Module multifield 

Multi-field (Multislot) Variables - CLIPS-inspired Feature

This module implements CLIPS-style multi-field variables for pattern matching on arrays and collections. Multi-field variables allow:

• Collecting all values: Order.items $?all_items
• Checking containment: Product.tags contains "electronics"
• Getting array length: Order.items count > 0
• Accessing elements: Order.items first, Order.items last

CLIPS Reference

(deftemplate order
  (slot order-id)
  (multislot items))

(defrule process-order
  (order (order-id ?id) (items $?all-items))
  =>
  (foreach ?item $?all-items
    (process ?item)))

Rust API

use rust_rule_engine::rete::{MultifieldOp, PatternConstraint};

// Pattern: Order.items $?all_items
let constraint = PatternConstraint::MultiField {
    field: "items".to_string(),
    variable: Some("$?all_items".to_string()),
    operator: MultifieldOp::Collect,
    value: None,
};

// Pattern: Product.tags contains "electronics"
let constraint = PatternConstraint::MultiField {
    field: "tags".to_string(),
    variable: None,
    operator: MultifieldOp::Contains,
    value: Some(FactValue::String("electronics".to_string())),
};

Enums

MultifieldOp

Multi-field operations for pattern matching

Functions

evaluate_multifield_pattern

Helper function to evaluate multi-field patterns in rules

is_multifield_variable

Check if a string is a multi-field variable

parse_multifield_variable

Parse multi-field variable syntax