The long arrow operator in C++

http://cukic.co/2017/07/12/the-long-arrow-operator-in-cxx/

by santaclaus • 9 years ago

177 59 9 years ago

cukic.co

pzone• 9 years ago

Cute. Though if I actually saw this in a codebase I might tear my hair out.

ented• 9 years ago

Why??????????????????????????

std_throwaway2• 9 years ago

It's a joke.

hinkley2• 9 years ago

Those who do not fear Poe's Law are doomed to repeat it.

ggdG• 9 years ago

They had me because it was so similar to the - very real - combinations of "conses" in the lisp world: caaaar, cdaddr, cddddr and so on. https://franz.com/support/documentation/6.0/ansicl/dictentr/...

TeMPOraL3• 9 years ago

"Science isn't about why - it's about why not. Why is so much of our science dangerous? Why not marry safe science if you love it so much?"

amelius• 9 years ago

Did you overload the "?" operator?

marcosdumay• 9 years ago

I think the parser will fail anyway. You can't overload syntax.

Sharlin• 9 years ago

I think you mean "Why??!??!??!??!??!??!??!??!??!" [1]

[1] https://stackoverflow.com/questions/7825055/what-does-the-c-...

lower2• 9 years ago

I remember this from a similar example in C:

   #include <stdio.h>
   int main()
   {
       int x = 10;
       while (x --> 0) /* x goes to 0 */
       {
          printf("%d ", x);
       }
   }

(prints 9 8 7 6 5 4 3 2 1 0)

https://stackoverflow.com/questions/1642028/what-is-the-oper...

fiddlerwoaroof• 9 years ago

Your description of the result is a valid Lisp expression. . .As long as one has defined a prints function.

jfktrey• 9 years ago

Works just as well in Java. I'll have to slip this in to my next code review :)

beeforpork2• 9 years ago

Careful with these jokes -- your coding style nazis will give you a new coding rule in return to prevent this madness in the future!

repsilat• 9 years ago

Yeah, `x --> 0` works. Also `0 <-- x` if you don't want to include zero (and `x --- 0` if you don't have a shift key.)

std_throwaway2• 9 years ago

In python there is the term "pythonic" describing if something is in the spirit of the languages founding fathers. As in: "The most pythonic way to write this down is ..." or "Map/filter don't feel very pythonic."

What is the equivalent term or expression for being in the spirit of C++?

The article, while a joke (just like C++ originally, look it up), feels very C++y.

xsmasher• 9 years ago

"Such-and-such is (not) idiomatic C++"

0xbear• 9 years ago

I don't think there's broadly "idiomatic" C++. There's "idiomatic Google C++" though.

pan69• 9 years ago

Not sure if there is such a thing but if not, maybe it could be "Stroubie".

TeMPOraL3• 9 years ago

As in something you could end up in? "Using long arrow operator in production will get you into strouble".

barsonme• 9 years ago

I think the word is "confusing"

TallGuyShort• 9 years ago

I was once taught, "In C, calling a solution 'interesting' is a compliment. In Python, that's an insult. Maybe we should go with "interesting".

skocznymroczny• 9 years ago

undefined behavior

hinkley2• 9 years ago

Stroustrupian

strictfp• 9 years ago

"This is not confusing enough to be considered C++"

Black-Plaid• 9 years ago

Possibly "Bjarney"

skj• 9 years ago

The article where bjarne describes C++ syntax as a joke and programmer job security is a parody.

http://www.snopes.com/computer/program/stroustrup.asp

wyldfire• 9 years ago

The code from the article isn't merely "not idiomatic C++", but I would go so far as to say it's abused or obfuscated C++.

An example of non-idiomatic C++ might be

    for (int I = 0; I < c.size(); I++) {
        Total += c[I].foo;
    }

...instead of using std::accumulate. The code from the article is (humorously pointing out) something else entirely.

marssaxman• 9 years ago

Either you come from a very different community of C++ users than I do, or you are using a different definition of "idiomatic" than I am familiar with, because that loop looks like totally ordinary, everyday C++, and is therefore precisely what I'd call "idiomatic", while I can't recall ever having seen anyone actually use std::accumulate in real life. I suppose this is part of the fun of C++, though, in that it supports a family of distinct but compatible dialects.

philipov• 9 years ago

Python has zen. Zen is the basis of what is considered pythonic. C++ does not have zen; the language was designed by committee.

AnimalMuppet• 9 years ago

Not really. C++ was designed by Stroustrup; a committee then modified it somewhat.

