Add BREAK too, and improve the comments

This commit is contained in:
Scott McMurray 2020-09-04 16:28:23 -07:00
parent fac272688e
commit 59e37332b0
3 changed files with 44 additions and 8 deletions

View File

@ -286,7 +286,7 @@ fn node_examined(
prior_status: Option<NodeStatus>,
) -> ControlFlow<Self::BreakVal> {
match prior_status {
Some(NodeStatus::Visited) => ControlFlow::Break(()),
Some(NodeStatus::Visited) => ControlFlow::BREAK,
_ => ControlFlow::CONTINUE,
}
}

View File

@ -2086,10 +2086,10 @@ fn all<F>(&mut self, f: F) -> bool
#[inline]
fn check<T>(mut f: impl FnMut(T) -> bool) -> impl FnMut((), T) -> ControlFlow<(), ()> {
move |(), x| {
if f(x) { ControlFlow::Continue(()) } else { ControlFlow::Break(()) }
if f(x) { ControlFlow::CONTINUE } else { ControlFlow::BREAK }
}
}
self.try_fold((), check(f)) == ControlFlow::Continue(())
self.try_fold((), check(f)) == ControlFlow::CONTINUE
}
/// Tests if any element of the iterator matches a predicate.
@ -2139,11 +2139,11 @@ fn any<F>(&mut self, f: F) -> bool
#[inline]
fn check<T>(mut f: impl FnMut(T) -> bool) -> impl FnMut((), T) -> ControlFlow<(), ()> {
move |(), x| {
if f(x) { ControlFlow::Break(()) } else { ControlFlow::Continue(()) }
if f(x) { ControlFlow::BREAK } else { ControlFlow::CONTINUE }
}
}
self.try_fold((), check(f)) == ControlFlow::Break(())
self.try_fold((), check(f)) == ControlFlow::BREAK
}
/// Searches for an element of an iterator that satisfies a predicate.
@ -2201,7 +2201,7 @@ fn check<T>(
mut predicate: impl FnMut(&T) -> bool,
) -> impl FnMut((), T) -> ControlFlow<(), T> {
move |(), x| {
if predicate(&x) { ControlFlow::Break(x) } else { ControlFlow::Continue(()) }
if predicate(&x) { ControlFlow::Break(x) } else { ControlFlow::CONTINUE }
}
}
@ -2236,7 +2236,7 @@ fn check<T, B>(
) -> impl FnMut((), T) -> ControlFlow<(), B> {
move |(), x| match f(x) {
Some(x) => ControlFlow::Break(x),
None => ControlFlow::Continue(()),
None => ControlFlow::CONTINUE,
}
}
@ -2278,7 +2278,7 @@ fn check<F, T, R>(mut f: F) -> impl FnMut((), T) -> ControlFlow<(), Result<T, R:
R: Try<Ok = bool>,
{
move |(), x| match f(&x).into_result() {
Ok(false) => ControlFlow::Continue(()),
Ok(false) => ControlFlow::CONTINUE,
Ok(true) => ControlFlow::Break(Ok(x)),
Err(x) => ControlFlow::Break(Err(x)),
}

View File

@ -69,6 +69,42 @@ pub fn into_try(self) -> R {
impl<B> ControlFlow<(), B> {
/// It's frequently the case that there's no value needed with `Continue`,
/// so this provides a way to avoid typing `(())`, if you prefer it.
///
/// # Examples
///
/// ```
/// #![feature(control_flow_enum)]
/// use std::ops::ControlFlow;
///
/// let mut partial_sum = 0;
/// let last_used = (1..10).chain(20..25).try_for_each(|x| {
/// partial_sum += x;
/// if partial_sum > 100 { ControlFlow::Break(x) }
/// else { ControlFlow::CONTINUE }
/// });
/// assert_eq!(last_used.break_value(), Some(22));
/// ```
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub const CONTINUE: Self = ControlFlow::Continue(());
}
impl<C> ControlFlow<C, ()> {
/// APIs like `try_for_each` don't need values with `Break`,
/// so this provides a way to avoid typing `(())`, if you prefer it.
///
/// # Examples
///
/// ```
/// #![feature(control_flow_enum)]
/// use std::ops::ControlFlow;
///
/// let mut partial_sum = 0;
/// (1..10).chain(20..25).try_for_each(|x| {
/// if partial_sum > 100 { ControlFlow::BREAK }
/// else { partial_sum += x; ControlFlow::CONTINUE }
/// });
/// assert_eq!(partial_sum, 108);
/// ```
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub const BREAK: Self = ControlFlow::Break(());
}