Enum ContextCell 

pub enum ContextCell<C> {
    Present(C),
    Missing,
}

A wrapper around context that allows it to be taken and returned without requiring all interactions to unwrap (as with Option<C>).

Variants

Present(C)

A context available for use.

Missing

The context has been taken elsewhere.

Implementations

impl<C> Cell<C>

pub const fn new(context: C) -> Self

Create a new slot containing context.

pub fn take(&mut self) -> C

Remove the context from the slot, panicking if it is missing.

pub fn restore(&mut self, context: C)

Return a context to the slot, panicking if one is already present.

pub fn as_present(&self) -> &C

Returns a reference to the context.

Panics

Panics if the context is missing.

pub fn as_present_mut(&mut self) -> &mut C

Returns a mutable reference to the context.

Panics

Panics if the context is missing.

pub fn into_present(self) -> C

Consume the slot, returning the context.

Panics

Panics if the context is missing.

Trait Implementations

impl<C> AsMut<C> for Cell<C>

fn as_mut(&mut self) -> &mut C

Converts this type into a mutable reference of the (usually inferred) input type.

impl<C> AsRef<C> for Cell<C>

fn as_ref(&self) -> &C

Converts this type into a shared reference of the (usually inferred) input type.

impl<C: Debug> Debug for Cell<C>

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

Formats the value using the given formatter.

impl<C> Deref for Cell<C>

type Target = C

The resulting type after dereferencing.

fn deref(&self) -> &C

Dereferences the value.

impl<C> DerefMut for Cell<C>

fn deref_mut(&mut self) -> &mut C

Mutably dereferences the value.