import { AnyExpression, Expression } from '../../expressions';
import { CharacterArg, TextType } from '..';
import { Type } from '../index';
import { ConstraintConfig } from '../../functions';
export declare const BOOLEAN: () => BooleanType<true>;
export declare type BooleanArg = BooleanType['argument'];
export interface BooleanType<R extends boolean = any> extends Type<'BOOLEAN', R> {
    expression: BooleanExpression<R>;
    argument: BooleanExpression | this['input'];
    required(conf?: ConstraintConfig): BooleanType<false>;
}
export interface BooleanExpression<R extends boolean = any> extends AnyExpression<BooleanType<R>> {
    concat(arg: CharacterArg): Expression<TextType<R>>;
}