ES6 Deep Dive

A deep dive into three features of ECMAScript Edition 6: symbols, structs, and generators.

Transcript

1. Dave Herman ES6 Deep Dive Symbols, Structs, Generators
3. About me • @littlecalculist • http://calculist.org • http://github.com/dherman • Mozilla Research • TC39 • Also…
4. In print this December http://effectivejs.com
5. Symbols
6. JS property names are strings var obj = { foo: 42 }; obj["foo"]; // 42
7. The all-powerful _ character function Dict() { this._entries = {}; } Don’t touch me, I’m private!
8. When you mean business… __proto__ private SO PRIVATE REALLY GUYS SOOO TOTALLY PRIVATE private!
9. Conventions are no guarantee function SuperClass() { this._data = "superclass private data"; } function SubClass() { SuperClass.call(this); this._data = "subclass private data"; // collision! } SubClass.prototype = Object.create(SuperClass.prototype);
10. Closures for information hiding function SuperClass() { var data = "private data"; this.method = function() { /* ... */ data /* ... */ }; } no sharing: one method per instance!
11. Introducing symbols
12. Introducing symbols var sym = new Symbol("data");
13. Introducing symbols var sym = new Symbol("data"); function SuperClass() { this[sym] = "private data"; }
14. Introducing symbols var sym = new Symbol("data"); function SuperClass() { this[sym] = "private data"; } SuperClass.prototype.method = function() { /* ... */ this[sym] /* ... */ };
15. Introducing symbols var obj = new SuperClass(); "data" in obj; // false "_data" in obj; // false sym in obj; // true
16. Performance • Engines already do string interning • Convertible to a fixed offset with inline caches
17. Proposal: scoped symbols private @sym; function SuperClass() { this.@sym = "private data"; } SuperClass.prototype.method = function() { /* ... */ this.@sym /* ... */ };
18. Structured binary data
19. Typed arrays var a = new Uint32Array(1024); a[17] = 42;
20. Typed arrays var vertices = new Float32Array([ -1.0, -1.0, 0.0, // vertex 1 0.0, 1.0, 0.0, // vertex 2 1.0, -1.0, 0.0 // vertex 3 ]); -1.0 -1.0 0.0 0.0 1.0 0.0 1.0 -1.0 0.0 0 4 8 12 16 20 24 28 32
21. Structs var Point = struct({ x: float32, y: float32, z: float32 }); var origin = new Point(0.0, 0.0, 0.0); origin.x; // 0.0 origin.y; // 0.0
22. Arrays of structs var vertices = new Point.array([ { x: -1.0, y: -1.0, z: 0.0 }, { x: 0.0, y: 1.0, z: 0.0 }, { x: 1.0, y: -1.0, z: 0.0 } ]); -1.0 -1.0 0.0 0.0 1.0 0.0 1.0 -1.0 0.0 0 4 8 12 16 20 24 28 32
23. JIT compilers — types
24. Applications of structs • WebGL data • File and network I/O • Compiling other languages to JS
25. Generators
26. Lies, lies, lies “JS doesn’t have concurrency.” “JS is single-threaded so it can’t have race conditions.” “Event-based programming is easy.”
