Struct Rule 

pub struct Rule {
    pub head: Atom,
    pub body: Vec<BodyPredicate>,
    pub constraints: Vec<Constraint>,
}

Represents a single Datalog rule

Examples

reach(y) :- reach(x), edge(x, y).

Fields

head: Atom

body: Vec<BodyPredicate>

constraints: Vec<Constraint>

Implementations

impl Rule

pub fn new( head: Atom, body: Vec<BodyPredicate>, constraints: Vec<Constraint>, ) -> Self

Create a new rule

pub fn new_simple( head: Atom, body: Vec<Atom>, constraints: Vec<Constraint>, ) -> Self

Create a rule with only positive body atoms (no negation)

pub fn is_safe(&self) -> bool

Check if this rule is safe (all head variables appear in positive body atoms)

pub fn positive_body_variables(&self) -> HashSet<String>

Get all variables in positive body atoms

pub fn variables(&self) -> HashSet<String>

Get all variables in this rule

pub fn is_recursive(&self) -> bool

Check if this rule is recursive (head relation appears in body)

pub fn positive_body_atoms(&self) -> Vec<&Atom>

Get all positive body atoms

pub fn negated_body_atoms(&self) -> Vec<&Atom>

Get all negated body atoms

Trait Implementations

impl Clone for Rule

fn clone(&self) -> Rule

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Rule

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

Formats the value using the given formatter.