Struct Opt 

pub struct Opt<W>(/* private fields */);

An optional field through W.

Trait Implementations

impl<F, W: With<F>> With<Option<F>> for Opt<W>

fn shape() -> Shape

fn read(v: &ValueRef<'_>, cx: &mut Reader<'_>) -> Option<Option<F>>

fn write(f: &Option<F>) -> Value

fn absent() -> Option<Option<F>>

The field’s value when it isn’t there (None: it’s required).

fn skip(f: &Option<F>) -> bool

Whether a struct leaves the field out.