variant of [`Either`](Either) /// if `into_left(&self)` returns `true`. /// Converts `self` into a [`Right`] variant of [`Either`](Either) /// otherwise. /// /// # Examples /// /// ``` /// use either::{IntoEither, Left, Right}; /// /// fn is_even(x: &u8) -> bool { /// x % 2 == 0 /// } /// /// let x = 0; /// assert_eq!(x.into_either_with(is_even), Left(x)); /// assert_eq!(x.into_either_with(|x| !is_even(x)), Right(x)); /// ``` fn into_either_with(self, into_left: F) -> Either where F: FnOnce(&Self) -> bool, { let into_left = into_left(&self); self.into_either(into_left) } } impl IntoEither for T {} either-1.13.0/src/iterator.rs000064400000000000000000000166141046102023000141640ustar 00000000000000use super::{for_both, Either, Left, Right}; use core::iter; macro_rules! wrap_either { ($value:expr => $( $tail:tt )*) => { match $value { Left(inner) => inner.map(Left) $($tail)*, Right(inner) => inner.map(Right) $($tail)*, } }; } /// Iterator that maps left or right iterators to corresponding `Either`-wrapped items. /// /// This struct is created by the [`Either::factor_into_iter`], /// [`factor_iter`][Either::factor_iter], /// and [`factor_iter_mut`][Either::factor_iter_mut] methods. #[derive(Clone, Debug)] pub struct IterEither { inner: Either, } impl IterEither { pub(crate) fn new(inner: Either) -> Self { IterEither { inner } } } impl Extend for Either where L: Extend, R: Extend, { fn extend(&mut self, iter: T) where T: IntoIterator, { for_both!(*self, ref mut inner => inner.extend(iter)) } } /// `Either` is an iterator if both `L` and `R` are iterators. impl Iterator for Either where L: Iterator, R: Iterator, { type Item = L::Item; fn next(&mut self) -> Option { for_both!(*self, ref mut inner => inner.next()) } fn size_hint(&self) -> (usize, Option) { for_both!(*self, ref inner => inner.size_hint()) } fn fold(self, init: Acc, f: G) -> Acc where G: FnMut(Acc, Self::Item) -> Acc, { for_both!(self, inner => inner.fold(init, f)) } fn for_each(self, f: F) where F: FnMut(Self::Item), { for_both!(self, inner => inner.for_each(f)) } fn count(self) -> usize { for_both!(self, inner => inner.count()) } fn last(self) -> Option { for_both!(self, inner => inner.last()) } fn nth(&mut self, n: usize) -> Option { for_both!(*self, ref mut inner => inner.nth(n)) } fn collect(self) -> B where B: iter::FromIterator, { for_both!(self, inner => inner.collect()) } fn partition(self, f: F) -> (B, B) where B: Default + Extend, F: FnMut(&Self::Item) -> bool, { for_both!(self, inner => inner.partition(f)) } fn all(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool, { for_both!(*self, ref mut inner => inner.all(f)) } fn any(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool, { for_both!(*self, ref mut inner => inner.any(f)) } fn find

(&mut self, predicate: P) -> Option where P: FnMut(&Self::Item) -> bool, { for_both!(*self, ref mut inner => inner.find(predicate)) } fn find_map(&mut self, f: F) -> Option where F: FnMut(Self::Item) -> Option, { for_both!(*self, ref mut inner => inner.find_map(f)) } fn position

(&mut self, predicate: P) -> Option where P: FnMut(Self::Item) -> bool, { for_both!(*self, ref mut inner => inner.position(predicate)) } } impl DoubleEndedIterator for Either where L: DoubleEndedIterator, R: DoubleEndedIterator, { fn next_back(&mut self) -> Option { for_both!(*self, ref mut inner => inner.next_back()) } fn nth_back(&mut self, n: usize) -> Option { for_both!(*self, ref mut inner => inner.nth_back(n)) } fn rfold(self, init: Acc, f: G) -> Acc where G: FnMut(Acc, Self::Item) -> Acc, { for_both!(self, inner => inner.rfold(init, f)) } fn rfind

(&mut self, predicate: P) -> Option where P: FnMut(&Self::Item) -> bool, { for_both!(*self, ref mut inner => inner.rfind(predicate)) } } impl ExactSizeIterator for Either where L: ExactSizeIterator, R: ExactSizeIterator, { fn len(&self) -> usize { for_both!(*self, ref inner => inner.len()) } } impl iter::FusedIterator for Either where L: iter::FusedIterator, R: iter::FusedIterator, { } impl Iterator for IterEither where L: Iterator, R: Iterator, { type Item = Either; fn next(&mut self) -> Option { Some(map_either!(self.inner, ref mut inner => inner.next()?)) } fn size_hint(&self) -> (usize, Option) { for_both!(self.inner, ref inner => inner.size_hint()) } fn fold(self, init: Acc, f: G) -> Acc where G: FnMut(Acc, Self::Item) -> Acc, { wrap_either!(self.inner => .fold(init, f)) } fn for_each(self, f: F) where F: FnMut(Self::Item), { wrap_either!(self.inner => .for_each(f)) } fn count(self) -> usize { for_both!(self.inner, inner => inner.count()) } fn last(self) -> Option { Some(map_either!(self.inner, inner => inner.last()?)) } fn nth(&mut self, n: usize) -> Option { Some(map_either!(self.inner, ref mut inner => inner.nth(n)?)) } fn collect(self) -> B where B: iter::FromIterator, { wrap_either!(self.inner => .collect()) } fn partition(self, f: F) -> (B, B) where B: Default + Extend, F: FnMut(&Self::Item) -> bool, { wrap_either!(self.inner => .partition(f)) } fn all(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool, { wrap_either!(&mut self.inner => .all(f)) } fn any(&mut self, f: F) -> bool where F: FnMut(Self::Item) -> bool, { wrap_either!(&mut self.inner => .any(f)) } fn find

(&mut self, predicate: P) -> Option where P: FnMut(&Self::Item) -> bool, { wrap_either!(&mut self.inner => .find(predicate)) } fn find_map(&mut self, f: F) -> Option where F: FnMut(Self::Item) -> Option, { wrap_either!(&mut self.inner => .find_map(f)) } fn position

(&mut self, predicate: P) -> Option where P: FnMut(Self::Item) -> bool, { wrap_either!(&mut self.inner => .position(predicate)) } } impl DoubleEndedIterator for IterEither where L: DoubleEndedIterator, R: DoubleEndedIterator, { fn next_back(&mut self) -> Option { Some(map_either!(self.inner, ref mut inner => inner.next_back()?)) } fn nth_back(&mut self, n: usize) -> Option { Some(map_either!(self.inner, ref mut inner => inner.nth_back(n)?)) } fn rfold(self, init: Acc, f: G) -> Acc where G: FnMut(Acc, Self::Item) -> Acc, { wrap_either!(self.inner => .rfold(init, f)) } fn rfind

