/**
 * Originally ported from https://github.com/zio/zio/blob/master/core/shared/src/main/scala/zio/Has.scala
 * by Michael Arnaldi and the Matechs Garage Contributors
 *
 * Copyright 2017-2020 John A. De Goes and the ZIO Contributors
 *
 * Copyright 2020 Michael Arnaldi and the Matechs Garage Contributors.
 */
import type { Option } from './Option';
/**
 * URI used in Has
 */
export declare const HasURI: unique symbol;
/**
 * Has signal presence of a specific service provided via Tag in the environment
 */
export interface Has<T> {
    [HasURI]: {
        _T: () => T;
    };
}
/**
 * URI used in Region
 */
export declare const RegionURI: unique symbol;
/**
 * Branding sub-environments
 */
export interface Region<K, T> {
    [RegionURI]: {
        _K: () => K;
        _T: () => T;
    };
}
/**
 * Extract the type of a class constructor
 */
export declare type ConstructorType<K extends Constructor<any>> = K extends {
    prototype: infer T;
} ? T : never;
export declare type Constructor<T> = Function & {
    prototype: T;
};
/**
 * Tag Encodes capabilities of reading and writing a service T into a generic environment
 */
export interface Tag<T> {
    _tag: 'Tag';
    _T: T;
    key: PropertyKey;
    def: boolean;
    overridable: () => Tag<T>;
    fixed: () => Tag<T>;
    refine: <T1 extends T>() => Tag<T1>;
    read: (r: Has<T>) => T;
    readOption: (r: unknown) => Option<T>;
    setKey: (s: PropertyKey) => Tag<T>;
    of: (_: T) => Has<T>;
}
/**
 * Extract the Has type from any augumented variant
 */
export declare type HasTag<T> = [T] extends [Tag<infer A>] ? Has<A> : never;
/**
 * Create a service entry Tag from a type and a URI
 */
export declare function tag<T extends Constructor<any>>(_: T): Tag<ConstructorType<T>>;
export declare function tag<T>(): Tag<T>;
/**
 * Get the service type of a Has
 */
export declare type ServiceType<T> = [T] extends [Has<infer A>] ? A : never;
/**
 * Replaces the service with the required Service Entry, in the specified environment
 */
export declare function replaceServiceIn<T>(_: Tag<T>, f: (t: T) => T): <R>(r: R & Has<T>) => R & Has<T>;
/**
 * Replaces the service with the required Service Entry, in the specified environment
 */
export declare function replaceServiceIn_<R, T>(r: R & Has<T>, _: Tag<T>, f: (t: T) => T): R & Has<T>;
/**
 * Flags the current Has to be overridable, when this is used subsequently provided
 * environments will override pre-existing. Useful to provide defaults.
 */
export declare function overridable<T>(h: Tag<T>): Tag<T>;
export declare function mergeEnvironments<T, R1>(_: Tag<T>, r: R1, t: T): R1 & Has<T>;
export declare class DerivationContext {
    readonly hasMap: Map<Tag<any>, Tag<any>>;
    derive<T, T2>(has: Tag<T>, f: () => Tag<T2>): Tag<T2>;
}
export declare const isTag: (u: unknown) => u is Tag<unknown>;
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