27. Download three files load("foo", function(foo) { load("bar", function(bar) { // why wait? load("baz", function(baz) { use([foo, bar, baz]); }); }); });
28. Download three files load("foo", function(foo) { load("bar", function(bar) { // why wait? load("baz", function(baz) { use([foo, bar, baz]); }); }); });
29. Download three files var files = []; ["foo", "bar", "baz"].forEach(function(url, i) { load(url, function(file) { files.push(file); // no! if (i === 3) // no! use(files); }); });
30. Download three files var files = []; ["foo", "bar", "baz"].forEach(function(url, i) { load(url, function(file) { files[i] = file; if (files.length === 3) // still no! use(files); }); });
31. Download three files var files = [], count = 0; ["foo", "bar", "baz"].forEach(function(url, i) { load(url, function(file) { files[i] = file; if (++count === 3) use(files); }); });
32. JavaScript is concurrent Cooperative concurrency: easier, but not easy! Handlers run sequentially but start concurrently. Shared state 㱺 race conditions 㱺 pain and suffering
33. task.js: Beautiful concurrency spawn(function*() { var files = yield join(load("foo"), load("bar"), load("baz")); use(files); }); http://taskjs.org
34. task.js: Beautiful concurrency spawn(function*() { var files = yield join(load("foo"), load("bar"), load("baz")); use(files); }); create a task that can be paused pause! http://taskjs.org
35. Generator functions function* evenNumbers() { for (var next = 0; true; next += 2) { yield next; } }
36. Generator functions function* evenNumbers() { for (var next = 0; true; next += 2) { yield next; } }
37. Generator functions function* evenNumbers() { for (var next = 0; true; next += 2) { yield next; } } evenNumbers(); ✗
38. Generator functions function* evenNumbers() { for (var next = 0; true; next += 2) { yield next; } } evenNumbers(); ✗
39. Generators function* f() { }
40. Generators function* f() { } .next: var g = f(); ⋮
41. Generators function* evenNumbers() { /* ... */ } var g = evenNumbers(); g.next(); // 0 g.next(); // 2 g.next(); // 4 starts out paused
42. Lazy iteration Dict.prototype.keys = function*() { for (var key in this._entries) yield key; };
43. Iterators work with for-of var dict = new Dict(); // ... for (var key of dict.keys()) { console.log(key + ": " + dict.get(key)); }
44. Pausing is powerful load("config.json", function(config) { db.lookup(JSON.parse(config).table, username, function(user) { load(user.id + ".png", function(avatar) { // ... }); }); });
45. Pausing is powerful load("config.json", function(config) { db.lookup(JSON.parse(config).table, username, function(user) { load(user.id + ".png", function(avatar) { // ... }); }); }); later later later
46. Pausing is powerful load("config.json", function(config) { db.lookup(JSON.parse(config).table, username, function(user) { load(user.id + ".png", function(avatar) { // ... }); }); }); later later later
47. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
48. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
49. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
50. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
51. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
52. Pausing with promises load("config.json") .then(function(config) { return db.lookup(JSON.parse(config).table); }) .then(function(user) { return load(user.id + ".png"); }) .then(function(avatar) { /* ... */ });
53. Tasks yield promises spawn(function*() { var config = JSON.parse(yield load("config.json")); var user = yield db.lookup(config.table, username); var avatar = yield load(user.id + ".png"); // ... });
54. Tasks yield promises spawn(function*() { var config = JSON.parse(yield load("config.json")); var user = yield db.lookup(config.table, username); var avatar = yield load(user.id + ".png"); // ... });
55. Tasks yield promises spawn(function*() { var config = JSON.parse(yield load("config.json")); var user = yield db.lookup(config.table, username); var avatar = yield load(user.id + ".png"); // ... }); looks like a synchronous API!
56. What about errors? load("foo", function(foo) { load("bar", function(bar) { load("baz", function(baz) { use([foo, bar, baz]); }, function(err) { /* ... */ }); }, function(err) { /* ... */ }); }, function(err) { /* ... */ });
57. What about errors? load("foo", function(err, foo) { if (err) return onError(err); load("bar", function(err, bar) { if (err) return onError(err); load("baz", function(err, baz) { if (err) return onError(err); use([foo, bar, baz]); }); }); });
58. Error handling with promises var p = load("config.json") .then(function(config) { /* ... */ } .then(function(user) { /* ... */ }) .then(function(avatar) { /* ... */ }); when(p, function(result) { /* ... */ }, function(err) { /* ... */ });
59. Error handling with tasks spawn(function*() { try { var config = JSON.parse(yield load("config.json")); var user = yield db.lookup(config.table, username); var avatar = yield load(user.id + ".png"); // ... } catch (e) { /* ... */ } });
60. Wait for multiple events spawn(function*() { var [foo, bar, baz] = yield join(load("foo"), load("bar"), load("baz")); // ... });
61. Purposefully race events spawn(function*() { try { var foo = yield select(load("foo"), timeout(3000)); // ... } catch (e) { /* timed out */ } });
62. Generators • Interruptible computations 㱺 custom iterators • Pausing with yield 㱺 concurrency minus the callbacks
63. Something completely different
64. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]
65. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]
66. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "[object Object]"
67. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "[object Object]"
68. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "[object Object]" true true true
69. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "[object Object]" 3
70. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "j"
71. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "false" "j"
72. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "false" 3 "j"
73. ({}+[])[!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]] "j" "s"
74. ! + { } [ ] ( ) \n === JavaScript
75. Um. So… why?
76. • No reason. Um. So… why?
