Enum Cardinality 

pub enum Cardinality {
    Required,
    Optional,
    Repeatable,
}

How many neighbours of a given NeighborRole a terminal expects.

A Vec<NeighborReq> (rather than an integer count) is used deliberately so future requirements can be expressed compositionally without an arithmetic model.

Variants

Required

Must be present — its absence is a completeness error.

Optional

May be present; never an error if absent.

Repeatable

Zero or more — informational only, never an error.

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 PartialEq for Cardinality

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for Cardinality