import * as RDF from "@rdfjs/types";
import { IBindings, ISettings } from "sparqljson-parse";
/**
 * Converts SPARQL JSON results to a tree-based structure by splitting variables on a certain delimiter.
 */
export declare class Converter {
    private readonly delimiter;
    private readonly parser;
    private readonly materializeRdfJsTerms;
    constructor(settings?: IConverterSettings);
    /**
     * Adds a value to a tree.
     * @param tree A tree datastructure.
     * @param {string[]} path The path of keys in the tree.
     * @param {Term} value A value to add.
     * @param {string} lastKeyPath The accumulated key path (separated by the given delimiter)
     *                             through recursive calls, can be empty.
     * @param {ISchema} schema A schema.
     * @param {string} delimiter The string to join key paths by.
     */
    static addValueToTree(tree: any, path: string[], value: RDF.Term, lastKeyPath: string, schema: ISchema, delimiter: string): void;
    /**
     * Recursively merge the two given trees.
     * @param tree1 A first tree (has key priority on literals).
     * @param tree2 A second tree. All arrays will/should only have a single element.
     * @return {any} The merged tree.
     */
    static mergeTrees(tree1: any, tree2: any): IMergeResult;
    /**
     * Materialize all RDF terms in the given tree to raw values.
     * This does not mutate the original tree.
     * @param tree A tree.
     * @return {any} A materialized tree.
     */
    static materializeTree(tree: any): any;
    /**
     * Convert a complete SPARQL JSON response to a GraphQL results tree.
     * @param sparqlResponse A SPARQL JSON response.
     * @param {ISchema} schema A schema.
     * @return {any} A GraphQL results tree.
     */
    sparqlJsonResultsToTree(sparqlResponse: any, schema?: ISchema): any;
    /**
     * Convert an array of bindings to a GraphQL results tree.
     * @param {IBindings[]} bindingsArray An array of bindings.
     * @param {ISchema} schema A schema.
     * @return {any} A GraphQL results tree.
     */
    bindingsToTree(bindingsArray: IBindings[], schema: ISchema): any;
}
/**
 * Constructor settings object interface for {@link Converter}.
 */
export interface IConverterSettings extends ISettings {
    /**
     * The string to split variable names by.
     * Defaults to '_'.
     */
    delimiter?: string;
    /**
     * If RDFJS terms should be converted to their raw value.
     * Defaults to false.
     */
    materializeRdfJsTerms?: boolean;
}
export interface ISchema {
    /**
     * Defines for each variable if the tree structure should have an array or a singular value for its values.
     * If true, a single value is represented, without array.
     * Defaults to false (arrays), due to the open-world-assumption in RDF.
     */
    singularizeVariables: {
        [id: string]: boolean;
    };
}
export interface IMergeResult {
    /**
     * If the merging was successful.
     * If not, information was withheld from the result.
     */
    valid: boolean;
    /**
     * The result of the merge.
     */
    result: any;
}