Struct efficient_enum::EfficientOption

pub struct EfficientOption<A, TaggingMethod = TagMSB>(_, _) where A: TaggableValue<TaggingMethod, Two>;

An option type similar to Option<A>, but where no extra data is used. Instead, some of the space in A is used to "tag the union".

The one true downside is that it is impossible to get &A from &EfficientOption. The reason for this is that doing so would expose the private tag info.

Methods

impl<TaggingMethod, A> EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn new(a: Option<A>) -> Self

Constructs a new EfficientOption

fn none() -> Self

Constructs an empty EfficientOption

fn some(a: A) -> Self

Constructs an EfficientOption from an A value

fn destructure(self) -> Option<A>

Destructures an EfficientOption

fn is_some(&self) -> bool

Returns true if the option is a Some value.

fn is_none(&self) -> bool

Returns true if the option is a None value.

fn map<R, F: FnOnce(Option<&mut A>) -> R>(&mut self, f: F) -> R

Maps the value to a result

Trait Implementations

impl<TaggingMethod, A: Clone> Clone for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<TaggingMethod, A: Copy> Copy for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

impl<TaggingMethod, A> Default for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn default() -> Self

Returns the "default value" for a type.

impl<TaggingMethod, A: Debug> Debug for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

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

Formats the value using the given formatter.

impl<TaggingMethod, A: PartialEq> PartialEq for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn eq(&self, other: &Self) -> bool

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

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

This method tests for !=.

impl<TaggingMethod, A: Eq> Eq for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

impl<TaggingMethod, A: Hash> Hash for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

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

Feeds this value into the state given, updating the hasher as necessary.

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

Feeds a slice of this type into the state provided.

impl<TaggingMethod, A> From<Option<A>> for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn from(a: Option<A>) -> Self

Performs the conversion.

impl<TaggingMethod, A> Into<Option<A>> for EfficientOption<A, TaggingMethod> where A: TaggableValue<TaggingMethod, Two>

fn into(self) -> Option<A>

Performs the conversion.