Struct SkipBlank 

pub struct SkipBlank<A = Same>(/* private fields */);

Leaves no value for blank strings.

Strings and lexical atoms that are empty or only whitespace (as defined by str::trim) are skipped: they leave the slot as it is. Everything else is deserialized with the adapter A (by default Same). Serialization uses the inner adapter.

Sequences and collections leave out elements without a value, which makes this an adapter for their elements: Vec<SkipBlank> drops the blank elements, in sequences as well as for keys that are given more than once (like tag=&tag=a in a query string or the whitespace between elements in XML). It can be combined with TrimWhitespace (which trims the other values) and Separated:

use deser::adapters::{Separated, SkipBlank, TrimWhitespace};
use deser::Deserialize;

#[derive(Deserialize)]
pub struct Config {
    // `a, ,b,` is `["a", "b"]`
    #[deser(as = Separated<',', SkipBlank<TrimWhitespace>>)]
    hosts: Vec<String>,
    // blank values are missing, which is `None`
    #[deser(as = SkipBlank<Option<_>>)]
    name: Option<String>,
}

For values that are not elements a blank string is a missing value: an optional is None, other types report the missing field (unless they have a default).

Trait Implementations

impl<'de, T: Send, A: Deserialize<'de, T>> Deserialize<'de, T> for SkipBlank<A>

fn deserialize_into<'out>( out: &'out mut Option<T>, state: &mut State, ) -> SinkHandle<'out, 'de>

Creates a sink that deserializes the value into the given slot.

fn expecting() -> Cow<'static, str>

Returns what the value expects, for error messages.

fn describe_type(d: &mut dyn Describe)

Describes the Rust shape of the type.

fn initial_value() -> Option<T>

Provides the value of a missing struct field.

fn deserialize_atom( slot: &mut Slot<T, Self>, atom: Atom<'_>, state: &mut State, ) -> Result<(), Error>

Deserializes an atom into the slot.

fn deserialize_borrowed_atom( slot: &mut Slot<T, Self>, atom: Atom<'de>, state: &mut State, ) -> Result<(), Error>

Deserializes an atom that borrows from the data being deserialized into the slot.

fn deserialize_update<'out>( value: &'out mut T, state: &mut State, ) -> SinkHandle<'out, 'de>

Creates a sink that updates an existing value.

impl<T: ?Sized, A: Serialize<T>> Serialize<T> for SkipBlank<A>

fn serialize<'a>(value: &'a T, state: &mut State) -> Result<Emit<'a>, Error>

Serializes the value.

fn finish(value: &T, state: &mut State) -> Result<(), Error>

Invoked after the serialization finished.

fn is_optional(value: &T) -> bool

Checks if the value represents an optional value.

fn container_shape(value: &T) -> ContainerShape

Returns the shape of the value if it’s a map or sequence.

fn describe(value: &T, d: &mut dyn Describe)

Describes the Rust shape of the value.