Objective-C Minimalism

I often write small test projects on Objective-C to experiment or play with something. Usually, I put the code in main.m and get rid of everything else:

#!/usr/bin/env objc-run @import Foundation; @implementation Hello : NSObject - (void) sayHelloTo:name { printf("Hello %s, my address is %p\n", [name UTF8String], self); } @end int main () { id hello = [Hello new]; [hello sayHelloTo:@"sunshine"]; } 

This is a complete project from a single file, ready to run. Under the cut - a description of techniques that allowed to come to this minimalism.

• Everything is written in main.m. Or “Test.m”, or whatever. The main () function can be in any file.
• Use objc-run. If you haven't encountered it yet , objc-run is a great utility that “makes it easy to use Objective-C files as console script-like tasks.” Install it: brew install objc-run

brew install objc-run

and add permissions to execute your source file: chmod u+x main.m
• Modules instead of precompiled headers. Perhaps it makes sense in #imports and PCH in large projects, but for small test programs? No, really.
• No @interface ads I accidentally found out that ObjC allows you to specify a superclass directly in the @implementation directive. It is not entirely clear why this was allowed, but this allows you to completely get rid of the @interface block.
• Implicit types of parameters of functions. The return types and parameters of ObjC methods are implicitly equal (id), which means
  
  -(id)doSomethingWith:(id)param ; this is exactly the same as -doSomethingWith:param ; but the second option looks more convenient.
• No arguments in main (). Although this is considered a bad practice, it is perfectly acceptable to write void main () instead of int main (int argc, char**argv) . Why declare it all, if you still do not use these arguments?
• Get rid of return in main() . Starting from the C99 standard, when returning control from main() without a return statement, it is considered that return 0; was called return 0;
• printf instead of NSLog. NSLog - for error messages, not for text output - I do not need to display the path to the executable file and the thread ID on each line.

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Translator's note: in the absence of @interface warning warning annoys me:

 /dev/fd/63:3:17: warning: cannot find interface declaration for 'Hello' @implementation Hello : NSObject ^ 1 warning generated. 

This is a warn_undef_interface for which there is no corresponding -W flag (to silence warnings by type). So for myself, I left an empty interface.

 #!/usr/bin/env objc-run @import Foundation; @interface Hello : NSObject @end @implementation Hello - (void) sayHelloTo:name { printf("Hello %s, my address is %p\n", [name UTF8String], self); } @end int main () { id hello = [Hello new]; [hello sayHelloTo:@"sunshine"]; }