import * as p_di from "../../../interface/data.js";
export type Option<T extends p_di.Value> = readonly [string, T];
/**
 * ss means 'switch state'.
 * used to make the value T the context variable ('$')
 * given a tuple of a string and a value T,
 * the function takes the value T and calls back the callback ($c)
 * notice that the string part is never used
 *
 * example:
 *
 * switch ($.state[0]) {
 *     case 'on':
 *          return ss($.state, ($) => $.value)
 *     case 'off':
 *          return ss($.state, ($) => null)
 *     default: return au($.state[0])
 * }
 * @deprecated use 'option' instead
 */
export declare function ss<T extends p_di.Value, RT extends p_di.Value>(option: Option<T>, $c: ($: T) => RT): RT;
export declare function option<T extends p_di.Value, RT extends p_di.Value>(option: Option<T>, $c: ($: T) => RT): RT;
/**
 * au means 'assert unreachable'. Used in the 'default' clause of switch statements to ensure
 * during compile time that all possible cases have been implemented
 *
 * example:
 *
 * switch (x) {
 *     case '5':
 *         return 5
 *     default: return au(x)
 * }
 *
 * @param _x
 * @deprecated use exhaustive instead
 */
export declare function au<RT>(_x: never): RT;
export declare function exhaustive<RT>(_x: never): RT;