(&mut self, predicate: P) -> Option where P: FnMut(&Self::Item) -> bool, { wrap_either!(&mut self.inner => .rfind(predicate)) } } impl ExactSizeIterator for IterEither where L: ExactSizeIterator, R: ExactSizeIterator, { fn len(&self) -> usize { for_both!(self.inner, ref inner => inner.len()) } } impl iter::FusedIterator for IterEither where L: iter::FusedIterator, R: iter::FusedIterator, { } either-1.13.0/src/lib.rs000064400000000000000000001270731046102023000131030ustar 00000000000000//! The enum [`Either`] with variants `Left` and `Right` is a general purpose //! sum type with two cases. //! //! [`Either`]: enum.Either.html //! //! **Crate features:** //! //! * `"use_std"` //! Enabled by default. Disable to make the library `#![no_std]`. //! //! * `"serde"` //! Disabled by default. Enable to `#[derive(Serialize, Deserialize)]` for `Either` //! #![doc(html_root_url = "https://docs.rs/either/1/")] #![no_std] #[cfg(any(test, feature = "use_std"))] extern crate std; #[cfg(feature = "serde")] pub mod serde_untagged; #[cfg(feature = "serde")] pub mod serde_untagged_optional; use core::convert::{AsMut, AsRef}; use core::fmt; use core::future::Future; use core::ops::Deref; use core::ops::DerefMut; use core::pin::Pin; #[cfg(any(test, feature = "use_std"))] use std::error::Error; #[cfg(any(test, feature = "use_std"))] use std::io::{self, BufRead, Read, Seek, SeekFrom, Write}; pub use crate::Either::{Left, Right}; /// The enum `Either` with variants `Left` and `Right` is a general purpose /// sum type with two cases. /// /// The `Either` type is symmetric and treats its variants the same way, without /// preference. /// (For representing success or error, use the regular `Result` enum instead.) #[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))] #[derive(Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] pub enum Either { /// A value of type `L`. Left(L), /// A value of type `R`. Right(R), } /// Evaluate the provided expression for both [`Either::Left`] and [`Either::Right`]. /// /// This macro is useful in cases where both sides of [`Either`] can be interacted with /// in the same way even though the don't share the same type. /// /// Syntax: `either::for_both!(` *expression* `,` *pattern* `=>` *expression* `)` /// /// # Example /// /// ``` /// use either::Either; /// /// fn length(owned_or_borrowed: Either) -> usize { /// either::for_both!(owned_or_borrowed, s => s.len()) /// } /// /// fn main() { /// let borrowed = Either::Right("Hello world!"); /// let owned = Either::Left("Hello world!".to_owned()); /// /// assert_eq!(length(borrowed), 12); /// assert_eq!(length(owned), 12); /// } /// ``` #[macro_export] macro_rules! for_both { ($value:expr, $pattern:pat => $result:expr) => { match $value { $crate::Either::Left($pattern) => $result, $crate::Either::Right($pattern) => $result, } }; } /// Macro for unwrapping the left side of an [`Either`], which fails early /// with the opposite side. Can only be used in functions that return /// `Either` because of the early return of `Right` that it provides. /// /// See also [`try_right!`] for its dual, which applies the same just to the /// right side. /// /// # Example /// /// ``` /// use either::{Either, Left, Right}; /// /// fn twice(wrapper: Either) -> Either { /// let value = either::try_left!(wrapper); /// Left(value * 2) /// } /// /// fn main() { /// assert_eq!(twice(Left(2)), Left(4)); /// assert_eq!(twice(Right("ups")), Right("ups")); /// } /// ``` #[macro_export] macro_rules! try_left { ($expr:expr) => { match $expr { $crate::Left(val) => val, $crate::Right(err) => return $crate::Right(::core::convert::From::from(err)), } }; } /// Dual to [`try_left!`], see its documentation for more information. #[macro_export] macro_rules! try_right { ($expr:expr) => { match $expr { $crate::Left(err) => return $crate::Left(::core::convert::From::from(err)), $crate::Right(val) => val, } }; } macro_rules! map_either { ($value:expr, $pattern:pat => $result:expr) => { match $value { Left($pattern) => Left($result), Right($pattern) => Right($result), } }; } mod iterator; pub use self::iterator::IterEither; mod into_either; pub use self::into_either::IntoEither; impl Clone for Either { fn clone(&self) -> Self { match self { Left(inner) => Left(inner.clone()), Right(inner) => Right(inner.clone()), } } fn clone_from(&mut self, source: &Self) { match (self, source) { (Left(dest), Left(source)) => dest.clone_from(source), (Right(dest), Right(source)) => dest.clone_from(source), (dest, source) => *dest = source.clone(), } } } impl Either { /// Return true if the value is the `Left` variant. /// /// ``` /// use either::*; /// /// let values = [Left(1), Right("the right value")]; /// assert_eq!(values[0].is_left(), true); /// assert_eq!(values[1].is_left(), false); /// ``` pub fn is_left(&self) -> bool { match *self { Left(_) => true, Right(_) => false, } } /// Return true if the value is the `Right` variant. /// /// ``` /// use either::*; /// /// let values = [Left(1), Right("the right value")]; /// assert_eq!(values[0].is_right(), false); /// assert_eq!(values[1].is_right(), true); /// ``` pub fn is_right(&self) -> bool { !self.is_left() } /// Convert the left side of `Either` to an `Option`. /// /// ``` /// use either::*; /// /// let left: Either<_, ()> = Left("some value"); /// assert_eq!(left.left(), Some("some value")); /// /// let right: Either<(), _> = Right(321); /// assert_eq!