77. • Yosuke Hasegawa: JSF*ck • Patricio Palladino: Hieroglyphy • Me: pure JS, no browser API’s Not the first deranged weirdo
78. > String+[] "function String() { [native code] }" "S"
79. > "".constructor+[] "function String() { [native code] }" "S"
80. > ""["constructor"]+[] "function String() { [native code] }" "S"
81. > [].slice.call(""["constructor"]+[]) ["f","u","n","c","t","i","o","n"," ","S","t","r", /* ... */] "S"
82. > [].slice.call(""["constructor"]+[]) [" ","f","u","n","c","t","i","o","n"," ","S","t","r", /* ... */] "S"
83. > function nonWhitespace(s) { return !/^\s*$/.test(s) } > [].slice.call(""["constructor"]+[]).filter(nonWhitespace) ["f","u","n","c","t","i","o","n","S","t","r", /* ... */] "S"
84. > Number("f") NaN > Number(" ") 0 > isNaN("f") true > isNaN(" ") false "S"
85. > [].slice.call(""["constructor"]+[]).filter(isNaN) ["f","u","n","c","t","i","o","n","S","t","r", /* ... */] "S"
86. > [].slice.call(""["constructor"]+[]) .filter(Function("return isNaN")()) ["f","u","n","c","t","i","o","n","S","t","r", /* ... */] "S"
87. > [].slice.call(""["constructor"]+[]) .filter(Array.constructor("return isNaN")()) ["f","u","n","c","t","i","o","n","S","t","r", /* ... */] "S"
88. > [].slice.call(""["constructor"]+[]) .filter([].constructor.constructor("return isNaN")()) ["f","u","n","c","t","i","o","n","S","t","r", /* ... */] "S"
89. > [].slice.call(""["constructor"]+[]) .filter([].constructor.constructor("return isNaN")())[8] "S" "S"
90. > (9).toString() "9" > (15).toString(16) "f" > (16).toString(17) "g" "p"
91. > (25).toString(26) "p" "p"
92. > (25)["toString"](26) "p" "p"
93. > escape(" ") "%20" "%"
94. > Function("return escape")()(" ") "%20" "%"
95. > Function("return escape")()(" ")[0] "%" "%"
96. > Function("return unescape")()("%3b") ";" Any ASCII character
97. > (({}+[])[!![]+!![]+!![]]+[]+(![]+[])[+!![]]+(+(!![]+!![]+!![]+[]+ (+!![])))[(!![]+[])[+![]]+[]+({}+[])[+!![]]+[][(![]+[])[!![]+!![] +!![]]+[]+(![]+[])[!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!! []]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]] [({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+(![]+[])[+!![]]+(![]+[])[!![] +!![]]+(![]+[])[!![]+!![]]](+[![]]+[]+(!![]+[])[({}+[])[!![]+!![] +!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!! []+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+ ({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+ (!![]+[])[+!![]]])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!! []+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!! []]+(!![]+[])[+!![]]]([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+ [])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[]) [+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![] +!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+ [])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]] +(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]] +[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+ [])[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!! []+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][!
