Datastructure / Class design in Cocoa

Discussion in 'Mac Programming' started by gekko513, Mar 16, 2006.

  1. gekko513 macrumors 603


    Oct 16, 2003
    Even though I've been dabbling in Cocoa for one and a half year now, I haven't gotten entirely comfortable with some of the design aspects of the Objective C / Cocoa / Xcode combo.

    What kind of files do I create to add new types and c functions for making them, like NSPoint and NSMakePoint(x, y).

    Lets say I want a type
    typedef struct {
      float a;
      float x;
      float y;
      float z;
    } ASRotation;
    ASMakeRotation(float a, float x, float y, float z);
    The definitions can't be in the .h file of an Objective C class, because you're not supposed to import the .h files of another Objective C class in the .h file of a class.

    Do I use New File -> BSD -> C File? Or something else?
  2. mrichmon macrumors 6502a

    Jun 17, 2003
    Yes, you use New File->BSD->C File and then give the file a .h name.
    Import the file where you need it using #import "foo.h".
  3. gekko513 thread starter macrumors 603


    Oct 16, 2003
    I went the BSD->C File way first. I need to implement the function somewhere too, so I had both a foo.c and a foo.h. I ran into trouble because when the when foo.c was compiled, none of the regular Cocoa headers where included, obviously, and that made it difficult to accomplish what I wanted.

    I decided to try the usual New File->Cocoa->Objective C class for a foo.m and foo.h combo and then just removed the @interface and @implementation sections, and that seems to work just the way I want.

    Are there any reasons that I have missed to why I shouldn't do it this way?
  4. HiRez macrumors 603


    Jan 6, 2004
    Western US
    I usually put such C struct/typedefs in the prefix file, which will automatically be available to all your Obj-C files. I don't know if that's good practice, but it seems to work. I also have the prefix file import all the large APIs I'm using (Cocoa, CoreAudio, QuickTime, or whatever), so I only have to do it once.
  5. gekko513 thread starter macrumors 603


    Oct 16, 2003
    How would you solve the issue of defining and declare functions for creating those structs, such as the ASMakeRotation function that I mentioned?
  6. savar macrumors 68000


    Jun 6, 2003
    District of Columbia
    It's not like the template you use affects how the file is read. All that matters is the extension, and in either case you've created a .h file. If you want access to Cocoa headers, then just include them. But there's nothing wrong with you've done.

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