import * as postcss from 'postcss';
import { NodeProps } from '../node';
import type * as sassInternal from '../sass-internal';
import { AnyExpression, Expression, ExpressionProps } from '.';
/** Different unary operations supported by Sass. */
export type UnaryOperator = '+' | '-' | '/' | 'not';
/**
 * The initializer properties for {@link UnaryOperationExpression}.
 *
 * @category Expression
 */
export interface UnaryOperationExpressionProps extends NodeProps {
    operator: UnaryOperator;
    operand: AnyExpression | ExpressionProps;
    raws?: UnaryOperationExpressionRaws;
}
/**
 * Raws indicating how to precisely serialize a {@link UnaryOperationExpression}.
 *
 * @category Expression
 */
export interface UnaryOperationExpressionRaws {
    /** The whitespace between the operator and operand. */
    between?: string;
}
/**
 * An expression representing a unary operation in Sass.
 *
 * @category Expression
 */
export declare class UnaryOperationExpression extends Expression {
    readonly sassType: "unary-operation";
    raws: UnaryOperationExpressionRaws;
    /** Which operator this operation uses. */
    get operator(): UnaryOperator;
    set operator(operator: UnaryOperator);
    private _operator;
    /** The expression that this operation acts on. */
    get operand(): AnyExpression;
    set operand(operand: AnyExpression | ExpressionProps);
    private _operand;
    constructor(defaults: UnaryOperationExpressionProps);
    /** @hidden */
    constructor(_: undefined, inner: sassInternal.UnaryOperationExpression);
    clone(overrides?: Partial<UnaryOperationExpressionProps>): this;
    toJSON(): object;
    /** @hidden */
    toJSON(_: string, inputs: Map<postcss.Input, number>): object;
    /** @hidden */
    toString(): string;
    /** @hidden */
    get nonStatementChildren(): ReadonlyArray<AnyExpression>;
}