(right.left(), None); /// ``` pub fn left(self) -> Option { match self { Left(l) => Some(l), Right(_) => None, } } /// Convert the right side of `Either` to an `Option`. /// /// ``` /// use either::*; /// /// let left: Either<_, ()> = Left("some value"); /// assert_eq!(left.right(), None); /// /// let right: Either<(), _> = Right(321); /// assert_eq!(right.right(), Some(321)); /// ``` pub fn right(self) -> Option { match self { Left(_) => None, Right(r) => Some(r), } } /// Convert `&Either` to `Either<&L, &R>`. /// /// ``` /// use either::*; /// /// let left: Either<_, ()> = Left("some value"); /// assert_eq!(left.as_ref(), Left(&"some value")); /// /// let right: Either<(), _> = Right("some value"); /// assert_eq!(right.as_ref(), Right(&"some value")); /// ``` pub fn as_ref(&self) -> Either<&L, &R> { match *self { Left(ref inner) => Left(inner), Right(ref inner) => Right(inner), } } /// Convert `&mut Either` to `Either<&mut L, &mut R>`. /// /// ``` /// use either::*; /// /// fn mutate_left(value: &mut Either) { /// if let Some(l) = value.as_mut().left() { /// *l = 999; /// } /// } /// /// let mut left = Left(123); /// let mut right = Right(123); /// mutate_left(&mut left); /// mutate_left(&mut right); /// assert_eq!(left, Left(999)); /// assert_eq!(right, Right(123)); /// ``` pub fn as_mut(&mut self) -> Either<&mut L, &mut R> { match *self { Left(ref mut inner) => Left(inner), Right(ref mut inner) => Right(inner), } } /// Convert `Pin<&Either>` to `Either, Pin<&R>>`, /// pinned projections of the inner variants. pub fn as_pin_ref(self: Pin<&Self>) -> Either, Pin<&R>> { // SAFETY: We can use `new_unchecked` because the `inner` parts are // guaranteed to be pinned, as they come from `self` which is pinned. unsafe { match *Pin::get_ref(self) { Left(ref inner) => Left(Pin::new_unchecked(inner)), Right(ref inner) => Right(Pin::new_unchecked(inner)), } } } /// Convert `Pin<&mut Either>` to `Either, Pin<&mut R>>`, /// pinned projections of the inner variants. pub fn as_pin_mut(self: Pin<&mut Self>) -> Either, Pin<&mut R>> { // SAFETY: `get_unchecked_mut` is fine because we don't move anything. // We can use `new_unchecked` because the `inner` parts are guaranteed // to be pinned, as they come from `self` which is pinned, and we never // offer an unpinned `&mut L` or `&mut R` through `Pin<&mut Self>`. We // also don't have an implementation of `Drop`, nor manual `Unpin`. unsafe { match *Pin::get_unchecked_mut(self) { Left(ref mut inner) => Left(Pin::new_unchecked(inner)), Right(ref mut inner) => Right(Pin::new_unchecked(inner)), } } } /// Convert `Either` to `Either`. /// /// ``` /// use either::*; /// /// let left: Either<_, ()> = Left(123); /// assert_eq!(left.flip(), Right(123)); /// /// let right: Either<(), _> = Right("some value"); /// assert_eq!(right.flip(), Left("some value")); /// ``` pub fn flip(self) -> Either { match self { Left(l) => Right(l), Right(r) => Left(r), } } /// Apply the function `f` on the value in the `Left` variant if it is present rewrapping the /// result in `Left`. /// /// ``` /// use either::*; /// /// let left: Either<_, u32> = Left(123); /// assert_eq!(left.map_left(|x| x * 2), Left(246)); /// /// let right: Either = Right(123); /// assert_eq!(right.map_left(|x| x * 2), Right(123)); /// ``` pub fn map_left(self, f: F) -> Either where F: FnOnce(L) -> M, { match self { Left(l) => Left(f(l)), Right(r) => Right(r), } } /// Apply the function `f` on the value in the `Right` variant if it is present rewrapping the /// result in `Right`. /// /// ``` /// use either::*; /// /// let left: Either<_, u32> = Left(123); /// assert_eq!(left.map_right(|x| x * 2), Left(123)); /// /// let right: Either = Right(123); /// assert_eq!(right.map_right(|x| x * 2), Right(246)); /// ``` pub fn map_right(self, f: F) -> Either where F: FnOnce(R) -> S, { match self { Left(l) => Left(l), Right(r) => Right(f(r)), } } /// Apply the functions `f` and `g` to the `Left` and `Right` variants /// respectively. This is equivalent to /// [bimap](https://hackage.haskell.org/package/bifunctors-5/docs/Data-Bifunctor.html) /// in functional programming. /// /// ``` /// use either::*; /// /// let f = |s: String| s.len(); /// let g = |u: u8| u.to_string(); /// /// let left: Either = Left("loopy".into()); /// assert_eq!(left.map_either(f, g), Left(5)); /// /// let right: Either = Right(42); /// assert_eq!(right.map_either(f, g), Right("42".into())); /// ``` pub fn map_either(self, f: F, g: G) -> Either where F: FnOnce(L) -> M, G: FnOnce(R) -> S, { match self { Left(l) => Left(f(l)), Right(r) => Right(g(r)), } } /// Similar to [`map_either`][Self::map_either], with an added context `ctx` accessible to /// both functions. /// /// ``` /// use either::*; /// /// let mut sum = 0; /// /// // Both closures want to update the same value, so pass it as context. /// let mut f = |sum: &mut usize, s: String| { *sum += s.len(); s.to_uppercase() }; /// let mut g = |sum: &mut usize, u: usize| { *sum += u; u.to_string() }; /// /// let left: Either = Left("loopy".into()); /// assert_eq!(left.map_either_with(&mut sum, &mut f, &mut g), Left("LOOPY".into())); /// /// let right: Either = Right(42); /// assert_eq!(right.map_either_with(&mut sum, &mut f, &mut g), Right("42".into())); /// /// assert_eq!(sum, 47); /// ``` pub fn map_either_with(self, ctx: Ctx, f: F, g: G) -> Either where F: FnOnce(Ctx, L) -> M, G: FnOnce(Ctx, R) -> S, { match self { Left(l) => Left(f(ctx, l)), Right(r) => Right(g(ctx, r)), } } /// Apply one of two functions depending on contents, unifying their result. If the value is /// `Left(L)` then the first function `f` is applied; if it is `Right(R)` then the second /// function `g` is applied. /// /// ``` /// use either::*; /// /// fn square(n: u32) -> i32 { (n * n) as i32 } /// fn negate(n: i32) -> i32 { -n } /// /// let left: Either = Left(4); /// assert_eq!