Enum TypeRelation 

pub enum TypeRelation {
    Subtype,
    Equal,
    Supertype,
}

Variants

Subtype

Strict subtype

Equal

Supertype

Strict supertype

Implementations

impl TypeRelation

pub fn reverse(self) -> Self

pub fn combine(self, other: Self) -> Option<Self>

Combines two partial relation results.

While computing the relation of two types, sometimes it has to be done in multiple steps, e.g. oneof, record.

• In both cases, one may start with Self::Equal before processing any type parameters.
• If both types are empty (e.g. record<> with no columns, oneof<> with no variants), Self::Equal is the correct result without requiring further checks.
• As items are checked, the result of these checks may not form a coherent result. e.g.: lhs = record<a: int, b: int> and rhs = record<a: int, c: int>
  • both lhs and rhs have an a: int column. lhs and rhs might be Equal
  • lhs has a b: int column, which rhs does not. This makes lhs the more specific type between the two, thus lhs might be a Subtype of rhs
  • lhs does not have a b: int column, which rhs does. This makes rhs the more specific type between the two, thus lhs might be a Supertype of rhs
• If there are conflicting results, returns None

Trait Implementations

impl Clone for TypeRelation

fn clone(&self) -> TypeRelation

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TypeRelation

impl Debug for TypeRelation

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

Formats the value using the given formatter.

impl Eq for TypeRelation

impl PartialEq for TypeRelation

fn eq(&self, other: &TypeRelation) -> 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 TypeRelation