Enum core::ops::ControlFlow

pub enum ControlFlow<C, B> {
    Continue(C),
    Break(B),
}

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Used to make try_fold closures more like normal loops

Variants

Continue(C)

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Continue in the loop, using the given value for the next iteration

Break(B)

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Exit the loop, yielding the given value

Implementations

impl<C, B> ControlFlow<C, B>

pub fn break_value(self) -> Option<B>

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Converts the ControlFlow into an Option which is Some if the ControlFlow was Break and None otherwise.

impl<R: Try> ControlFlow<R::Ok, R>

pub fn from_try(r: R) -> Self

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Create a ControlFlow from any type implementing Try.

pub fn into_try(self) -> R

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

Convert a ControlFlow into any type implementing Try;

impl<B> ControlFlow<(), B>

pub const CONTINUE: Self

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

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));

impl<C> ControlFlow<C, ()>

pub const BREAK: Self

🔬 This is a nightly-only experimental API. (control_flow_enum #75744)

new API

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);

Trait Implementations

impl<C: Clone, B: Clone> Clone for ControlFlow<C, B>

fn clone(&self) -> ControlFlow<C, B>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<C: Copy, B: Copy> Copy for ControlFlow<C, B>

impl<C: Debug, B: Debug> Debug for ControlFlow<C, B>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<C: PartialEq, B: PartialEq> PartialEq<ControlFlow<C, B>> for ControlFlow<C, B>

fn eq(&self, other: &ControlFlow<C, B>) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &ControlFlow<C, B>) -> bool

This method tests for !=.

impl<C, B> StructuralPartialEq for ControlFlow<C, B>

impl<C, B> Try for ControlFlow<C, B>

type Ok = C

🔬 This is a nightly-only experimental API. (try_trait #42327)

The type of this value when viewed as successful.

type Error = B

🔬 This is a nightly-only experimental API. (try_trait #42327)

The type of this value when viewed as failed.

fn into_result(self) -> Result<Self::Ok, Self::Error>

🔬 This is a nightly-only experimental API. (try_trait #42327)

Applies the "?" operator. A return of Ok(t) means that the execution should continue normally, and the result of ? is the value t. A return of Err(e) means that execution should branch to the innermost enclosing catch, or return from the function.

fn from_error(v: Self::Error) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

Wrap an error value to construct the composite result. For example, Result::Err(x) and Result::from_error(x) are equivalent.

fn from_ok(v: Self::Ok) -> Self

🔬 This is a nightly-only experimental API. (try_trait #42327)

Wrap an OK value to construct the composite result. For example, Result::Ok(x) and Result::from_ok(x) are equivalent.