Struct Justification 

pub struct Justification {
    pub fact_handle: FactHandle,
    pub justification_type: JustificationType,
    pub source_rule: Option<String>,
    pub premise_facts: Vec<FactHandle>,
    pub created_at: Instant,
    pub id: u64,
}

Justification records WHY a fact exists

A fact can have multiple justifications (multiple rules can derive the same fact). The fact is only retracted when ALL justifications are removed.

Fields

fact_handle: FactHandle

The fact being justified

justification_type: JustificationType

Type of justification

source_rule: Option<String>

Rule that created this fact (if logical)

premise_facts: Vec<FactHandle>

Premise facts that caused this derivation If any of these are retracted, this justification is invalid

created_at: Instant

When this justification was created

id: u64

Unique ID for this justification

Implementations

impl Justification

pub fn explicit(fact_handle: FactHandle, id: u64) -> Self

Create a new explicit justification (user asserted)

pub fn logical( fact_handle: FactHandle, source_rule: String, premise_facts: Vec<FactHandle>, id: u64, ) -> Self

Create a new logical justification (rule derived)

pub fn is_valid(&self, retracted_facts: &HashSet<FactHandle>) -> bool

Check if this justification is still valid (all premise facts still exist)

Trait Implementations

impl Clone for Justification

fn clone(&self) -> Justification

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Justification

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

Formats the value using the given formatter.