import type { IAction, IActorArgs, IActorOutput, IActorTest, Mediate } from '@comunica/core';
import { Actor } from '@comunica/core';
import type { Bindings } from '@comunica/types';
import type * as RDF from '@rdfjs/types';
/**
 * A comunica actor for hash-bindings events.
 *
 * Actor types:
 * * Input:  IActionHashBindings:      Metadata for selecting a hash function.
 * * Test:   IActorTest:
 * * Output: IActorHashBindingsOutput: The resulting hash function.
 *
 * @see IActionHashBindings
 * @see IActorHashBindingsTest
 * @see IActorHashBindingsOutput
 */
export declare abstract class ActorHashBindings<TS = undefined> extends Actor<IActionHashBindings, IActorTest, IActorHashBindingsOutput, TS> {
    /**
     * @param args -
     *   \ @defaultNested {<default_bus> a <cc:components/Bus.jsonld#Bus>} bus
     *   \ @defaultNested {Failed to obtaining hash functions for bindings} busFailMessage
     */
    constructor(args: IActorHashBindingsArgs<TS>);
}
export interface IActionHashBindings extends IAction {
}
export interface IActorHashBindingsOutput extends IActorOutput {
    /**
     * A number-based hash factory of the given object.
     * It is recommended to always return 32-bit numbers to enable SMI optimization.
     *
     * Hash functions could produce collisions for non-equal bindings.
     *
     * @param {Bindings} bindings The bindings to hash.
     * @return {string} The object's hash.
     */
    hashFunction: HashFunction;
}
export type HashFunction = (bindings: Bindings, variables: Iterable<RDF.Variable>) => number;
export type IActorHashBindingsArgs<TS = undefined> = IActorArgs<IActionHashBindings, IActorTest, IActorHashBindingsOutput, TS>;
export type MediatorHashBindings = Mediate<IActionHashBindings, IActorHashBindingsOutput>;