4 ms·

Don't do this at home. It looks so ugly because it's dangerous and vice-versa. If you really want to write (and read) code like this: id titleString = ((id (

Don't do this at home. It looks so ugly because it's dangerous and vice-versa. If you really want to write (and read) code like this: id titleString = ((id ()(id, SEL, const char))objc_msgSend)((id)objc_getClass("NSString"), sel_registerName("stringWithUTF8String:"), "sup from C"); ((void (*)(id, SEL, id))objc_msgSend)(window, sel_registerName("setTitle:"), titleString); instead of this [window setTitle:@"sup"]; then I guess it would be easier to write a Objective-C to C converter (if there isn't one already) and convert your Objective-C app into C for added coolness. I

deanCommie 10y ago
Seriously, I don't know who's downvoting you. This needs a huge "for academic purposes only disclaimer". Higher level abstractions exist for a reason.
- elsurudo 10y ago
  I think it's obvious that this is an academic exercise (or "just because I can" sort of thing), which makes the GP's comment quite unnecessary.
dmytroi 10y ago
One practical example would be tigr [1] - a cross platform window framework for making simple applications, could be compiled as one header drop-in only lib. You simply cannot make it one header without making calling ObjC runtime from C. Why it's necessary to make it work as one drop-in header? Well it's a new trend in C libraries, which allows using libraries with the least resistance possible, it's like a package manager but nicer - you only have one file! Great example of modern one header libs is probably the famous stb package [2]. - [1] https://bitbucket.org/rmitton/tigr/src https://bitbucket.org/rmitton/tigr/src - [2] https://github.com/nothings/stb https://github.com/nothings/stb
- btrask 10y ago
  I haven't looked at tigr yet (it seems interesting!) but could you just use '#ifdef __OBJC__'?
  - dmytroi 10y ago
    Not really, because everything is C/C++ there by means files are .c, .cpp and not .m or .mm, its a bit tricky from build system point of view to treat the file with extension .c/.cpp as Objective-C.
    - btrask 10y ago
      A .h file can be compiled as C, C++, or Objective-C. Isn't that how single-file libraries usually work?
      - dmytroi 10y ago
        Yes, and this .h file will be used from .c/.cpp because looks like it's way to bulky to add additional .m/.mm file just for OSX/iOS case when creating cross platform applications. Check tigr - it's possible to run exactly the same C/C++ code on Windows and OSX without any changes at all.
        comex 10y ago
        Since Objective-C is a true superset of C (unlike C++) and there's also Objective-C++, you can just tell the compiler to compile all .c/.cpp as if they were .m/.mm. That is, if you can figure out how to coax your build system to pass the right flags.
- fit2rule 10y ago
  For the record, this isn't a new trend - its been fashionable in C for decades to create single-header 'library' drop-ins and is pretty much par for the course ..
bluedino 10y ago
>> I guess it would be easier to write a Objective-C to C converter That's what the first Obj-C (and C++ compilers) were
- OJFord 10y ago
  Well, sure. But only in the same way that the first C compiler was a "machine code converter". * Or B, perhaps, if we're to be really pedantic.
bdrool 10y ago
> a Objective-C to C converter (if there isn't one already) Incidentally, that's pretty much how the language got started -- as a pre-processor add-on for plain C: https://en.wikipedia.org/wiki/Objective-C#History https://en.wikipedia.org/wiki/Objective-C#History
david-given 10y ago
There are Objective-C to C converters. http://users.telenet.be/stes/compiler.html http://users.telenet.be/stes/compiler.html However, the dialect this one implements is very different from Apple's, and it doesn't quite produce ANSI C (the generated code does some things which you can usually get away with but are technically illegal, like casting object pointers to function pointers). It's mainly of historical interest now.

deanCommie 10y ago

Seriously, I don't know who's downvoting you. This needs a huge "for academic purposes only disclaimer". Higher level abstractions exist for a reason.

elsurudo 10y ago
I think it's obvious that this is an academic exercise (or "just because I can" sort of thing), which makes the GP's comment quite unnecessary.

dmytroi 10y ago

One practical example would be tigr [1] - a cross platform window framework for making simple applications, could be compiled as one header drop-in only lib. You simply cannot make it one header without making calling ObjC runtime from C. Why it's necessary to make it work as one drop-in header? Well it's a new trend in C libraries, which allows using libraries with the least resistance possible, it's like a package manager but nicer - you only have one file! Great example of modern one header libs is probably the famous stb package [2]. - [1] https://bitbucket.org/rmitton/tigr/src https://bitbucket.org/rmitton/tigr/src - [2] https://github.com/nothings/stb https://github.com/nothings/stb

btrask 10y ago
I haven't looked at tigr yet (it seems interesting!) but could you just use '#ifdef __OBJC__'?
- dmytroi 10y ago
  Not really, because everything is C/C++ there by means files are .c, .cpp and not .m or .mm, its a bit tricky from build system point of view to treat the file with extension .c/.cpp as Objective-C.
  - btrask 10y ago
    A .h file can be compiled as C, C++, or Objective-C. Isn't that how single-file libraries usually work?
    - dmytroi 10y ago
      Yes, and this .h file will be used from .c/.cpp because looks like it's way to bulky to add additional .m/.mm file just for OSX/iOS case when creating cross platform applications. Check tigr - it's possible to run exactly the same C/C++ code on Windows and OSX without any changes at all.
      - comex 10y ago
        Since Objective-C is a true superset of C (unlike C++) and there's also Objective-C++, you can just tell the compiler to compile all .c/.cpp as if they were .m/.mm. That is, if you can figure out how to coax your build system to pass the right flags.
fit2rule 10y ago
For the record, this isn't a new trend - its been fashionable in C for decades to create single-header 'library' drop-ins and is pretty much par for the course ..

bluedino 10y ago

>> I guess it would be easier to write a Objective-C to C converter That's what the first Obj-C (and C++ compilers) were

OJFord 10y ago
Well, sure. But only in the same way that the first C compiler was a "machine code converter". * Or B, perhaps, if we're to be really pedantic.

bdrool 10y ago

> a Objective-C to C converter (if there isn't one already) Incidentally, that's pretty much how the language got started -- as a pre-processor add-on for plain C: https://en.wikipedia.org/wiki/Objective-C#History https://en.wikipedia.org/wiki/Objective-C#History

david-given 10y ago

There are Objective-C to C converters. http://users.telenet.be/stes/compiler.html http://users.telenet.be/stes/compiler.html However, the dialect this one implements is very different from Apple's, and it doesn't quite produce ANSI C (the generated code does some things which you can usually get away with but are technically illegal, like casting object pointers to function pointers). It's mainly of historical interest now.