import { Logger } from '../util/logger';
import { ReferenceResolver } from '../reference-resolver';
import { PolicyResolver } from '../util/policy-resolver';
import { Step } from '../types';
export declare class _UnknownReferenceError extends Error {
    constructor(message: string);
}
export declare class SafeExpressionEvaluator {
    private referenceResolver;
    private static readonly MAX_EXPRESSION_LENGTH;
    private logger;
    private policyResolver?;
    private defaultExpressionTimeout;
    private static ensureNumbers;
    private static ensureSameType;
    private static checkDivisionByZero;
    static readonly OPERATORS: {
        readonly '+': (a: any, b: any) => any;
        readonly '-': (a: any, b: any) => number;
        readonly '*': (a: any, b: any) => number;
        readonly '/': (a: any, b: any) => number;
        readonly '%': (a: any, b: any) => number;
        readonly '==': (a: any, b: any) => boolean;
        readonly '===': (a: any, b: any) => boolean;
        readonly '!=': (a: any, b: any) => boolean;
        readonly '!==': (a: any, b: any) => boolean;
        readonly '>': (a: any, b: any) => boolean;
        readonly '>=': (a: any, b: any) => boolean;
        readonly '<': (a: any, b: any) => boolean;
        readonly '<=': (a: any, b: any) => boolean;
        readonly '&&': (a: any, b: any) => any;
        readonly '||': (a: any, b: any) => any;
        readonly '??': (a: any, b: any) => any;
    };
    private static readonly ALLOWED_FUNCTIONS;
    constructor(logger: Logger, referenceResolver: ReferenceResolver, policyResolver?: PolicyResolver);
    /**
     * Set the policy resolver to be used for expression timeouts
     * @param policyResolver The policy resolver
     */
    setPolicyResolver(policyResolver: PolicyResolver): void;
    /**
     * Get the current expression timeout in milliseconds
     * @param step Optional step context for timeout resolution
     * @param stepType Optional step type for timeout resolution
     * @returns The resolved timeout value
     */
    getExpressionTimeout(step?: Step, stepType?: string): number;
    evaluate(expression: string, context: Record<string, any>, step?: Step): any;
    private validateExpression;
    private checkTimeout;
    /**
     * Helper method to convert token values to JavaScript literal values
     */
    private tokenToLiteral;
    private parse;
    private parseExpression;
    private getPrecedence;
    private parseGroupedElements;
    private parseArrayElements;
    private parseObjectProperties;
    private buildReferencePath;
    private evaluateAst;
    private handleReferenceError;
    private static isSpecialVariable;
    extractReferences(expression: string): string[];
}