Enum PatternConstraint 

pub enum PatternConstraint {
    Simple {
        field: String,
        operator: String,
        value: FactValue,
    },
    Binding {
        field: String,
        variable: Variable,
    },
    Variable {
        field: String,
        operator: String,
        variable: Variable,
    },
    MultiField {
        field: String,
        variable: Option<Variable>,
        operator: MultifieldOp,
        value: Option<FactValue>,
    },
}

Pattern constraint with optional variable binding

Variants

Simple

Simple constraint: field op value

Fields

field: String

operator: String

value: FactValue

Binding

Binding constraint: field = $var (binds value to variable)

Fields

field: String

variable: Variable

Variable

Variable constraint: field op $var (compare with bound variable)

Fields

field: String

operator: String

variable: Variable

MultiField

Multi-field constraint: pattern matching on arrays/collections

Examples:

• Order.items $?all_items - Collect all items (Collect)
• Product.tags contains "electronics" - Check containment (Contains)
• Order.items count > 0 - Get array length (Count)

Fields

field: String

variable: Option<Variable>

operator: MultifieldOp

value: Option<FactValue>

Implementations

impl PatternConstraint

pub fn simple(field: String, operator: String, value: FactValue) -> Self

Create simple constraint

pub fn binding(field: String, variable: Variable) -> Self

Create binding constraint

pub fn variable(field: String, operator: String, variable: Variable) -> Self

Create variable constraint

pub fn multifield( field: String, operator: MultifieldOp, variable: Option<Variable>, value: Option<FactValue>, ) -> Self

Create multi-field constraint

pub fn evaluate( &self, facts: &TypedFacts, bindings: &HashMap<Variable, FactValue>, ) -> Option<HashMap<Variable, FactValue>>

Evaluate constraint against facts and bindings

Trait Implementations

impl Clone for PatternConstraint

fn clone(&self) -> PatternConstraint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PatternConstraint

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

Formats the value using the given formatter.