Fortune for rematch's current commit: Small blessing − 小吉master
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//! Extensions
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use super::*;
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use std::{
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fmt,
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};
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/// Run an expression on an named value with a result type `Result<T, U>`.
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/// Where `T` and `U` have *the same API surface* for the duration of the provided expression.
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///
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/// # Example
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/// If there is a value `let mut value: Result<T, U>`, where `T: Write` & `U: BufWrite`;
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/// the expression `value.flush()` is valid for both `T` and `U`.
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/// Therefore, it can be simplified to be called as so: `unwrap_either(mut value => value.flush())`.
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///
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/// # Reference capture vs. `move` capture.
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/// Note that by default, the identified value is **moved** *into* the expression.
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/// The type of reference can be controlled by appending `ref`, `mut`, or `ref mut` to the ident.
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///
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/// Identifier capture table:
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/// - **none** ~default~ - Capture by move, value is immutable in expression.
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/// - `mut` - Capture by move, value is mutable in expression.
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/// - `ref` - Capture by ref, value is immutable (`&value`) in expression.
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/// - `ref mut` - Capture by mutable ref, value is mutable (`&mut value`) in expression. (__NOTE__: `value` must be defined as mutable to take a mutable reference of it.)
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///
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/// Essentially the same rules as any `match` branch pattern.
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macro_rules! unwrap_either {
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($res:ident => $($rest:tt)+) => {
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match $res {
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Ok(ref mut $res) => $($rest)+,
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Err(ref mut $res) => $($rest)+,
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}
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};
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(ref mut $res:ident => $($rest:tt)+) => {
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match $res {
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Ok(ref mut $res) => $($rest)+,
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Err(ref mut $res) => $($rest)+,
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}
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};
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(ref $res:ident => $($rest:tt)+) => {
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match $res {
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Ok(ref $res) => $($rest)+,
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Err(ref $res) => $($rest)+,
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}
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};
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(mut $res:ident => $($rest:tt)+) => {
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match $res {
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Ok(mut $res) => $($rest)+,
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Err(mut $res) => $($rest)+,
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}
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};
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}
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pub(crate) use unwrap_either;
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#[derive(Debug, PartialEq, Eq, Hash)]
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#[repr(transparent)]
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pub struct DisjointString<'a, T: ?Sized>([&'a T]);
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macro_rules! disjoint {
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[$($ex:expr),+] => {
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$crate::ext::DisjointString::from_array(& [$($ex),+])
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};
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}
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impl<'a, T: ?Sized> DisjointString<'a, T>
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where T: fmt::Display
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{
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#[inline]
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pub const fn from_array<'o: 'a, const N: usize>(strings: &'o [&'a T; N]) -> &'o Self
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{
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Self::new(strings.as_slice())
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}
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#[inline]
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pub const fn new<'o: 'a>(strings: &'o [&'a T]) -> &'o Self
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{
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// SAFETY: Transparent newtype wrapper over `[&'a T]`
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unsafe {
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std::mem::transmute(strings)
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}
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}
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}
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impl<'a, T: ?Sized> DisjointString<'a, T>
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{
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#[inline]
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pub const fn len(&self) -> usize
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{
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self.0.len()
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}
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#[inline]
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pub fn iter(&self) -> impl Iterator<Item = &T> + ExactSizeIterator + std::iter::FusedIterator + std::iter::DoubleEndedIterator
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{
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self.0.iter().map(|&x| x)
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}
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#[inline]
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pub fn into_iter<'o: 'a>(&'o self) -> impl Iterator<Item = &'a T> + ExactSizeIterator + std::iter::FusedIterator + std::iter::DoubleEndedIterator + 'o
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{
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self.0.into_iter().map(|&x|x)
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}
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}
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impl<'a, T: ?Sized> AsRef<[&'a T]> for DisjointString<'a, T>
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{
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#[inline]
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fn as_ref(&self) -> &[&'a T]
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{
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&self.0
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}
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}
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impl<'a, T: ?Sized> fmt::Display for DisjointString<'a, T>
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where T: fmt::Display
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{
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#[inline]
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result
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{
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for &s in &self.0 {
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s.fmt(f)?;
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}
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Ok(())
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}
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}
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pub(crate) use disjoint;
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