Wat

http://www.destroyallsoftware.com/talks/wat

by abahgat • 14 years ago

512 98 14 years ago

destroyallsoftware.com

chetan51• 14 years ago

WAT

Karunamon• 14 years ago

Wat.

liquidchaz• 14 years ago

Wat?

angli• 14 years ago

This is incredibly funny, but does anyone know why the interpreter makes such bizarre decisions? Why wouldn't it be preferable to just throw up errors?

Tashtego• 14 years ago

Welcome to the world of JavaScript. This response is NaN.

ajross• 14 years ago

Javascript was a rush job. And the ECMA spec was needed early due to industry pressure. So where perl and (to a lesser extent) python were able to just bury their early goofs in a pile of incompatible versions bumps, Javascript had its encased in the proverbial carbonite of an international standard. Which is sad, really, because in a lot of other ways it's the cleanest scripting language of its generation.

getsat• 14 years ago

For more sadness, see: http://wtfjs.com

Fun fact: the creator of Javascript posts on HN. Maybe he'll answer your question.

tzs• 14 years ago

The Ruby stuff apparently isn't bizarre. From what I've read, Ruby creates variables as it encounters an assignment to them when parsing the code. So, when you have

   a = a

in your code, Ruby creates the variable a before it ever tries to actually execute the assignment. If later, when it has finished parsing everything, and starts executing, that statement fails because b is not defined, you still end up with variable a being defined, and since it has not had anything successfully assigned to it, it has a value of nil.

The JavaScript stuff, I think, comes from operator overloading. The plus operator is overloaded to allow adding strings to concatenate them, and it will do type conversion to get compatible types, so "wat"+1 results in the 1 being converted to a string, and then the strings are concatenated. Since the minus operator is not so overloaded, "wat"-1 instead is treated as numerical subtraction. JavaScript allows string to be used as numbers, so "123"-1 gives 122. However "wat" is not a string that represents a number, so gives NaN when forced to be treated as a number, and "wat"-1 is thus NaN.

lucisferre2• 14 years ago

Thanks for that. I was curious the reason, it seems obvious though after an explanation.

lmkg• 14 years ago

JavaScript has a strong design principle of not throwing errors for syntactically valid constructs. The most common way it accomplishes this is through gratuitous use of implicit type conversions. It does a lot of implicit string conversions, even on things that you would think of as error codes, like undefined or NaN.

JavaScript went down the path of being a "forgiving" language because it was intended to provide "extra" (non-core) functionality, under a lot of environments, in the hands of non-experts. It made sense at the time that it should fail silently rather than noisily to not crash the page it was on. It also tried to help amateurs who just banged on code until it did what they wanted, by generally doing something rather than nothing, and by trying to infer intended behavior from undisciplined code. It was never intended to make large-scale or robust applications, so it didn't make decisions that would facilitate that use-case.

runT1ME• 14 years ago

I wish there was some technology that could take a bunch of code and warn you of common errors before having it execute and 'noisily crash the page it was on'.

Maybe someday...

qqqqqq• 14 years ago

Hilarious! This reminds me of a StackOverflow question which asked the users for the weirdest language quirks they could think of. I laughed pretty hard at that too.

franciscoapinto• 14 years ago

This is a repost, but whatever. Hopefully people who haven't seen it before will enjoy it.

libraryatnight• 14 years ago

Even with my limited programming knowledge I laughed a lot through this.

felideon• 14 years ago

At work people always tell me "You IT guys are all so funny."

murphysbooks• 14 years ago

I laughed so loud I scared myself. Now, I know why my wife looks at me funny.

stevenou3• 14 years ago

Wow, I laughed so hard I cried! This is hilarious...

nekomata• 14 years ago

wow, you must be the best hacker ever congrats

stevenou3• 14 years ago

I understand the downvotes since this is HN and you people don't like useless comments here. But I simply thought it was very funny. No need to be mean here.

hchinchilla2• 14 years ago

Does anybody knows which is the javascript interpreter he is using on the screencast?

jarito• 14 years ago

Looks like something that comes as part of Webkit:

http://trac.webkit.org/wiki/JSC

GuiA• 14 years ago

It's jsc (comes with Webkit) - it's present on Mac OS X by default in

/System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc

You can just do:

sudo ln /System/Library/Frameworks/JavaScriptCore.framework/Versions/A/Resources/jsc /bin/jsc

To be able to invoke it directly from the command line.

hchinchilla2• 14 years ago

Thanks, I'll look how to get this working on linux.

bitops• 14 years ago

That is extremely useful. Do you know if any testing libraries or other useful functionality have been built around this?

