simple ObjC lazy getter macro

lazy_get.m

#import <Foundation/Foundation.h>

#define lazy_get(TYPE, NAME, VALUE) \
@synthesize NAME = _##NAME; \
- (TYPE)NAME { if (!_##NAME) _##NAME = (VALUE); return _##NAME; }

// example usage follows:

@interface LazyThing : NSObject

@property (nonatomic, readonly) NSString *lazyString;
@property (nonatomic, copy) NSString *aString;

@end

@implementation LazyThing

lazy_get(NSString *, lazyString, {
	NSString *a = @"a";
	NSString *b = @"b";
	[a stringByAppendingString:b];
})

lazy_get(NSString *, aString, {
	NSString *x = @"x";
	[x stringByAppendingString:[@(1) stringValue]];
})

@end