/**
 * validators - a declarative, framework-free validation-rule library for SvForm
 * (and any editor). Each rule builder returns a `Validator`: a pure function
 * `(value, allValues?) => errorMessage | null`. Compose them per field; the form
 * runs them in order and shows the first failure. Parity: Smart `smart.validator`
 * (required / email / pattern / min / max / range / stringLength / compare ...).
 *
 * ```ts
 * import { rules } from '@svgrid/grid'
 * const field = { name: 'email', label: 'Email', rules: [rules.required(), rules.email()] }
 * ```
 */
export type Validator = (value: any, values?: Record<string, any>) => string | null | undefined;
export type RuleOptions = {
    message?: string;
};
export type CompareOp = '==' | '===' | '!=' | '<' | '<=' | '>' | '>=';
/** Empty for validation purposes: null/undefined, '', or an empty array. */
export declare function isEmptyValue(v: any): boolean;
/** The declarative rule builders. Every builder skips empty values (except
 *  `required`) so optional fields validate format only when filled. */
export declare const rules: {
    required: (o?: RuleOptions) => Validator;
    email: (o?: RuleOptions) => Validator;
    url: (o?: RuleOptions) => Validator;
    zipCode: (o?: RuleOptions) => Validator;
    pattern: (re: RegExp, o?: RuleOptions) => Validator;
    numeric: (o?: RuleOptions) => Validator;
    integer: (o?: RuleOptions) => Validator;
    min: (n: number, o?: RuleOptions) => Validator;
    max: (n: number, o?: RuleOptions) => Validator;
    range: (lo: number, hi: number, o?: RuleOptions) => Validator;
    minLength: (n: number, o?: RuleOptions) => Validator;
    maxLength: (n: number, o?: RuleOptions) => Validator;
    stringLength: (lo: number, hi: number, o?: RuleOptions) => Validator;
    oneOf: (allowed: ReadonlyArray<string | number>, o?: RuleOptions) => Validator;
    /** Compare against another field's value (cross-field): e.g. confirm password. */
    compare: (otherField: string, op?: CompareOp, o?: RuleOptions) => Validator;
    /** Wrap an arbitrary predicate/function as a rule. */
    custom: (fn: Validator) => Validator;
};
/** Run a list of rules against a value; return the first error message, or null. */
export declare function runRules(value: any, ruleList: ReadonlyArray<Validator> | undefined, values?: Record<string, any>): string | null;