Dynamic properties

gistfile1.m

#import <objc/runtime.h>
#import <Foundation/Foundation.h>


@interface Person : NSObject
@property (nonatomic,strong) NSMutableDictionary *properties;
@end


@implementation Person

    -(id) init {
        self = [super init];
        if (self){
            _properties = [NSMutableDictionary new];
        }
        return self;
    }

    // generic getter
    static id propertyIMP(id self, SEL _cmd) {
        return [[self properties] valueForKey:NSStringFromSelector(_cmd)];
    }
    
    // generic setter
    static void setPropertyIMP(id self, SEL _cmd, id aValue) {
    	
        id value = [aValue copy];
        NSMutableString *key = [NSStringFromSelector(_cmd) mutableCopy];
      
        // delete "set" and ":" and lowercase first letter
        [key deleteCharactersInRange:NSMakeRange(0, 3)];
        [key deleteCharactersInRange:NSMakeRange([key length] - 1, 1)];
        NSString *firstChar = [key substringToIndex:1];
        [key replaceCharactersInRange:NSMakeRange(0, 1) withString:[firstChar lowercaseString]];
      
        [[self properties] setValue:value forKey:key];
    }

    + (BOOL)resolveInstanceMethod:(SEL)aSEL {
        if ([NSStringFromSelector(aSEL) hasPrefix:@"set"]) {
            class_addMethod([self class], aSEL, (IMP)setPropertyIMP, "v@:@");
        } else {
            class_addMethod([self class], aSEL,(IMP)propertyIMP, "@@:");
        }
        return YES;
    }

@end


int main(int argc, char *argv[]) {
	@autoreleasepool {
		Person *p = [Person new];
		[p setName:@"Jon"];
		NSLog(@"%@",[p name]);
	}
}