I suppose if you are a WebKit-only developer, this utility could have many useful applications.

phuff• 14 years ago

<shamelessplug>If you want to use any of these inside emacs check out my js-comint mode: http://js-comint-el.sourceforge.net/ Makes it really easy to do things like write code in one buffer and execute it in another. </shamelessplug>

greenpizza13• 14 years ago

This is hilarious!

brudgers• 14 years ago

Quicktime? We don't need no stinking web standards!

program• 14 years ago

   $ php -r '::'
   Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM

Wat

dangrossman• 14 years ago

Pffth, you just need to learn Hebrew before you learn PHP. That says "double dot twice".

eridius• 14 years ago

  $ php -r '::'
  Parse error: parse error in Command line code on line 1

How'd you get the weird error?

Edit:

Hrm, if I try it on my DreamHost account, I get something more similar to yours:

  $ php -r '::'
  Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM in Command line code on line 1

chrisrogers• 14 years ago

This was introduced by Zend, which is israeli. Thus the Hebrew.

jfarmer• 14 years ago

I first saw that error in a pre-Google world. It took a few days for me to figure out what it meant.

overshard• 14 years ago

This is the greatest video ever.

tylerritchie2• 14 years ago

What presentation software is he using? Is he just jumping from his slide deck into a shell?

garybernhardt6• 14 years ago

It's Keynote. I recorded those sessions as screencasts, then sliced them into tiny pieces so I can advance them perfectly with my talking. There are 37 slides in that four-minute talk. In some cases, the slices are only two or three frames long.

tylerritchie2• 14 years ago

Ah that makes sense, thank you. I may steal that idea for future talks with R. Though, just embedding a shell in a slide deck would be very nice.

flatline2• 14 years ago

Guess I'm not a hacker? It's like watching a rerun I've seen twice over with the laugh track turned up to 11 (just to clarify, someone said it was a repost but I haven't seen it before).

garybernhardt6• 14 years ago

There's no laugh track; that's the audience.

dmansen2• 14 years ago

Yeah count me in the "not a hacker, I guess" crowd, this stuff isn't very funny.

Zancarius3• 14 years ago

"Wat" at the start really turned me off. I realize that was probably (?) part of the shtick, but it's one misspelling in particular that really drives me nuts. Real hacker humor is fairly dry (the story about magic comes to mind); this felt more like script kiddie-level humor. I can see valid points (and humor) raised with the Ruby interpreter, but the delivery could have been better--at least more adult-ish.

I managed about halfway through. I did have the audio turned off, so I'm assuming I missed out on some of the redeeming qualities it may have had. Given the liberal usage of "wat" throughout what I did watch, I suspect that my gut feel is likely correct.

billpatrianakos3• 14 years ago

Right. It was marginally informative, the meme pics were chuckle-in-my-head worthy but what really got me laughing was that it's on the front page of HN. Its so sad you have to laugh to keep from crying.

