JSTests/test262/test/language/expressions/exponentiation/exp-operator-precedence-unary-expression-semantics.js

// Copyright (C) 2016 Rick Waldron. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
author: Rick Waldron
esid: sec-unary-operators
description: Exponentiation Operator expression precedence of unary operators
info: |
  ExponentiationExpression :
    UnaryExpression
    ...

  UnaryExpression :
    ...
    `delete` UnaryExpression
    `void` UnaryExpression
    `typeof` UnaryExpression
    `+` UnaryExpression
    `-` UnaryExpression
    `~` UnaryExpression
    `!` UnaryExpression
---*/

assert.sameValue(-(3 ** 2), -9, "-(3 ** 2) === -9");
assert.sameValue(+(3 ** 2), 9, "+(3 ** 2) === 9");
assert.sameValue(~(3 ** 2), -10, "~(3 ** 2) === -10");
assert.sameValue(!(3 ** 2), false, "!(3 ** 2) === false");


assert.sameValue(2 ** -2, 0.25);

var o = { p: 1 };

assert.sameValue(2 ** delete o.p, 2, "delete o.p -> true -> ToNumber(true) -> 1");
assert.sameValue(2 ** void 1, NaN, "void 1 -> undefined -> ToNumber(undefined) -> NaN");
assert.sameValue(2 ** typeof 1, NaN, "typeof 1 -> 'number' -> ToNumber('number') -> NaN");

var s = "2";
var n = 2;

assert.sameValue(2 ** +s, 4, "+s -> +'2' -> 2 -> ToNumber(2) -> 2");
assert.sameValue(2 ** +n, 4, "+s -> +2 -> 2 -> ToNumber(2) -> 2");

assert.sameValue(2 ** -s, 0.25, "-s -> -'2' -> -2 -> ToNumber(-2) -> -2");
assert.sameValue(2 ** -n, 0.25, "-s -> -2 -> -2 -> ToNumber(-2) -> -2");

assert.sameValue(2 ** ~s, 0.125, "~s -> ~'2' -> -3 -> ToNumber(-3) -> -3");
assert.sameValue(2 ** ~n, 0.125, "~s -> ~2 -> -3 -> ToNumber(-3) -> -3");

assert.sameValue(2 ** !s, 1, "!s -> !'2' -> false -> ToNumber(false) -> 0");
assert.sameValue(2 ** !n, 1, "!s -> !2 -> false -> ToNumber(false) -> 0");


var capture = [];
var leftValue = { valueOf() { capture.push("leftValue"); return 3; }};
var rightValue = { valueOf() { capture.push("rightValue"); return 2; }};

(capture.push("left"), leftValue) ** +(capture.push("right"), rightValue);
//                                   ^
//                            Changes the order

// Expected per operator evaluation order: "left", "right", "rightValue", "leftValue"
assert.sameValue(capture[0], "left", "Expected the 1st element captured to be 'left'");
assert.sameValue(capture[1], "right", "Expected the 2nd element captured to be 'right'");
assert.sameValue(capture[2], "rightValue", "Expected the 3rd element captured to be 'rightValue'");
assert.sameValue(capture[3], "leftValue", "Expected the 4th element captured to be 'leftValue'");