/**
 * @since 1.2.0
 */
import { At, Lens } from '..';
import * as S from 'fp-ts/es6/Set';
/**
 * @category constructor
 * @since 1.2.0
 */
export function atSet(E) {
    var elemE = S.elem(E);
    var insertE = S.insert(E);
    var removeE = S.remove(E);
    return new At(function (at) {
        var insertEAt = insertE(at);
        var removeEAt = removeE(at);
        return new Lens(function (s) { return elemE(at, s); }, function (a) { return function (s) { return (a ? insertEAt(s) : removeEAt(s)); }; });
    });
}