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use crate::ops::Try;
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum ControlFlow<B, C = ()> {
Continue(C),
Break(B),
}
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
impl<B, C> Try for ControlFlow<B, C> {
type Ok = C;
type Error = B;
#[inline]
fn into_result(self) -> Result<Self::Ok, Self::Error> {
match self {
ControlFlow::Continue(y) => Ok(y),
ControlFlow::Break(x) => Err(x),
}
}
#[inline]
fn from_error(v: Self::Error) -> Self {
ControlFlow::Break(v)
}
#[inline]
fn from_ok(v: Self::Ok) -> Self {
ControlFlow::Continue(v)
}
}
impl<B, C> ControlFlow<B, C> {
#[inline]
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub fn is_break(&self) -> bool {
matches!(*self, ControlFlow::Break(_))
}
#[inline]
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub fn is_continue(&self) -> bool {
matches!(*self, ControlFlow::Continue(_))
}
#[inline]
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub fn break_value(self) -> Option<B> {
match self {
ControlFlow::Continue(..) => None,
ControlFlow::Break(x) => Some(x),
}
}
#[inline]
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub fn map_break<T, F>(self, f: F) -> ControlFlow<T, C>
where
F: FnOnce(B) -> T,
{
match self {
ControlFlow::Continue(x) => ControlFlow::Continue(x),
ControlFlow::Break(x) => ControlFlow::Break(f(x)),
}
}
}
impl<R: Try> ControlFlow<R, R::Ok> {
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
#[inline]
pub fn from_try(r: R) -> Self {
match Try::into_result(r) {
Ok(v) => ControlFlow::Continue(v),
Err(v) => ControlFlow::Break(Try::from_error(v)),
}
}
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
#[inline]
pub fn into_try(self) -> R {
match self {
ControlFlow::Continue(v) => Try::from_ok(v),
ControlFlow::Break(v) => v,
}
}
}
impl<B> ControlFlow<B, ()> {
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub const CONTINUE: Self = ControlFlow::Continue(());
}
impl<C> ControlFlow<(), C> {
#[unstable(feature = "control_flow_enum", reason = "new API", issue = "75744")]
pub const BREAK: Self = ControlFlow::Break(());
}