(left.either(square, negate), 16); /// /// let right: Either = Right(-4); /// assert_eq!(right.either(square, negate), 4); /// ``` pub fn either(self, f: F, g: G) -> T where F: FnOnce(L) -> T, G: FnOnce(R) -> T, { match self { Left(l) => f(l), Right(r) => g(r), } } /// Like [`either`][Self::either], but provide some context to whichever of the /// functions ends up being called. /// /// ``` /// // In this example, the context is a mutable reference /// use either::*; /// /// let mut result = Vec::new(); /// /// let values = vec![Left(2), Right(2.7)]; /// /// for value in values { /// value.either_with(&mut result, /// |ctx, integer| ctx.push(integer), /// |ctx, real| ctx.push(f64::round(real) as i32)); /// } /// /// assert_eq!(result, vec![2, 3]); /// ``` pub fn either_with(self, ctx: Ctx, f: F, g: G) -> T where F: FnOnce(Ctx, L) -> T, G: FnOnce(Ctx, R) -> T, { match self { Left(l) => f(ctx, l), Right(r) => g(ctx, r), } } /// Apply the function `f` on the value in the `Left` variant if it is present. /// /// ``` /// use either::*; /// /// let left: Either<_, u32> = Left(123); /// assert_eq!(left.left_and_then::<_,()>(|x| Right(x * 2)), Right(246)); /// /// let right: Either = Right(123); /// assert_eq!(right.left_and_then(|x| Right::<(), _>(x * 2)), Right(123)); /// ``` pub fn left_and_then(self, f: F) -> Either where F: FnOnce(L) -> Either, { match self { Left(l) => f(l), Right(r) => Right(r), } } /// Apply the function `f` on the value in the `Right` variant if it is present. /// /// ``` /// use either::*; /// /// let left: Either<_, u32> = Left(123); /// assert_eq!(left.right_and_then(|x| Right(x * 2)), Left(123)); /// /// let right: Either = Right(123); /// assert_eq!(right.right_and_then(|x| Right(x * 2)), Right(246)); /// ``` pub fn right_and_then(self, f: F) -> Either where F: FnOnce(R) -> Either, { match self { Left(l) => Left(l), Right(r) => f(r), } } /// Convert the inner value to an iterator. /// /// This requires the `Left` and `Right` iterators to have the same item type. /// See [`factor_into_iter`][Either::factor_into_iter] to iterate different types. /// /// ``` /// use either::*; /// /// let left: Either<_, Vec> = Left(vec![1, 2, 3, 4, 5]); /// let mut right: Either, _> = Right(vec![]); /// right.extend(left.into_iter()); /// assert_eq!(right, Right(vec![1, 2, 3, 4, 5])); /// ``` #[allow(clippy::should_implement_trait)] pub fn into_iter(self) -> Either where L: IntoIterator, R: IntoIterator, { map_either!(self, inner => inner.into_iter()) } /// Borrow the inner value as an iterator. /// /// This requires the `Left` and `Right` iterators to have the same item type. /// See [`factor_iter`][Either::factor_iter] to iterate different types. /// /// ``` /// use either::*; /// /// let left: Either<_, &[u32]> = Left(vec![2, 3]); /// let mut right: Either, _> = Right(&[4, 5][..]); /// let mut all = vec![1]; /// all.extend(left.iter()); /// all.extend(right.iter()); /// assert_eq!(all, vec![1, 2, 3, 4, 5]); /// ``` pub fn iter(&self) -> Either<<&L as IntoIterator>::IntoIter, <&R as IntoIterator>::IntoIter> where for<'a> &'a L: IntoIterator, for<'a> &'a R: IntoIterator::Item>, { map_either!(self, inner => inner.into_iter()) } /// Mutably borrow the inner value as an iterator. /// /// This requires the `Left` and `Right` iterators to have the same item type. /// See [`factor_iter_mut`][Either::factor_iter_mut] to iterate different types. /// /// ``` /// use either::*; /// /// let mut left: Either<_, &mut [u32]> = Left(vec![2, 3]); /// for l in left.iter_mut() { /// *l *= *l /// } /// assert_eq!(left, Left(vec![4, 9])); /// /// let mut inner = [4, 5]; /// let mut right: Either, _> = Right(&mut inner[..]); /// for r in right.iter_mut() { /// *r *= *r /// } /// assert_eq!(inner, [16, 25]); /// ``` pub fn iter_mut( &mut self, ) -> Either<<&mut L as IntoIterator>::IntoIter, <&mut R as IntoIterator>::IntoIter> where for<'a> &'a mut L: IntoIterator, for<'a> &'a mut R: IntoIterator::Item>, { map_either!(self, inner => inner.into_iter()) } /// Converts an `Either` of `Iterator`s to be an `Iterator` of `Either`s /// /// Unlike [`into_iter`][Either::into_iter], this does not require the /// `Left` and `Right` iterators to have the same item type. /// /// ``` /// use either::*; /// let left: Either<_, Vec> = Left(&["hello"]); /// assert_eq!(left.factor_into_iter().next(), Some(Left(&"hello"))); /// let right: Either<&[&str], _> = Right(vec![0, 1]); /// assert_eq!(right.factor_into_iter().collect::>(), vec![Right(0), Right(1)]); /// /// ``` // TODO(MSRV): doc(alias) was stabilized in Rust 1.48 // #[doc(alias = "transpose")] pub fn factor_into_iter(self) -> IterEither where L: IntoIterator, R: IntoIterator, { IterEither::new(map_either!(self, inner => inner.into_iter())) } /// Borrows an `Either` of `Iterator`s to be an `Iterator` of `Either`s /// /// Unlike [`iter`][Either::iter], this does not require the /// `Left` and `Right` iterators to have the same item type. /// /// ``` /// use either::*; /// let left: Either<_, Vec> = Left(["hello"]); /// assert_eq!(left.factor_iter().next(), Some(Left(&"hello"))); /// let right: Either<[&str; 2], _> = Right(vec![0, 1]); /// assert_eq!(right.factor_iter().collect::>(), vec![Right(&0), Right(&1)]); /// /// ``` pub fn factor_iter( &self, ) -> IterEither<<&L as IntoIterator>::IntoIter, <&R as IntoIterator>::IntoIter> where for<'a> &'a L: IntoIterator, for<'a> &'a R: IntoIterator, { IterEither::new(map_either!(self, inner => inner.into_iter())) } /// Mutably borrows an `Either` of `Iterator`s to be an `Iterator` of `Either`s /// /// Unlike [`iter_mut`][Either::iter_mut], this does not require the /// `Left` and `Right` iterators to have the same item type. /// /// ``` /// use either::*; /// let mut left: Either<_, Vec> = Left(["hello"]); /// left.factor_iter_mut().for_each(|x| *x.unwrap_left() = "goodbye"); /// assert_eq!