import { Scope } from "./abstractions";
import { UnaryTransformOp, UnaryTransformOpScoped } from "./transform";
export declare type TypeGuard<A, B extends A> = (value: A) => value is B;
export declare type Predicate<A> = (value: A) => boolean;
export declare function filter<A, B extends A>(fn: TypeGuard<A, B>): UnaryTransformOp<A, B>;
export declare function filter<A>(fn: Predicate<A>): UnaryTransformOp<A, A>;
export declare function filter<A, B extends A>(fn: TypeGuard<A, B>, scope: Scope): UnaryTransformOpScoped<A, B>;
export declare function filter<A>(fn: Predicate<A>, scope: Scope): UnaryTransformOpScoped<A>;