Enum Cardinality 

pub enum Cardinality {
    Required,
    Optional,
    Repeated,
}

How many of one member there are.

Three rows and no fourth: the wire roads below stand over ONE occurrence whatever supplied it, so a cardinality decides how many times a road runs and never what the road writes.

Variants

Required

Exactly one, written where the shape declares it.

Optional

One or none, written behind a presence byte.

Repeated

As many as the value holds, written behind a framed count.

Implementations

impl Cardinality

pub const ALL: &'static [Self]

The complete roster, in declaration order.

pub const fn name(self) -> &'static str

This row’s declared name.

Trait Implementations

impl Clone for Cardinality

fn clone(&self) -> Cardinality

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Cardinality

impl Debug for Cardinality

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

Formats the value using the given formatter.

impl Eq for Cardinality

impl Hash for Cardinality

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

Feeds this value into the given Hasher.

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

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Cardinality

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for Cardinality