(left, Left(["goodbye"])); /// let mut right: Either<[&str; 2], _> = Right(vec![0, 1, 2]); /// right.factor_iter_mut().for_each(|x| if let Right(r) = x { *r = -*r; }); /// assert_eq!(right, Right(vec![0, -1, -2])); /// /// ``` pub fn factor_iter_mut( &mut self, ) -> IterEither<<&mut L as IntoIterator>::IntoIter, <&mut R as IntoIterator>::IntoIter> where for<'a> &'a mut L: IntoIterator, for<'a> &'a mut R: IntoIterator, { IterEither::new(map_either!(self, inner => inner.into_iter())) } /// Return left value or given value /// /// Arguments passed to `left_or` are eagerly evaluated; if you are passing /// the result of a function call, it is recommended to use /// [`left_or_else`][Self::left_or_else], which is lazily evaluated. /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either<&str, &str> = Left("left"); /// assert_eq!(left.left_or("foo"), "left"); /// /// let right: Either<&str, &str> = Right("right"); /// assert_eq!(right.left_or("left"), "left"); /// ``` pub fn left_or(self, other: L) -> L { match self { Either::Left(l) => l, Either::Right(_) => other, } } /// Return left or a default /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either = Left("left".to_string()); /// assert_eq!(left.left_or_default(), "left"); /// /// let right: Either = Right(42); /// assert_eq!(right.left_or_default(), String::default()); /// ``` pub fn left_or_default(self) -> L where L: Default, { match self { Either::Left(l) => l, Either::Right(_) => L::default(), } } /// Returns left value or computes it from a closure /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either = Left("3".to_string()); /// assert_eq!(left.left_or_else(|_| unreachable!()), "3"); /// /// let right: Either = Right(3); /// assert_eq!(right.left_or_else(|x| x.to_string()), "3"); /// ``` pub fn left_or_else(self, f: F) -> L where F: FnOnce(R) -> L, { match self { Either::Left(l) => l, Either::Right(r) => f(r), } } /// Return right value or given value /// /// Arguments passed to `right_or` are eagerly evaluated; if you are passing /// the result of a function call, it is recommended to use /// [`right_or_else`][Self::right_or_else], which is lazily evaluated. /// /// # Examples /// /// ``` /// # use either::*; /// let right: Either<&str, &str> = Right("right"); /// assert_eq!(right.right_or("foo"), "right"); /// /// let left: Either<&str, &str> = Left("left"); /// assert_eq!(left.right_or("right"), "right"); /// ``` pub fn right_or(self, other: R) -> R { match self { Either::Left(_) => other, Either::Right(r) => r, } } /// Return right or a default /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either = Left("left".to_string()); /// assert_eq!(left.right_or_default(), u32::default()); /// /// let right: Either = Right(42); /// assert_eq!(right.right_or_default(), 42); /// ``` pub fn right_or_default(self) -> R where R: Default, { match self { Either::Left(_) => R::default(), Either::Right(r) => r, } } /// Returns right value or computes it from a closure /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either = Left("3".to_string()); /// assert_eq!(left.right_or_else(|x| x.parse().unwrap()), 3); /// /// let right: Either = Right(3); /// assert_eq!(right.right_or_else(|_| unreachable!()), 3); /// ``` pub fn right_or_else(self, f: F) -> R where F: FnOnce(L) -> R, { match self { Either::Left(l) => f(l), Either::Right(r) => r, } } /// Returns the left value /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either<_, ()> = Left(3); /// assert_eq!(left.unwrap_left(), 3); /// ``` /// /// # Panics /// /// When `Either` is a `Right` value /// /// ```should_panic /// # use either::*; /// let right: Either<(), _> = Right(3); /// right.unwrap_left(); /// ``` pub fn unwrap_left(self) -> L where R: core::fmt::Debug, { match self { Either::Left(l) => l, Either::Right(r) => { panic!("called `Either::unwrap_left()` on a `Right` value: {:?}", r) } } } /// Returns the right value /// /// # Examples /// /// ``` /// # use either::*; /// let right: Either<(), _> = Right(3); /// assert_eq!(right.unwrap_right(), 3); /// ``` /// /// # Panics /// /// When `Either` is a `Left` value /// /// ```should_panic /// # use either::*; /// let left: Either<_, ()> = Left(3); /// left.unwrap_right(); /// ``` pub fn unwrap_right(self) -> R where L: core::fmt::Debug, { match self { Either::Right(r) => r, Either::Left(l) => panic!("called `Either::unwrap_right()` on a `Left` value: {:?}", l), } } /// Returns the left value /// /// # Examples /// /// ``` /// # use either::*; /// let left: Either<_, ()> = Left(3); /// assert_eq!(left.expect_left("value was Right"), 3); /// ``` /// /// # Panics /// /// When `Either` is a `Right` value /// /// ```should_panic /// # use either::*; /// let right: Either<(), _> = Right(3); /// right.expect_left("value was Right"); /// ``` pub fn expect_left(self, msg: &str) -> L where R: core::fmt::Debug, { match self { Either::Left(l) => l, Either::Right(r) => panic!("{}: {:?}", msg, r), } } /// Returns the right value /// /// # Examples /// /// ``` /// # use either::*; /// let right: Either<(), _> = Right(3); /// assert_eq!(right.expect_right("value was Left"), 3); /// ``` /// /// # Panics /// /// When `Either` is a `Left` value /// /// ```should_panic /// # use either::*; /// let left: Either<_, ()> = Left(3); /// left.expect_right("value was Right"); /// ``` pub fn expect_right(self, msg: &str) -> R where L: core::fmt::Debug, { match self { Either::Right(r) => r, Either::Left(l) => panic!("{}: {:?}", msg, l), } } /// Convert the contained value into `T` /// /// # Examples /// /// ``` /// # use either::*; /// // Both u16 and u32 can be converted to u64. /// let left: Either = Left(3u16); /// assert_eq!(left.either_into::(), 3u64); /// let right: Either = Right(7u32); /// assert_eq!