Re: Mutability
Re: Mutability
- Subject: Re: Mutability
- From: Ondra Cada <email@hidden>
- Date: Thu, 22 Nov 2001 23:30:39 +0100
John,
>
>>>>> John C. Randolph (JCR) wrote at Thu, 22 Nov 2001 12:05:29 -0800:
JCR> How about:
JCR> @interface NSArray (mutability)
JCR> @implementation NSArray (mutability)
JCR> @implementation NSMutableArray (mutability)
Looks like another nice idea, doomed to fail by the CoreFoundation black
magic (which I am quite inclined to call "a really buggy code" in this case):
=== just have a look ===
123 /tmp> cat q.m
#import <Foundation/Foundation.h>
@interface NSArray (MutabilityTrick)
-(BOOL)isMutable;
@end
@implementation NSArray (MutabilityTrick)
-(BOOL)isMutable {return NO;}
@end
@implementation NSMutableArray (MutabilityTrick)
-(BOOL)isMutable {return YES;}
@end
int main(void) {
id pool=[NSAutoreleasePool new];
id a=[NSArray array];
id b=[NSMutableArray array];
NSLog(@"a %@ %d %d %d",[a class],[a isKindOfClass:[NSMutableArray
class]],[a respondsToSelector:@selector(addObject:)],[a isMutable]);
NS_DURING [a addObject:@""]; NS_HANDLER NSLog(@"a IMMUTABLE!!!"); NS_ENDHANDLER
NSLog(@"b %@ %d %d %d",[b class],[b isKindOfClass:[NSMutableArray
class]],[b respondsToSelector:@selector(addObject:)],[b isMutable]);
NS_DURING [b addObject:@""]; NS_HANDLER NSLog(@"b IMMUTABLE!!!"); NS_ENDHANDLER
return 0;
}
124 /tmp> cc q.m -framework Foundation && ./a.out
2001-11-22 23:25:56.558 a.out[811] a NSCFArray 1 1 1
2001-11-22 23:25:56.559 a.out[811] a IMMUTABLE!!!
2001-11-22 23:25:56.560 a.out[811] b NSCFArray 1 1 1
125 /tmp>
=== end ===
Incidentally, what about checking the code before sending the idea out? ;)
---
Ondra Cada
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