GuB-42• 9 years ago

Python has a strong sense of purity. It is a language that really guides you into doing things one way and the community reflect that.

Not so much with C++. There is no one way to do things. Depending on your needs, you will use the language differently. Code focused on performance (ex: game engine) will look very different from server code, or a GUI, or embedded software. And none will be more C++y than the other.

marklgr• 9 years ago

Obligatory "x slides to zero":

  while (x --\
              \
               \
                \
                 > 0)
       printf("%d ", x);

TeMPOraL3• 9 years ago

Also, never forget, the C++ Multi-Dimensional Analog Literals:

  assert( ( o-------------o
            |L             \
            | L             \
            |  L             \
            |   o-------------o
            |   !             !
            !   !             !
            o   |             !
             L  |             !
              L |             !
               L|             !
                o-------------o ).volume == ( o-------------o
                                              |             !
                                              !             !
                                              !             !
                                              o-------------o ).area * int(I-------------I) );

http://www.eelis.net/C++/analogliterals.xhtml

Longhanks• 9 years ago

This is some serious black magic. I cannot wrap my head around the fact that this is valid C++...

awinter-py• 9 years ago

and don't forget the equally useful and serious integer unary-double-equal greater-than operator

  8==>

digi_owl• 9 years ago

I guess if this was Reddit, we would have had a meme storm by now...

kuon2• 9 years ago

Even if it's a Joke, C++ lost me a decade ago...

sqeaky4• 9 years ago

That's a shame. C++11/14/17 each make the language better and deal with many of the might have pushed someone away in the past.

The typing is getting stronger, the library richer and hard things easier. If you know about or can google RAII and are willing to lookup things on occasion to pick algorithms or just the right member function, code gets very clean. After not too long the looking stops because the std lib is still pretty small compared to other languages.

But if you have already moved to Rust I can't make an objective argument for it.

jussij2• 9 years ago

C++11/14/17 each make the language better and deal

That may be true, but all you are seeing is C++ copying from every other language in an effort to once again become relevant.

IMHO in this modern day and age there are so many easier, better, more expressive, easier to use languages than C++ to choose from.

And that is coming from someone who spent a lot of time coding C++ some 15 years ago.

beeforpork2• 9 years ago

C++11+ is even more complex than before, so I disagree: C++ is worse now. Almost all the old crap still exists on top of the shiny new stuff.

Designing classes that distinguish & and && properly makes writing new types more difficult. You need even more boilerplate stuff now. Like: I define a '-' operator, but I don't automatically get a '-=' operator, WTF. And now I need to add a && version of the -= and += and = and to invoke move() correctly so the type system is pleased AND it won't crash. This is supposed to be used for application code, so why do we need so much brain capacity to handle it?

And I would really be interested in a survey to find our how many professional C++ programmers know the intricate rules behind overloading with template functions, template classes, inside and outside class scope, with namespaces, with & and &&, with const, with auto and lambda and maybe more etc. This is just too much!

Using classes is a bit better now (if they are written properly), but once you start defining your own types, its no fun anymore.

The nicest I can say about C++ is that it is fun if you want to experiment. But for a production system, it is not a good choice, because it is too complex.

kuon2• 9 years ago

I'm not using rust yet, I am mostly writing using higher level languages (python then elixir/erlang, also lua) with a few part in C when I need to do something C is good at.

Also enjoying elm for frontend.

Double_a_92• 9 years ago

Law of Demeter, much?

jussij2• 9 years ago

Is this an Aprils fools joke posted a few months late?

alejohausner2• 9 years ago

You can even approach 0 from left and right simultaneously:

    while (a -->> k --> 0 <-- b <<-- c)

and you can have dashed arrows too:

    k = a <- - - - - b;

cloop_floop• 9 years ago

this is beautiful AND insane bravo

trelliscoded• 9 years ago

In the dashed case, k is going to be zero or one (a<b is true or false). This works, though:

        int a=0, b=4;

        while(a < - - - - --b) {
                printf("b: %d\n", b);
        }

alejohausner2• 9 years ago

I just spent an hour constructing a class called Morse such that this outputs "HELLO WORLD!":

    Morse m;
    cout << (++++m) << (+m) << (+-++m) << (+-++m) << (---m) << ", "
         << (+--m) << (---m) << (+-+m) << (+-++m) << (-++m) << "!\n";

Damn you, C++! Why won't you let me overload the . operator? ;-)

The long arrow operator in C++

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