(right.either_into::(), 7u64); /// ``` pub fn either_into(self) -> T where L: Into, R: Into, { match self { Either::Left(l) => l.into(), Either::Right(r) => r.into(), } } } impl Either, Option> { /// Factors out `None` from an `Either` of [`Option`]. /// /// ``` /// use either::*; /// let left: Either<_, Option> = Left(Some(vec![0])); /// assert_eq!(left.factor_none(), Some(Left(vec![0]))); /// /// let right: Either>, _> = Right(Some(String::new())); /// assert_eq!(right.factor_none(), Some(Right(String::new()))); /// ``` // TODO(MSRV): doc(alias) was stabilized in Rust 1.48 // #[doc(alias = "transpose")] pub fn factor_none(self) -> Option> { match self { Left(l) => l.map(Either::Left), Right(r) => r.map(Either::Right), } } } impl Either, Result> { /// Factors out a homogenous type from an `Either` of [`Result`]. /// /// Here, the homogeneous type is the `Err` type of the [`Result`]. /// /// ``` /// use either::*; /// let left: Either<_, Result> = Left(Ok(vec![0])); /// assert_eq!(left.factor_err(), Ok(Left(vec![0]))); /// /// let right: Either, u32>, _> = Right(Ok(String::new())); /// assert_eq!(right.factor_err(), Ok(Right(String::new()))); /// ``` // TODO(MSRV): doc(alias) was stabilized in Rust 1.48 // #[doc(alias = "transpose")] pub fn factor_err(self) -> Result, E> { match self { Left(l) => l.map(Either::Left), Right(r) => r.map(Either::Right), } } } impl Either, Result> { /// Factors out a homogenous type from an `Either` of [`Result`]. /// /// Here, the homogeneous type is the `Ok` type of the [`Result`]. /// /// ``` /// use either::*; /// let left: Either<_, Result> = Left(Err(vec![0])); /// assert_eq!(left.factor_ok(), Err(Left(vec![0]))); /// /// let right: Either>, _> = Right(Err(String::new())); /// assert_eq!(right.factor_ok(), Err(Right(String::new()))); /// ``` // TODO(MSRV): doc(alias) was stabilized in Rust 1.48 // #[doc(alias = "transpose")] pub fn factor_ok(self) -> Result> { match self { Left(l) => l.map_err(Either::Left), Right(r) => r.map_err(Either::Right), } } } impl Either<(T, L), (T, R)> { /// Factor out a homogeneous type from an either of pairs. /// /// Here, the homogeneous type is the first element of the pairs. /// /// ``` /// use either::*; /// let left: Either<_, (u32, String)> = Left((123, vec![0])); /// assert_eq!(left.factor_first().0, 123); /// /// let right: Either<(u32, Vec), _> = Right((123, String::new())); /// assert_eq!(right.factor_first().0, 123); /// ``` pub fn factor_first(self) -> (T, Either) { match self { Left((t, l)) => (t, Left(l)), Right((t, r)) => (t, Right(r)), } } } impl Either<(L, T), (R, T)> { /// Factor out a homogeneous type from an either of pairs. /// /// Here, the homogeneous type is the second element of the pairs. /// /// ``` /// use either::*; /// let left: Either<_, (String, u32)> = Left((vec![0], 123)); /// assert_eq!(left.factor_second().1, 123); /// /// let right: Either<(Vec, u32), _> = Right((String::new(), 123)); /// assert_eq!(right.factor_second().1, 123); /// ``` pub fn factor_second(self) -> (Either, T) { match self { Left((l, t)) => (Left(l), t), Right((r, t)) => (Right(r), t), } } } impl Either { /// Extract the value of an either over two equivalent types. /// /// ``` /// use either::*; /// /// let left: Either<_, u32> = Left(123); /// assert_eq!(left.into_inner(), 123); /// /// let right: Either = Right(123); /// assert_eq!(right.into_inner(), 123); /// ``` pub fn into_inner(self) -> T { for_both!(self, inner => inner) } /// Map `f` over the contained value and return the result in the /// corresponding variant. /// /// ``` /// use either::*; /// /// let value: Either<_, i32> = Right(42); /// /// let other = value.map(|x| x * 2); /// assert_eq!(other, Right(84)); /// ``` pub fn map(self, f: F) -> Either where F: FnOnce(T) -> M, { match self { Left(l) => Left(f(l)), Right(r) => Right(f(r)), } } } impl Either<&L, &R> { /// Maps an `Either<&L, &R>` to an `Either` by cloning the contents of /// either branch. pub fn cloned(self) -> Either where L: Clone, R: Clone, { match self { Self::Left(l) => Either::Left(l.clone()), Self::Right(r) => Either::Right(r.clone()), } } /// Maps an `Either<&L, &R>` to an `Either` by copying the contents of /// either branch. pub fn copied(self) -> Either where L: Copy, R: Copy, { match self { Self::Left(l) => Either::Left(*l), Self::Right(r) => Either::Right(*r), } } } impl Either<&mut L, &mut R> { /// Maps an `Either<&mut L, &mut R>` to an `Either` by cloning the contents of /// either branch. pub fn cloned(self) -> Either where L: Clone, R: Clone, { match self { Self::Left(l) => Either::Left(l.clone()), Self::Right(r) => Either::Right(r.clone()), } } /// Maps an `Either<&mut L, &mut R>` to an `Either` by copying the contents of /// either branch. pub fn copied(self) -> Either where L: Copy, R: Copy, { match self { Self::Left(l) => Either::Left(*l), Self::Right(r) => Either::Right(*r), } } } /// Convert from `Result` to `Either` with `Ok => Right` and `Err => Left`. impl From> for Either { fn from(r: Result) -> Self { match r { Err(e) => Left(e), Ok(o) => Right(o), } } } /// Convert from `Either` to `Result` with `Right => Ok` and `Left => Err`. #[allow(clippy::from_over_into)] // From requires RFC 2451, Rust 1.41 impl Into> for Either { fn into(self) -> Result { match self { Left(l) => Err(l), Right(r) => Ok(r), } } } /// `Either` is a future if both `L` and `R` are futures. impl Future for Either where L: Future, R: Future, { type Output = L::Output; fn poll( self: Pin<&mut Self>, cx: &mut core::task::Context<'_>, ) -> core::task::Poll { for_both!(self.as_pin_mut(), inner => inner.poll(cx)) } } #[cfg(any(test, feature = "use_std"))] /// `Either` implements `Read` if both `L` and `R` do. /// /// Requires crate feature `"use_std"` impl Read for Either where L: Read, R: Read, { fn read(&mut self, buf: &mut [u8]) -> io::Result { for_both!