98. []]+[])[+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]] +[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]])) ())[+(+!![]+[]+(+!![]))]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+ [])[!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[+!![]]+[][(![]+[])[!![] +!![]+!![]]+[]+(![]+[])[!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![] +!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]] [({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+(![]+[])[+!![]]+(![]+[])[!![] +!![]]+(![]+[])[!![]+!![]]]((!![]+[])[({}+[])[!![]+!![]+!![]+!![] +!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!! []]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!! []+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[]) [+!![]]]+[])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!![]+!! []]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!![]]+ (!![]+[])[+!![]]]([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[]) [+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+! []]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![] +!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+[])[!! []+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+ [])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[]) [+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[]) [+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!![
99. ]+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][! []]+[])[+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]] +[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]])) ())[+(+!![]+[]+(!![]+!![]+!![]))]](+(!![]+!![]+!![]+[]+(!![]+!! [])))+(![]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+({}+[])[!![]+!![]+!! []+!![]+!![]]+(!![]+[])[+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!! []]+(+(!![]+!![]+[]+(!![]+!![]+!![]+!![]+!![])))[(!![]+[])[+![]]+[] +({}+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+[])[!![]+!![]]+ ([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![] +!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]] +[]+(![]+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]](+[![]] +[]+(!![]+[])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+ ([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+ [])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!! []+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]])[(![]+[])[+![]]+[]+ ([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+ [])[+![]]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+!![]]]([][({}+[])[!! []+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+ [])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[]) [+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[]) [+!![]]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+
100. [])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[]) [+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![] +!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]]((!![]+ [])[+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+ [])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+!![]]+({}+[])[!![]+!![]+!! []+!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![] +[])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+(+!![]))]+(!![]+[])[+! []]+(!![]+[])[+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+([][! []]+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+[])[!![]+!![]]+ ([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![] +!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]] +[]+(![]+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]]((!![]+ [])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+ [])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!! []]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[]) [+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]]+[])[(![]+[])[+![]]+[]+([][! []]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+! []]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+!![]]]([][({}+[])[!![]+!! []+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[]) [!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+! []]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!!
101. []]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[]) [+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+! []]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![] +!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]]((!![]+[]) [+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+[]) [+![]]+(!![]+[])[+!![]]+([][![]]+[])[+!![]]+({}+[])[!![]+!![]+!![] +!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+ [])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+(!![]+!![]+!![]))]](+ (!![]+!![]+!![]+[]+(+![])))+(!![]+[])[+![]]) "javascript"
102. (({}+[])[!![]+!![]+!![]]+[]+(![]+[])[+!![]]+(+(!![]+!![]+!![]+[]+(+!![])))[(!![]+[])[+![]]+[]+({}+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+ [])[!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!! []]+[]+(![]+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]](+[![]]+[]+(!![]+[])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+ [])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[]) [+!![]]+(!![]+[])[+!![]]])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!![]]+ (!![]+[])[+!![]]]([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!! []]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+ [])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![] +[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][! []]+[])[+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+ (+!![]))]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+[])[!![] +!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+(! []+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]]((!![]+[])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[]) [!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!! []]]+[])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+!![]]] ([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[]) [+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][! []]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+ [])[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+!![]]+ ({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+(!![]+!![]+!! []))]](+(!![]+!![]+!![]+[]+(!![]+!![])))+(![]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+!![]]+([][![]]+[]) [!![]+!![]+!![]+!![]+!![]]+(+(!![]+!![]+[]+(!![]+!![]+!![]+!![]+!![])))[(!![]+[])[+![]]+[]+({}+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+[]) [!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+ []+(![]+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]](+[![]]+[]+(!![]+[])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[]) [+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!! []]+(!![]+[])[+!![]]])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!![]]+(!![] +[])[+!![]]]([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+ ([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[]) [+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+ [])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][! []]+[])[+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+ (+!![]))]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[+!![]]+[][(![]+[])[!![]+!![]+!![]]+[]+(![]+[])[!![] +!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[!![]+!![]+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+(! []+[])[+!![]]+(![]+[])[!![]+!![]]+(![]+[])[!![]+!![]]]((!![]+[])[({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[]) [!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!! []]]+[])[(![]+[])[+![]]+[]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+!![]]] ([][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][![]]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[]) [+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+[])[+!![]]+(!![]+[])[+!![]]][({}+[])[!![]+!![]+!![]+!![]+!![]]+[]+({}+[])[+!![]]+([][! []]+[])[+!![]]+(![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+![]]+({}+[])[!![]+!![]+!![]+!![]+!![]]+(!![]+[])[+![]]+({}+ [])[+!![]]+(!![]+[])[+!![]]]((!![]+[])[+!![]]+[]+(!![]+[])[!![]+!![]+!![]]+(!![]+[])[+![]]+([][![]]+[])[+![]]+(!![]+[])[+!![]]+([][![]]+[])[+!![]]+ ({}+[])[!![]+!![]+!![]+!![]+!![]+!![]+!![]]+([][![]]+[])[!![]+!![]+!![]+!![]+!![]]+(![]+[])[!![]+!![]+!![]]+(+[![]]))())[+(+!![]+[]+(!![]+!![]+!! []))]](+(!![]+!![]+!![]+[]+(+![])))+(!![]+[])[+![]])