import * as postcss from 'postcss';
import { NodeProps } from '../node';
import type * as sassInternal from '../sass-internal';
import { Expression } from '.';
/**
 * The initializer properties for {@link NullExpression}.
 *
 * @category Expression
 */
export interface NullExpressionProps extends NodeProps {
    value: null;
    raws?: NullExpressionRaws;
}
/**
 * Raws indicating how to precisely serialize a {@link NullExpression}.
 *
 * @category Expression
 */
export interface NullExpressionRaws {
}
/**
 * An expression representing a null literal in Sass.
 *
 * @category Expression
 */
export declare class NullExpression extends Expression {
    readonly sassType: "null";
    raws: NullExpressionRaws;
    /**
     * The value of this expression. Always null.
     *
     * This is only present for consistency with other literal types.
     */
    get value(): null;
    set value(value: null);
    constructor(defaults?: Partial<NullExpressionProps>);
    /** @hidden */
    constructor(_: undefined, inner: sassInternal.NullExpression);
    clone(overrides?: Partial<NullExpressionProps>): this;
    toJSON(): object;
    /** @hidden */
    toJSON(_: string, inputs: Map<postcss.Input, number>): object;
    /** @hidden */
    toString(): string;
    /** @hidden */
    get nonStatementChildren(): ReadonlyArray<never>;
}