(*self, ref mut inner => inner.read(buf)) } fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> { for_both!(*self, ref mut inner => inner.read_exact(buf)) } fn read_to_end(&mut self, buf: &mut std::vec::Vec) -> io::Result { for_both!(*self, ref mut inner => inner.read_to_end(buf)) } fn read_to_string(&mut self, buf: &mut std::string::String) -> io::Result { for_both!(*self, ref mut inner => inner.read_to_string(buf)) } } #[cfg(any(test, feature = "use_std"))] /// `Either` implements `Seek` if both `L` and `R` do. /// /// Requires crate feature `"use_std"` impl Seek for Either where L: Seek, R: Seek, { fn seek(&mut self, pos: SeekFrom) -> io::Result { for_both!(*self, ref mut inner => inner.seek(pos)) } } #[cfg(any(test, feature = "use_std"))] /// Requires crate feature `"use_std"` impl BufRead for Either where L: BufRead, R: BufRead, { fn fill_buf(&mut self) -> io::Result<&[u8]> { for_both!(*self, ref mut inner => inner.fill_buf()) } fn consume(&mut self, amt: usize) { for_both!(*self, ref mut inner => inner.consume(amt)) } fn read_until(&mut self, byte: u8, buf: &mut std::vec::Vec) -> io::Result { for_both!(*self, ref mut inner => inner.read_until(byte, buf)) } fn read_line(&mut self, buf: &mut std::string::String) -> io::Result { for_both!(*self, ref mut inner => inner.read_line(buf)) } } #[cfg(any(test, feature = "use_std"))] /// `Either` implements `Write` if both `L` and `R` do. /// /// Requires crate feature `"use_std"` impl Write for Either where L: Write, R: Write, { fn write(&mut self, buf: &[u8]) -> io::Result { for_both!(*self, ref mut inner => inner.write(buf)) } fn write_all(&mut self, buf: &[u8]) -> io::Result<()> { for_both!(*self, ref mut inner => inner.write_all(buf)) } fn write_fmt(&mut self, fmt: fmt::Arguments<'_>) -> io::Result<()> { for_both!(*self, ref mut inner => inner.write_fmt(fmt)) } fn flush(&mut self) -> io::Result<()> { for_both!(*self, ref mut inner => inner.flush()) } } impl AsRef for Either where L: AsRef, R: AsRef, { fn as_ref(&self) -> &Target { for_both!(*self, ref inner => inner.as_ref()) } } macro_rules! impl_specific_ref_and_mut { ($t:ty, $($attr:meta),* ) => { $(#[$attr])* impl AsRef<$t> for Either where L: AsRef<$t>, R: AsRef<$t> { fn as_ref(&self) -> &$t { for_both!(*self, ref inner => inner.as_ref()) } } $(#[$attr])* impl AsMut<$t> for Either where L: AsMut<$t>, R: AsMut<$t> { fn as_mut(&mut self) -> &mut $t { for_both!(*self, ref mut inner => inner.as_mut()) } } }; } impl_specific_ref_and_mut!(str,); impl_specific_ref_and_mut!( ::std::path::Path, cfg(feature = "use_std"), doc = "Requires crate feature `use_std`." ); impl_specific_ref_and_mut!( ::std::ffi::OsStr, cfg(feature = "use_std"), doc = "Requires crate feature `use_std`." ); impl_specific_ref_and_mut!( ::std::ffi::CStr, cfg(feature = "use_std"), doc = "Requires crate feature `use_std`." ); impl AsRef<[Target]> for Either where L: AsRef<[Target]>, R: AsRef<[Target]>, { fn as_ref(&self) -> &[Target] { for_both!(*self, ref inner => inner.as_ref()) } } impl AsMut for Either where L: AsMut, R: AsMut, { fn as_mut(&mut self) -> &mut Target { for_both!(*self, ref mut inner => inner.as_mut()) } } impl AsMut<[Target]> for Either where L: AsMut<[Target]>, R: AsMut<[Target]>, { fn as_mut(&mut self) -> &mut [Target] { for_both!(*self, ref mut inner => inner.as_mut()) } } impl Deref for Either where L: Deref, R: Deref, { type Target = L::Target; fn deref(&self) -> &Self::Target { for_both!(*self, ref inner => &**inner) } } impl DerefMut for Either where L: DerefMut, R: DerefMut, { fn deref_mut(&mut self) -> &mut Self::Target { for_both!(*self, ref mut inner => &mut *inner) } } #[cfg(any(test, feature = "use_std"))] /// `Either` implements `Error` if *both* `L` and `R` implement it. /// /// Requires crate feature `"use_std"` impl Error for Either where L: Error, R: Error, { fn source(&self) -> Option<&(dyn Error + 'static)> { for_both!(*self, ref inner => inner.source()) } #[allow(deprecated)] fn description(&self) -> &str { for_both!(*self, ref inner => inner.description()) } #[allow(deprecated)] fn cause(&self) -> Option<&dyn Error> { for_both!(*self, ref inner => inner.cause()) } } impl fmt::Display for Either where L: fmt::Display, R: fmt::Display, { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { for_both!(*self, ref inner => inner.fmt(f)) } } #[test] fn basic() { let mut e = Left(2); let r = Right(2); assert_eq!(e, Left(2)); e = r; assert_eq!(e, Right(2)); assert_eq!(e.left(), None); assert_eq!(e.right(), Some(2)); assert_eq!(e.as_ref().right(), Some(&2)); assert_eq!(e.as_mut().right(), Some(&mut 2)); } #[test] fn macros() { use std::string::String; fn a() -> Either { let x: u32 = try_left!(Right(1337u32)); Left(x * 2) } assert_eq!(a(), Right(1337)); fn b() -> Either { Right(try_right!(Left("foo bar"))) } assert_eq!(b(), Left(String::from("foo bar"))); } #[test] fn deref() { use std::string::String; fn is_str(_: &str) {} let value: Either = Left(String::from("test")); is_str(&*value); } #[test] fn iter() { let x = 3; let mut iter = match x { 3 => Left(0..10), _ => Right(17..), }; assert_eq!(iter.next(), Some(0)); assert_eq!(iter.count(), 9); } #[test] fn seek() { use std::io; let use_empty = false; let mut mockdata = [0x00; 256]; for i in 0..256 { mockdata[i] = i as u8; } let mut reader = if use_empty { // Empty didn't impl Seek until Rust 1.51 Left(io::Cursor::new([])) } else { Right(io::Cursor::new(&mockdata[..])) }; let mut buf = [0u8; 16]; assert_eq!(reader.read(&mut buf).unwrap(), buf.len()); assert_eq!(buf, mockdata[..buf.len()]); // the first read should advance the cursor and return the next 16 bytes thus the `ne` assert_eq!(reader.read(&mut buf).unwrap(), buf.len()); assert_ne!