Enum PullStep 

pub enum PullStep<Item, Meta, CanPend: Toggle, CanEnd: Toggle> {
    Ready(Item, Meta),
    Pending(CanPend),
    Ended(CanEnd),
}

The result of polling a Pull.

PullStep represents the three possible outcomes when pulling from a stream:

• Ready(item, meta): An item is available along with associated metadata.
• Pending(can_pend): No item is available yet, but more may come (async).
• Ended(can_end): The stream has terminated and will produce no more items.

The CanPend and CanEnd type parameters use Toggle to statically encode which variants are possible. When a variant is impossible (e.g., CanPend = No), its payload type becomes No, making it a compile error to construct.

Variants

Ready(Item, Meta)

An item is ready with associated metadata.

Pending(CanPend)

The pull is not ready yet (only possible when CanPend = Yes).

Ended(CanEnd)

The pull has ended (only possible when CanEnd = Yes).

Implementations

impl<Item, Meta, CanPend: Toggle, CanEnd: Toggle> PullStep<Item, Meta, CanPend, CanEnd>

pub fn ended() -> Self

Creates a new PullStep::Ended, or panics if CanEnd = No.

pub fn pending() -> Self

Creates a new PullStep::Pending, or panics if CanPend = No.

pub const fn is_ready(&self) -> bool

Returns true if the step is a PullStep::Ready.

pub const fn is_pending(&self) -> bool

Returns true if the step is a PullStep::Pending.

pub const fn is_ended(&self) -> bool

Returns true if the step is a PullStep::Ended.

pub fn try_convert_into<NewPend: Toggle, NewEnd: Toggle>( self, ) -> Option<PullStep<Item, Meta, NewPend, NewEnd>>

Tries to convert the CanPend and CanEnd type parameters, returning None if the conversion is invalid.

pub fn convert_into<NewPend: Toggle, NewEnd: Toggle>( self, ) -> PullStep<Item, Meta, NewPend, NewEnd>

Converts the CanPend and CanEnd type parameters, panicking if the conversion is invalid.

pub fn into_poll(self) -> Poll<Option<(Item, Meta)>>

Converts this PullStep into a Poll<Option<(Item, Meta)>>.

Trait Implementations

impl<Item: Clone, Meta: Clone, CanPend: Clone + Toggle, CanEnd: Clone + Toggle> Clone for PullStep<Item, Meta, CanPend, CanEnd>

fn clone(&self) -> PullStep<Item, Meta, CanPend, CanEnd>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<Item: Debug, Meta: Debug, CanPend: Debug + Toggle, CanEnd: Debug + Toggle> Debug for PullStep<Item, Meta, CanPend, CanEnd>

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

Formats the value using the given formatter.

impl<Item: Hash, Meta: Hash, CanPend: Hash + Toggle, CanEnd: Hash + Toggle> Hash for PullStep<Item, Meta, CanPend, CanEnd>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<Item: Ord, Meta: Ord, CanPend: Ord + Toggle, CanEnd: Ord + Toggle> Ord for PullStep<Item, Meta, CanPend, CanEnd>

fn cmp(&self, other: &PullStep<Item, Meta, CanPend, CanEnd>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<Item: PartialEq, Meta: PartialEq, CanPend: PartialEq + Toggle, CanEnd: PartialEq + Toggle> PartialEq for PullStep<Item, Meta, CanPend, CanEnd>

fn eq(&self, other: &PullStep<Item, Meta, CanPend, CanEnd>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<Item: PartialOrd, Meta: PartialOrd, CanPend: PartialOrd + Toggle, CanEnd: PartialOrd + Toggle> PartialOrd for PullStep<Item, Meta, CanPend, CanEnd>

fn partial_cmp( &self, other: &PullStep<Item, Meta, CanPend, CanEnd>, ) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<Item: Copy, Meta: Copy, CanPend: Copy + Toggle, CanEnd: Copy + Toggle> Copy for PullStep<Item, Meta, CanPend, CanEnd>

impl<Item: Eq, Meta: Eq, CanPend: Eq + Toggle, CanEnd: Eq + Toggle> Eq for PullStep<Item, Meta, CanPend, CanEnd>

impl<Item, Meta, CanPend: Toggle, CanEnd: Toggle> StructuralPartialEq for PullStep<Item, Meta, CanPend, CanEnd>