Enum OptionalValue

pub enum OptionalValue<T> {
    Some(T),
    None,
}

A smart contract argument or result that can be missing.

If arguments stop before this argument, None will be returned. As an endpoint result, the contract decides if it produces it or not.

As a principle, optional arguments or results should come last, otherwise there is ambiguity as to how to interpret what comes after.

Variants

Some(T)

None

Implementations

impl<T> OptionalValue<T>

pub fn into_option(self) -> Option<T>

pub fn is_some(&self) -> bool

pub fn is_none(&self) -> bool

Trait Implementations

impl<T> Clone for OptionalValue<T>

where T: Clone,

fn clone(&self) -> OptionalValue<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T> Debug for OptionalValue<T>

where T: Debug,

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

Formats the value using the given formatter.

impl<T> From<Option<T>> for OptionalValue<T>

fn from(v: Option<T>) -> OptionalValue<T>

Converts to this type from the input type.

impl<T> TopDecodeMulti for OptionalValue<T>

where T: TopDecodeMulti,

fn multi_decode_or_handle_err<I, H>( input: &mut I, h: H, ) -> Result<OptionalValue<T>, <H as DecodeErrorHandler>::HandledErr>

where I: TopDecodeMultiInput, H: DecodeErrorHandler,

const IS_SINGLE_VALUE: bool = false

Used to optimize single value loading of endpoint arguments.

fn multi_decode<I>(input: &mut I) -> Result<Self, DecodeError>

where I: TopDecodeMultiInput,

impl<T> TopEncodeMulti for OptionalValue<T>

where T: TopEncodeMulti,

fn multi_encode_or_handle_err<O, H>( &self, output: &mut O, h: H, ) -> Result<(), <H as EncodeErrorHandler>::HandledErr>

where O: TopEncodeMultiOutput, H: EncodeErrorHandler,

Version of top_encode that can handle errors as soon as they occur. For instance in can exit immediately and make sure that if it returns, it is a success. By not deferring error handling, this can lead to somewhat smaller bytecode.

fn multi_encode<O>(&self, output: &mut O) -> Result<(), EncodeError>

where O: TopEncodeMultiOutput,

Attempt to serialize the value to ouput.

impl<T: TypeAbi> TypeAbi for OptionalValue<T>

type Unmanaged = OptionalValue<<T as TypeAbi>::Unmanaged>

fn type_name() -> TypeName

fn type_name_rust() -> TypeName

fn provide_type_descriptions<TDC: TypeDescriptionContainer>( accumulator: &mut TDC, )

A type can provide more than its own name. For instance, a struct can also provide the descriptions of the type of its fields. TypeAbi doesn’t care for the exact accumulator type, which is abstracted by the TypeDescriptionContainer trait.

fn type_names() -> TypeNames

impl<T, U> TypeAbiFrom<OptionalValue<U>> for OptionalValue<T>

where T: TypeAbiFrom<U>,