Anyway, guess I'm not a hacker either.

jh3• 14 years ago

Really? You don't think this is funny at all? Maybe it's because I'm in my mid twenties, but I think my father would even find this funny and he knows little to none about programming.

bphogan• 14 years ago

My (non programmer) wife found this hysterical. It reinforced her belief that programming is stupid. :)

dmansen2• 14 years ago

If there were jokes formed around the nonsensical behavior of these languages, then it might be funny. But I don't find it very entertaining to just point them out.

flatline2• 14 years ago

The humor is playing on an inclination to laugh at things we don't understand, which seems counter to the hacker ethos. Software is hard, and there may be deep reasons in the dynamic type systems that cause these languages to work like this, or there may not be, but either way this type of thing is interesting and seems to demand some further explanation and/or justification. I find it interesting but don't get the humor. Perhaps, as you implied, I'm just too old.

tlrobinson2• 14 years ago

I didn't laugh because I was so worried that if I didn't laugh I wouldn't be considered a hacker :(

firefoxman1• 14 years ago

I didn't laugh until the end. Partially, I'm sure, because I didn't want to lie to myself by intentionally laughing just to feel like a hacker. But when I saw NaNNaNNaNNaN...(etc) coming, I couldn't help it.

bfrs• 14 years ago

Your comment made me laugh a lot! Thanks.

nodesocket• 14 years ago

Interestingly the results from jsc, are different from node.js:

----- jsc ------

   [] + []
   
   > [] + {}
   [object Object]
   > {} + []
   0
   > {} + {}
   NaN

------ node.js ------

   > [] + []
   ''
   > [] + {}
   '[object Object]'
   > {} + []
   '[object Object]'
   > {} + {}
   '[object Object][object Object]'

lftl• 14 years ago

I don't even understand what the last node.js entry is. Is that an array with two objects?

Also, I'm on an old version of node, but my output matches jsc.

udp• 14 years ago

The `toString` of two Object-s concatenated, I think.

esrauch• 14 years ago

The other reply is right, to clarify String({}) === "[object Object]"

I think the actual video was a little misleading, [] + {} == the string "[object Object]" not an object. The square brackets are just part of the tostring method and are unrelated to the square brackets of arrays.

Cushman3• 14 years ago

This appears to be a peculiarity of the REPL implementations, not a difference between V8 and JSC. d8 (and the Chrome console) behaves the same way as jsc, while you can make d8 and jsc behave the same as the node REPL by wrapping each statement in parentheses:

  d8> ([] + [])
  
  d8> ([] + {})
  [object Object]
  d8> ({} + [])
  [object Object]
  d8> ({} + {})
  [object Object][object Object]

So I believe this is merely erroneous behavior of the console, not a weirdness of JavaScript itself.

garybernhardt6• 14 years ago

No, it's more subtle than that. By wrapping in parenthesis, you're making it an expression. When you just say "{}+[]" in e.g. Chrome, the first {} is parsed as a block. So what you see printed is the result of "+[]", which is 0. This is why {}+[] is not equal to {}+[] without parens. This may also be why Node gives different results; I'm not sure.

I didn't mention any of this in the talk (it would've killed the flow ;). Instead, I glossed over it and interpreted the syntax as any sane programmer would.

nabilt• 14 years ago

The presenter also has a catalog of screencasts here https://www.destroyallsoftware.com/screencasts. Haven't listen to them, but the topics look interesting.

eggbrain• 14 years ago

Wow, this title suffers from some serious editorializing. What's next, "10 ways to know if you are a hacker? (cracked.com)"

famousactress• 14 years ago

I feel like we've been suffering extra-much from this effect lately...

baddox• 14 years ago

How does this have anything to do with a sense of humor specific to hackers? Don't all professionals enjoy jokes about their field?

abahgat• 14 years ago

That is exactly what I was wondering: what you say must be true, but I could not find any equivalent of what you see here for any other profession.

But maybe it is just because I write code for a living...

bgarbiak• 14 years ago

What's the "correct" ("less funny"?) result of

   Array(16).join("wat" - 1) + " Batman!"

Empty strings separated with NaNs look perfectly logical to me (I'm a JS guy though, so, well, bear with me).

Anderkent• 14 years ago

A TypeError.

weavejester• 14 years ago

That's probably one of the more logical examples. I'd have expected an exception from any other language, though (Javascript I know doesn't tend to type error).

antoncohen• 14 years ago

Well, .join(x) joins an array into a string, with x as the separator. First of all what does Array(16) make? Effectively it should make an array with null 16 times. Now, JavaScript seems to think null is a blank string, a string with the text 'null', or a zero depending on the context.

