Brainfuck beware: JavaScript is after you (2012) • Hacker News Board

Re: Brainfuck beware: JavaScript is after you (2012)

#11

Post by lawl » Mon, Jun 02, 2014, 5:14 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

I'd say both. But it does matter. It could for example be used in obfuscators. Brainfuck itself has formal proof of being turing complete, so the easiest way today to prove that a language is turing complete is to implement a brainfuck interpreter. Which is just a few lines of code instead of this: http://www.iwriteiam.nl/Ha_bf_Turing.html

Re: Brainfuck beware: JavaScript is after you (2012)

#12

Post by icambron » Mon, Jun 02, 2014, 5:23 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

Waiving aside the practical applications for a second, remember that this is an art to us. We have a canvas and a set of paints, and we make stuff out of it. Exploring the limits of that medium is part of the fun, but also part of understanding our art. What are the consequences of this? How far can this envelope be pushed?

There was a guy who wrote an entire novel that never used the letter "e" [1]. Is that showing off? Maybe, I guess. It's also a really interesting exercise in writing.

[1] https://en.wikipedia.org/wiki/Gadsby_(novel)

Re: Brainfuck beware: JavaScript is after you (2012)

#13

Post by gioele » Mon, Jun 02, 2014, 5:27 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

«It is hard to write a simple definition of something as varied as hacking, but I think what these activities have in common is playfulness, cleverness, and exploration. Thus, hacking means exploring the limits of what is possible, in a spirit of playful cleverness. Activities that display playful cleverness have "hack value".»

https://stallman.org/articles/on-hacking.html

«The MIT group defined a hack as a project undertaken or a product built to fulfill some constructive goal, but also with some wild pleasure taken in mere involvement.»

http://en.wikipedia.org/wiki/Hacker_ethic

Re: Brainfuck beware: JavaScript is after you (2012)

#14

Post by adr_ » Mon, Jun 02, 2014, 5:29 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

It is a fun mental exercise. I love this stuff, and that's the motivation.

I once wrote an emulator for a 4 bit microprocessor in Befunge (a 2D esoteric programming language). Then, I was definitely showing off something that really does not matter. 100% useless.

This is a little different. The motivation is the same, but it also proves that you cannot sanitise Javascript by removing letters or words. It's very easy to assume that such sanitisation works, and such an assumption can be a security-critical mistake. I've actually read this article before because I needed to solve such a problem.

Re: Brainfuck beware: JavaScript is after you (2012)

#15

Post by anonymoushn » Mon, Jun 02, 2014, 5:31 AM UTC

Pitarou wrote: post #7

Yet another example of the horrible mess unprincipled automatic type conversion causes. What prevents language designers from avoiding all these lurking bugs with a generic type-conversion operator? E.g. here's how it might look in a Python-like language: >>> x = 1 >>> y = "2" >>> print(x + cast(y)) 3 >>> print(cast(x) + y) "12" >>> print(cast(x) + cast(y)) Exception: ambiguous type

Why is this preferable to a set of functions that return a particular type? Most uses of such a cast function would be something like

  cast(unknown_type)  known_type

The programmer could just write tostring or tonumber instead of cast, if the type of the other operand is known >_>

Re: Brainfuck beware: JavaScript is after you (2012)

#16

Post by NAFV_P » Mon, Jun 02, 2014, 5:32 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

One of the original aims of the Brainfuck language was to implement an interpreter that had a tiny memory footprint (one Brainfuck interpreter took up 186 bytes of memory). This has been a big concern among programmers for decades, although not so relevant these days.

Apparently BCPL [0], which dates back to 1966, had a compiler that took up 16k of RAM, some bootstrapped. BCPL influenced B [1], B influenced C [2].

[0] http://en.wikipedia.org/wiki/BCPL [1] http://en.wikipedia.org/wiki/B_(programming_language) [2] http://en.wikipedia.org/wiki/C_(programming_language)

Re: Brainfuck beware: JavaScript is after you (2012)

#17

Post by alcuadrado » Mon, Jun 02, 2014, 5:49 AM UTC

nirmel wrote: post #8

I am not a programmer so this is part curiosity and part criticism. Why do programmers seem to enjoy creating programs that satisfy some syntactical constraint? Is it a fun mental exercise, or or can you just admit that you're showing off on something that really does not matter?

The author here: as mentioned in the article, it started as part of a security research, but once started I couldn't help myself from pushing it further and see how far I could get. So I guess it's curiosity and a fun mental exercise, and maybe probing yourself that you can do something that you thought was impossible.

Re: Brainfuck beware: JavaScript is after you (2012)

#18

Post by alcuadrado » Mon, Jun 02, 2014, 5:52 AM UTC

zatkin wrote: post #6

I'm curious on what the performance implications are. If I have some JavaScript on a webpage that I want to "obfuscate", would using this accomplish the task?

The performance seriously decreases. I haven't measure how much, but I guess it'd only work for very very small scripts.

Re: Brainfuck beware: JavaScript is after you (2012)

#19

Post by Noctem » Mon, Jun 02, 2014, 5:53 AM UTC

It's been a while since I last brushed up on the Geneva Conventions, but I think this violates most of them.

Re: Brainfuck beware: JavaScript is after you (2012)

#20

Post by SixSigma » Mon, Jun 02, 2014, 6:39 AM UTC

Pitarou wrote: post #7

Yet another example of the horrible mess unprincipled automatic type conversion causes. What prevents language designers from avoiding all these lurking bugs with a generic type-conversion operator? E.g. here's how it might look in a Python-like language: >>> x = 1 >>> y = "2" >>> print(x + cast(y)) 3 >>> print(cast(x) + y) "12" >>> print(cast(x) + cast(y)) Exception: ambiguous type

How about something like this

    >>> print(str(x) + y)
    "12"
    >>> print(x + int(y))
    3
    >>> print (x+y)
    Traceback (most recent call last):
      File "", line 1, in 
    TypeError: unsupported operand type(s) for +: 'int' and 'str'

That's already Python