meta-log-db/dist/datalog/engine.js

Native database package for Meta-Log (ProLog, DataLog, R5RS)

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.DatalogEngine = void 0;
const fixed_point_js_1 = require("./fixed-point.js");
const fact_extraction_js_1 = require("./fact-extraction.js");
/**
 * DataLog Engine for Meta-Log Database
 */
class DatalogEngine {
    constructor() {
        this.facts = [];
        this.rules = [];
    }
    /**
     * Add facts to the database
     */
    addFacts(facts) {
        this.facts.push(...facts);
    }
    /**
     * Add a rule to the database
     */
    addRule(rule) {
        this.rules.push(rule);
    }
    /**
     * Build DataLog program from rules
     */
    buildProgram(rules) {
        return {
            rules: [...rules],
            facts: [...this.facts]
        };
    }
    /**
     * Query the database
     */
    async query(goal, program) {
        const targetProgram = program || this.buildProgram(this.rules);
        // Compute fixed point
        const allFacts = fixed_point_js_1.FixedPoint.compute(targetProgram);
        // Match goal against facts
        const parsedGoal = this.parseGoal(goal);
        const matchingFacts = allFacts.filter(fact => {
            if (fact.predicate !== parsedGoal.predicate) {
                return false;
            }
            if (fact.args.length !== parsedGoal.args.length) {
                return false;
            }
            // Match arguments (variables match anything)
            for (let i = 0; i < fact.args.length; i++) {
                const goalArg = parsedGoal.args[i];
                if (!goalArg.startsWith('?') && goalArg !== fact.args[i].toString()) {
                    return false;
                }
            }
            return true;
        });
        return { facts: matchingFacts };
    }
    /**
     * Compute fixed point
     */
    fixedPoint(program) {
        return fixed_point_js_1.FixedPoint.compute(program);
    }
    /**
     * Extract facts from canvas objects
     */
    extractFacts(objects) {
        return fact_extraction_js_1.FactExtraction.extractFromCanvas(objects);
    }
    /**
     * Parse goal string
     */
    parseGoal(goal) {
        const match = goal.match(/^(\w+)\((.*)\)$/);
        if (match) {
            const predicate = match[1];
            const argsStr = match[2];
            const args = argsStr ? argsStr.split(',').map(s => s.trim()) : [];
            return { predicate, args };
        }
        return { predicate: goal, args: [] };
    }
    /**
     * Get all facts
     */
    getFacts() {
        return [...this.facts];
    }
    /**
     * Get all rules
     */
    getRules() {
        return [...this.rules];
    }
    /**
     * Clear database
     */
    clear() {
        this.facts = [];
        this.rules = [];
    }
}
exports.DatalogEngine = DatalogEngine;
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