import type { LiteralNode, RefsStore } from '@vinejs/compiler/types';
import type { FieldOptions, ParserOptions, ConstructableSchema, WithJSONSchema } from '../../types.js';
import { OTYPE, COTYPE, PARSE, ITYPE, SUBTYPE, UNIQUE_NAME, IS_OF_TYPE } from '../../symbols.js';
import { type JSONSchema7 } from 'json-schema';
/**
 * VineNull represents a schema type that only accepts null values.
 * Typically used inside union types to explicitly allow null as a valid value.
 *
 * @example
 * const schema = vine.union([
 *   vine.string(),
 *   vine.null()
 * ])
 *
 * const result = await vine.validate({
 *   schema,
 *   data: null
 * })
 */
export declare class VineNull implements ConstructableSchema<null, null, null>, WithJSONSchema {
    /**
     * The input type of the schema (type-only property)
     */
    [ITYPE]: null;
    /**
     * The output type of the schema (type-only property)
     */
    [OTYPE]: null;
    /**
     * The camelCase output type of the schema (type-only property)
     */
    [COTYPE]: null;
    /**
     * The subtype identifier for the literal schema field
     */
    [SUBTYPE]: string;
    /**
     * Unique name identifier for union type resolution
     */
    [UNIQUE_NAME]: string;
    /**
     * Type checker function to determine if a value is null.
     * Required for "unionOfTypes" functionality.
     *
     * @param value - The value to check
     * @returns True if the value is null
     */
    [IS_OF_TYPE]: (value: unknown) => value is null;
    /**
     * Field configuration options
     */
    protected options: FieldOptions;
    /**
     * Creates a new VineNull instance with optional configuration.
     *
     * @param options - Field options like bail mode (defaults allow null)
     */
    constructor(options?: Partial<FieldOptions>);
    /**
     * Creates a shallow clone of the field options.
     */
    protected cloneOptions(): FieldOptions;
    /**
     * Clones the VineNull schema type. The applied options
     * are copied to the new instance.
     *
     * @returns A cloned instance of this VineNull schema
     */
    clone(): this;
    /**
     * Converts the schema to JSON Schema format.
     * Returns a schema with type 'null'.
     */
    toJSONSchema(): JSONSchema7;
    /**
     * Compiles the schema type to a compiler node for validation.
     *
     * @param propertyName - The name of the property being validated
     * @param refs - Reference store for tracking parsers and validators
     * @param options - Parser options including camelCase conversion
     */
    [PARSE](propertyName: string, refs: RefsStore, options: ParserOptions): LiteralNode & {
        subtype: string;
    };
}