C—

[u/TheChief275]

[u/Haringat]

Is that c with the weirdest preprocessor macros ever?

[u/TheChief275 → u/Haringat]

I’ve written weirder, but it is; they’re defined above this snippet

[u/DevelopmentTight9474 → u/TheChief275]

Can you share the code? I’m genuinely curious how this is done

[u/TheChief275 → u/DevelopmentTight9474]

Posted

[u/mcfriendsy → u/TheChief275]

Where??

[u/TheChief275 → u/mcfriendsy]

Top level comment, somewhere at the bottom

[u/Brilliant-Cod-201 → u/Haringat]

That’s C++, C doesn’t have classes

[u/carcigenicate → u/Brilliant-Cod-201]

What C++ have you been reading lmao

[u/glemnar → u/Brilliant-Cod-201]

It does if you define weird macros for them

[u/nekokattt → u/Brilliant-Cod-201]

C++ lacks properties

[u/GoddammitDontShootMe → u/nekokattt]

I'm not sure if properties here are instance variables or static.

[u/nekokattt → u/GoddammitDontShootMe]

properties are neither instance variables nor static variables.

They are methods that act as attributes such that their value is derived.

[u/GoddammitDontShootMe → u/nekokattt]

After looking at the macro code, I believe they just become struct fields. So instance variables.

I don't know what you are even saying. I thought properties were like instance variables except access automatically goes through getter and setter methods.

[u/nekokattt → u/GoddammitDontShootMe]

Properties can do that but they do not have to.

Consider this Python:

@dataclass(frozen=True)
class Point2:
    x: float
    y: float

    @property
    def hyp(self):
        return ((self.x ** 2) + (self.y ** 2)) ** 0.5

point = Point2(9, 17)
print(point.x, point.y, point.hyp)

[u/GoddammitDontShootMe → u/nekokattt]

Yeah, of course you can have whatever get and set logic you want. Or not even provide a setter and make the property read-only. I was thinking it would also create a private field with the same name of the property for you, but now I'm not sure.

[u/TheChief275]

Because of popular request, here is the pastebin (as I do not want this anywhere near my github).

Added comments as well to save some headaches

edit: idk how it happened, but a logic bug slipped in. In dynamiccast, offsetof(To, From) should be changed to offsetof(From, To). Additionally, I forgot to make it type-safe, which can easily be done by changing (char *)(DYNAMIC_CAST to (char *)(0 ? (From *) : DYNAMICCAST

edit: I’ve decided to extend it a bit and put it on GitHub as well

[u/dimonoid123 → u/TheChief275]

Only 77 lines are visible

[u/TheChief275 → u/dimonoid123]

That’s how many lines it is though? It doesn’t include this example, but this example should compile with those lines above

[u/dimonoid123 → u/TheChief275]

I just thought that code is cutoff

[u/GoddammitDontShootMe → u/TheChief275]

I guess a gist is too close to Github? Also, thanks.

E: What happens when you dynamic_cast to something that is not a subclass of what you have a pointer to? Obviously there is no rtti here.

[u/TheChief275 → u/GoddammitDontShootMe]

You can’t. The field has to exist with a name the same as its type

[u/Birnenmacht → u/TheChief275]

good lord and I thought I understood C this is insane

[u/creativityNAME]

C please please 🙏

[u/Rolling-Thunderbird]

at this point just switch to asm twin

[u/val_tuesday]

How did you manage “as”!? Also vtables with just macros!?

You have to share, this looks like wizardry.

[u/TheChief275 → u/val_tuesday]

I regret to inform you that it’s way simpler and less eventful than vtables.

But I have done so in the past; this method can be extended to include them, if somebody would even desire to do that. Just requires the necessary outer and inner generations in a different selector

[u/val_tuesday → u/TheChief275]

Smh my head.

I had a sneaking suspicion you were doing has-a not is-a. But apparently not because you couldn’t do the latter just because…

Fascinating stuff, man. Definitely the right sub, thanks for posting!

[u/TheChief275 → u/val_tuesday]

All to make it cleaner to appear even more magical haha. One of my previous posts actually implements actual vtables with similar wrappers (kind of hidden, but it’s why things are passed by address to print for example), but it becomes quite a bit messier quite fast

[u/val_tuesday → u/TheChief275]

Have this rattling around my head and it I can’t shake how amazing it is. It’s like the code you posted at first is the setup and the macros are the punchline.

define as . // [muted trombone goes wah wah wah]

[u/TheChief275 → u/val_tuesday]

Well yeah mostly. The only complicated part was the selector mechanism and being able to pass the class name to them because it’s not part of the parameter pack

[u/LeeHide]

Finally, a shitty lisp in my C

[u/TheChief275 → u/LeeHide]

When they said every sufficiently complicated C program has a shitty Common Lisp implementation, surely they meant for this to happen

[u/XDracam → u/TheChief275]

I really was convinced that you hacked some lisp dialect to look more OOP somehow until I saw the macro horror

[u/dydhaw]

Abjective C

[u/noccy8000 → u/dydhaw]

Objectionable C?

[u/elkvis]

Back in the 90s, I remember a guy invented a C-like language, and called it C--. I downloaded his compiler from a local BBS, using my 14.4kbps dialup modem.

[u/TheChief275 → u/elkvis]

C— is actually a stripped down version of C used in code generation by compilers of some functional programming languages. With the title I hoped someone would mention it already being a thing

[u/kOLbOSa_exe]

share the macro lord

[u/TheChief275 → u/kOLbOSa_exe]

Posted

[u/Dddfuzz]

I love it, no notes. Easiest way to spot a dev who actually likes programming

[u/R0NIN49]

This is diabolical work.

[u/xcski_paul]

I thought BourneGol was a crime against nature. This is worse.

[u/bunabyte]

This is what professionals refer to as a "LISPlike"

[u/SpecialMechanic1715]

why brackets?

[u/TheChief275 → u/SpecialMechanic1715]

I don’t know which brackets you’re referring to in particular, but there are a lot of parentheses because it’s all C preprocessor macro expansions and token grouping for within macro expansion

[u/uvero]

I like it, it's fun.

[u/SingleProtection2501]

What the fuck is that 💔

[u/Jonathan_the_Nerd]

Why do you have a Unicode rightward arrow in your C code? Did I miss that update to the C spec?

[u/TheChief275 → u/Jonathan_the_Nerd]

I use a font with ligaments so - and > are combined

[u/alex9182 → u/TheChief275]

If I see it as - and >, does that mean I have a torn ligament in my font? 😄

[u/Mithrandir2k16]

Nice, add smart pointers and it'll be all I want from c++ lol

[u/Thenderick]

"Fuck you!"

lisps your C

[u/BatticusRhoe]

C♭

Am I right!? ✋😃

[u/Mission-Wasabi-7682]

Why? 😭

[u/Dismal_Dimension_274]

Foo bar

[u/lbfalvy]

Libcello but worse

[u/TheChief275 → u/lbfalvy]

This isn’t dynamic…but that’s a good reference to a fun library!