import { CompositeSource } from '../source-elements/composite-source';
import { SourceQueryElement } from './source-query-element';
/**
 * e.g. `compose(source_a, source_b)`
 */
export declare class SQCompose extends SourceQueryElement {
    readonly sources: SourceQueryElement[];
    elementType: string;
    asSource?: CompositeSource;
    constructor(sources: SourceQueryElement[]);
    getSource(): CompositeSource | undefined;
    isSource(): boolean;
}