(buf, mockdata[..buf.len()]); // if the seek operation fails it should read 16..31 instead of 0..15 reader.seek(io::SeekFrom::Start(0)).unwrap(); assert_eq!(reader.read(&mut buf).unwrap(), buf.len()); assert_eq!(buf, mockdata[..buf.len()]); } #[test] fn read_write() { use std::io; let use_stdio = false; let mockdata = [0xff; 256]; let mut reader = if use_stdio { Left(io::stdin()) } else { Right(&mockdata[..]) }; let mut buf = [0u8; 16]; assert_eq!(reader.read(&mut buf).unwrap(), buf.len()); assert_eq!(&buf, &mockdata[..buf.len()]); let mut mockbuf = [0u8; 256]; let mut writer = if use_stdio { Left(io::stdout()) } else { Right(&mut mockbuf[..]) }; let buf = [1u8; 16]; assert_eq!(writer.write(&buf).unwrap(), buf.len()); } #[test] fn error() { let invalid_utf8 = b"\xff"; #[allow(invalid_from_utf8)] let res = if let Err(error) = ::std::str::from_utf8(invalid_utf8) { Err(Left(error)) } else if let Err(error) = "x".parse::() { Err(Right(error)) } else { Ok(()) }; assert!(res.is_err()); #[allow(deprecated)] res.unwrap_err().description(); // make sure this can be called } /// A helper macro to check if AsRef and AsMut are implemented for a given type. macro_rules! check_t { ($t:ty) => {{ fn check_ref>() {} fn propagate_ref, T2: AsRef<$t>>() { check_ref::>() } fn check_mut>() {} fn propagate_mut, T2: AsMut<$t>>() { check_mut::>() } }}; } // This "unused" method is here to ensure that compilation doesn't fail on given types. fn _unsized_ref_propagation() { check_t!(str); fn check_array_ref, Item>() {} fn check_array_mut, Item>() {} fn propagate_array_ref, T2: AsRef<[Item]>, Item>() { check_array_ref::, _>() } fn propagate_array_mut, T2: AsMut<[Item]>, Item>() { check_array_mut::, _>() } } // This "unused" method is here to ensure that compilation doesn't fail on given types. #[cfg(feature = "use_std")] fn _unsized_std_propagation() { check_t!(::std::path::Path); check_t!(::std::ffi::OsStr); check_t!(::std::ffi::CStr); } either-1.13.0/src/serde_untagged.rs000064400000000000000000000037541046102023000153140ustar 00000000000000//! Untagged serialization/deserialization support for Either. //! //! `Either` uses default, externally-tagged representation. //! However, sometimes it is useful to support several alternative types. //! For example, we may have a field which is generally Map //! but in typical cases Vec would suffice, too. //! //! ```rust //! # fn main() -> Result<(), Box> { //! use either::Either; //! use std::collections::HashMap; //! //! #[derive(serde::Serialize, serde::Deserialize, Debug)] //! #[serde(transparent)] //! struct IntOrString { //! #[serde(with = "either::serde_untagged")] //! inner: Either, HashMap> //! }; //! //! // serialization //! let data = IntOrString { //! inner: Either::Left(vec!["Hello".to_string()]) //! }; //! // notice: no tags are emitted. //! assert_eq!(serde_json::to_string(&data)?, r#"["Hello"]"#); //! //! // deserialization //! let data: IntOrString = serde_json::from_str( //! r#"{"a": 0, "b": 14}"# //! )?; //! println!("found {:?}", data); //! # Ok(()) //! # } //! ``` use serde::{Deserialize, Deserializer, Serialize, Serializer}; #[derive(serde::Serialize, serde::Deserialize)] #[serde(untagged)] enum Either { Left(L), Right(R), } pub fn serialize(this: &super::Either, serializer: S) -> Result where S: Serializer, L: Serialize, R: Serialize, { let untagged = match this { super::Either::Left(left) => Either::Left(left), super::Either::Right(right) => Either::Right(right), }; untagged.serialize(serializer) } pub fn deserialize<'de, L, R, D>(deserializer: D) -> Result, D::Error> where D: Deserializer<'de>, L: Deserialize<'de>, R: Deserialize<'de>, { match Either::deserialize(deserializer) { Ok(Either::Left(left)) => Ok(super::Either::Left(left)), Ok(Either::Right(right)) => Ok(super::Either::Right(right)), Err(error) => Err(error), } } either-1.13.0/src/serde_untagged_optional.rs000064400000000000000000000041741046102023000172160ustar 00000000000000//! Untagged serialization/deserialization support for Option>. //! //! `Either` uses default, externally-tagged representation. //! However, sometimes it is useful to support several alternative types. //! For example, we may have a field which is generally Map //! but in typical cases Vec would suffice, too. //! //! ```rust //! # fn main() -> Result<(), Box> { //! use either::Either; //! use std::collections::HashMap; //! //! #[derive(serde::Serialize, serde::Deserialize, Debug)] //! #[serde(transparent)] //! struct IntOrString { //! #[serde(with = "either::serde_untagged_optional")] //! inner: Option, HashMap>> //! }; //! //! // serialization //! let data = IntOrString { //! inner: Some(Either::Left(vec!["Hello".to_string()])) //! }; //! // notice: no tags are emitted. //! assert_eq!(serde_json::to_string(&data)?, r#"["Hello"]"#); //! //! // deserialization //! let data: IntOrString = serde_json::from_str( //! r#"{"a": 0, "b": 14}"# //! )?; //! println!("found {:?}", data); //! # Ok(()) //! # } //! ``` use serde::{Deserialize, Deserializer, Serialize, Serializer}; #[derive(Serialize, Deserialize)] #[serde(untagged)] enum Either { Left(L), Right(R), } pub fn serialize( this: &Option>, serializer: S, ) -> Result where S: Serializer, L: Serialize, R: Serialize, { let untagged = match this { Some(super::Either::Left(left)) => Some(Either::Left(left)), Some(super::Either::Right(right)) => Some(Either::Right(right)), None => None, }; untagged.serialize(serializer) } pub fn deserialize<'de, L, R, D>(deserializer: D) -> Result>, D::Error> where D: Deserializer<'de>, L: Deserialize<'de>, R: Deserialize<'de>, { match Option::deserialize(deserializer) { Ok(Some(Either::Left(left))) => Ok(Some(super::Either::Left(left))), Ok(Some(Either::Right(right))) => Ok(Some(super::Either::Right(right))), Ok(None) => Ok(None), Err(error) => Err(error), } }