91 lines
2.4 KiB
Rust
91 lines
2.4 KiB
Rust
// Copyright 2016 Mozilla
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
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// this file except in compliance with the License. You may obtain a copy of the
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// License at http://www.apache.org/licenses/LICENSE-2.0
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// Unless required by applicable law or agreed to in writing, software distributed
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// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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// CONDITIONS OF ANY KIND, either express or implied. See the License for the
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// specific language governing permissions and limitations under the License.
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/// Side-effect chaining on `Result`.
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pub trait ResultEffect<T> {
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/// Invoke `f` if `self` is `Ok`, returning `self`.
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fn when_ok<F: FnOnce()>(self, f: F) -> Self;
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/// Invoke `f` if `self` is `Err`, returning `self`.
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fn when_err<F: FnOnce()>(self, f: F) -> Self;
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}
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impl<T, E> ResultEffect<T> for Result<T, E> {
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fn when_ok<F: FnOnce()>(self, f: F) -> Self {
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if self.is_ok() {
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f();
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}
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self
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}
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fn when_err<F: FnOnce()>(self, f: F) -> Self {
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if self.is_err() {
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f();
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}
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self
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}
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}
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/// Side-effect chaining on `Option`.
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pub trait OptionEffect<T> {
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/// Invoke `f` if `self` is `None`, returning `self`.
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fn when_none<F: FnOnce()>(self, f: F) -> Self;
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/// Invoke `f` if `self` is `Some`, returning `self`.
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fn when_some<F: FnOnce()>(self, f: F) -> Self;
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}
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impl<T> OptionEffect<T> for Option<T> {
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fn when_none<F: FnOnce()>(self, f: F) -> Self {
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if self.is_none() {
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f();
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}
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self
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}
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fn when_some<F: FnOnce()>(self, f: F) -> Self {
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if self.is_some() {
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f();
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}
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self
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}
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}
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#[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
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pub enum Either<L, R> {
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Left(L),
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Right(R),
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}
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// Cribbed from https://github.com/bluss/either/blob/f793721f3fdeb694f009e731b23a2858286bc0d6/src/lib.rs#L219-L259.
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impl<L, R> Either<L, R> {
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pub fn map_left<F, M>(self, f: F) -> Either<M, R>
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where
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F: FnOnce(L) -> M,
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{
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use self::Either::*;
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match self {
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Left(l) => Left(f(l)),
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Right(r) => Right(r),
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}
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}
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pub fn map_right<F, S>(self, f: F) -> Either<L, S>
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where
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F: FnOnce(R) -> S,
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{
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use self::Either::*;
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match self {
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Left(l) => Left(l),
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Right(r) => Right(f(r)),
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}
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}
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}
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