The first thing it should do is TypeError that null is not a string. Or don't join null fields because there is nothing there.

If is does convert null to '', then it should TypeError on string - int. If it is not going to TypeError it should do something sensible, like slice the string

  > Array(16).join("wat".slice(0,-1)) + " Batman!"
  'wawawawawawawawawawawawawawawa Batman!'

I think the correct thing would be to TypeError in two different places. Or change the language so things that don't error actually work. Returning a string with NaNs in it will just lead to uncaught errors. If it actually returns something it should probably be ' Batman!'.

JavaScript nuttiness:

Now it's zero:

  > null + 1
  1

Now it's "null":

  > null + "text"
  'nulltext'

Now it's a blank string:

  > [null, null, null].join()
  ',,'

Python errors when things don't make sense, and forces you to make them make sense:

If it doesn't work, error:

  >>> "wat" - 1
  Traceback (most recent call last):
	  File "<stdin>", line 1, in <module>
  TypeError: unsupported operand type(s) for -: 'str' and 'int'

Can't join None into a string:

  >>> ','.join([None, None, None])
  Traceback (most recent call last):
	  File "<stdin>", line 1, in <module>
  TypeError: sequence item 0: expected string, NoneType found

Convert None to a string if you want:

  >>> ','.join([str(i) for i in [None, None, None]])
  'None,None,None'

But it makes more sense to drop the None:

  >>> ','.join([str(i) for i in [None, None, None] if i])
  ''

orbitingpluto• 14 years ago

Array(16)

That's 15 commas, not 16.

tlrobinson2• 14 years ago

Handy way to make some padding:

    function pad(n, c) { return Array(n+1).join(c); }

    // pad(6, "-") === "------"

baby• 14 years ago

if you laugh, you know ruby.

iapetos• 14 years ago

why do i have to signup to know who much it costs to subscribe. I think it should be apparent on the home page.

EDIT ok my bad it was mentioned on the screencasts homepage

garybernhardt6• 14 years ago

It's on the front page, but at the bottom. DAS is a small one-man business, so I did the design myself (and I'm not a good designer). Sorry about that. :)

jrockway4• 14 years ago

I guess you had to be there. I can see why someone might find this funny, but honestly, nothing is that funny. Some behavior in Javascript is surprising, but not that surprising.

marshray• 14 years ago

If you've ever gone through a phase (or a graduate degree!) of thinking deeply about programming language design, you might, as I do, find Javascript's expression evaluation behavior to be just about the funniest thing around.

jrockway4• 14 years ago

I have but I don't. Javascript was designed to reduce programmer-visible errors at the cost of making it nearly impossible to write a correct program. At that goal, it succeeds, and [] + {} being NaN makes perfect sense under those constraints.

there• 14 years ago

that weird behavior of javascript can actually be used for xss attacks, by being able to assemble strings. for example:

   (![]+[])[+!+[]]

produces an "a".

https://news.ycombinator.com/item?id=1153383

jrockway4• 14 years ago

But of course, anyone that actually wants to protect against XSS attacks won't allow user input to be evaluated. If they did want to allow user-supplied Javascript, they wouldn't blacklist, they would whitelist (by parsing the user-supplied script and using the AST to emit only whitelisted operations).

glhaynes• 14 years ago

Have I been pronouncing "wat" wrong all this time? I just assumed it was like "what" but ... not.

gnarbarian• 14 years ago

No. I'm with you man. The way he said it was seriously bugging me. At the same time I couldn't justify my annoyance with an alternative pronunciation that made sense.

Perhaps some memes should never be vocalized.

farnsworth• 14 years ago

I guess this is where we all complain about HN finally jumping the shark and turning into Reddit.

conbtl• 14 years ago

Congrats to all of you who laughed. You are all great hackers. I don't find this remotely funny.

nessus42• 14 years ago

I think that a hacker would also realize that the title makes no claim whatsoever about the hacker status of those who don't laugh.

phzbOx• 14 years ago

For some reason, what I find the most hilarious here is reading the extremely serious HN comments. It's a weird contrast.

Wat

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