Enum EvidenceLevel 

pub enum EvidenceLevel {
    Known,
    Uncertain,
    Reported,
    Paradox,
}

Evidence levels in the type system.

Evidence forms a lattice: Known (!) < Uncertain (?) < Reported (~) < Paradox (‽)

Operations combine evidence levels using join (⊔): a + b : join(evidence(a), evidence(b))

Variants

Known

Direct knowledge - computed locally, verified

Uncertain

Uncertain - inferred, possible, not verified

Reported

Reported - from external source, hearsay

Paradox

Paradox - contradictory information

Implementations

impl EvidenceLevel

pub fn join(self, other: Self) -> Self

Join two evidence levels (least upper bound in lattice)

pub fn meet(self, other: Self) -> Self

Meet two evidence levels (greatest lower bound)

pub fn from_ast(e: Evidentiality) -> Self

Convert from AST representation

pub fn symbol(&self) -> &'static str

Symbol representation

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

Human-readable name

pub fn satisfies(self, required: Self) -> bool

Check if this evidence level can satisfy a required level.

Evidence is covariant: you can pass more certain data where less certain is expected. Known (!) can satisfy any requirement. Reported (~) can only satisfy Reported or Paradox requirements.

Returns true if self (actual) can be used where required is expected.

Trait Implementations

impl Clone for EvidenceLevel

fn clone(&self) -> EvidenceLevel

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EvidenceLevel

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

Formats the value using the given formatter.

impl Ord for EvidenceLevel

fn cmp(&self, other: &EvidenceLevel) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for EvidenceLevel

fn eq(&self, other: &EvidenceLevel) -> 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 PartialOrd for EvidenceLevel

fn partial_cmp(&self, other: &EvidenceLevel) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Copy for EvidenceLevel

impl Eq for EvidenceLevel

impl StructuralPartialEq for EvidenceLevel