Trait SeqAccess

pub trait SeqAccess<'de> {
    type Error: Error;

    // Required method
    fn next_element_seed<T>(
        &mut self,
        seed: T,
    ) -> Result<Option<<T as DeserializeSeed<'de>>::Value>, Self::Error>
       where T: DeserializeSeed<'de>;

    // Provided methods
    fn next_element<T>(&mut self) -> Result<Option<T>, Self::Error>
       where T: Deserialize<'de> { ... }
    fn size_hint(&self) -> Option<usize> { ... }
}

Provides a Visitor access to each element of a sequence in the input.

This is a trait that a Deserializer passes to a Visitor implementation, which deserializes each item in a sequence.

Lifetime

The 'de lifetime of this trait is the lifetime of data that may be borrowed by deserialized sequence elements. See the page Understanding deserializer lifetimes for a more detailed explanation of these lifetimes.

Example implementation

The example data format presented on the website demonstrates an implementation of SeqAccess for a basic JSON data format.

Required Associated Types

type Error: Error

The error type that can be returned if some error occurs during deserialization.

Required Methods

fn next_element_seed<T>( &mut self, seed: T, ) -> Result<Option<<T as DeserializeSeed<'de>>::Value>, Self::Error>

where T: DeserializeSeed<'de>,

This returns Ok(Some(value)) for the next value in the sequence, or Ok(None) if there are no more remaining items.

Deserialize implementations should typically use SeqAccess::next_element instead.

Provided Methods

fn next_element<T>(&mut self) -> Result<Option<T>, Self::Error>

where T: Deserialize<'de>,

This returns Ok(Some(value)) for the next value in the sequence, or Ok(None) if there are no more remaining items.

This method exists as a convenience for Deserialize implementations. SeqAccess implementations should not override the default behavior.

fn size_hint(&self) -> Option<usize>

Returns the number of elements remaining in the sequence, if known.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<'de, A> SeqAccess<'de> for &mut A

where A: SeqAccess<'de> + ?Sized,

type Error = <A as SeqAccess<'de>>::Error

fn next_element_seed<T>( &mut self, seed: T, ) -> Result<Option<<T as DeserializeSeed<'de>>::Value>, <&mut A as SeqAccess<'de>>::Error>

where T: DeserializeSeed<'de>,

fn next_element<T>( &mut self, ) -> Result<Option<T>, <&mut A as SeqAccess<'de>>::Error>

where T: Deserialize<'de>,

fn size_hint(&self) -> Option<usize>

Implementors

impl<'de, I, E> SeqAccess<'de> for MapDeserializer<'de, I, E>

where I: Iterator, <I as Iterator>::Item: Pair, <<I as Iterator>::Item as Pair>::First: IntoDeserializer<'de, E>, <<I as Iterator>::Item as Pair>::Second: IntoDeserializer<'de, E>, E: Error,

type Error = E

impl<'de, I, T, E> SeqAccess<'de> for SeqDeserializer<I, E>

where I: Iterator<Item = T>, T: IntoDeserializer<'de, E>, E: Error,

type Error = E