gistfile1.matlab

// .h
@interface NSNull (null)
+ (void) setWarnsOnNullAccess:(BOOL) warnsOnNullAccess;

- (BOOL) boolValue;
- (char) charValue;
- (NSDecimal) decimalValue;
- (double) doubleValue;
- (float) floatValue;
- (int) intValue;
- (NSInteger) integerValue;
- (long long) longLongValue;
- (long) longValue;
- (short) shortValue;
- (unsigned char) unsignedCharValue;
- (NSUInteger) unsignedIntegerValue;
- (unsigned int) unsignedIntValue;
- (unsigned long long) unsignedLongLongValue;
- (unsigned long) unsignedLongValue;
- (unsigned short) unsignedShortValue;

- (id) valueForKey:(NSString *) key;

- (id) objectAtIndex:(NSUInteger) index;
- (id) objectAtIndexedSubscript:(NSUInteger) index;
- (NSUInteger) count;

- (id) objectForKey:(id) key;
- (id) objectForKeyedSubscript:(id) key;
- (NSUInteger) length;
@end

//  .m
#define PrintAccessLog(selector) \
	if (warnsOnNullAccess) { \
		NSLog(@"Attempting to access null value from \"%@\": %@", NSStringFromSelector(selector), [NSThread callStackSymbols]); \
	}

@implementation NSNull (null)
static BOOL warnsOnNullAccess = NO;
+ (void) setWarnsOnNullAccess:(BOOL) shouldWarnOnNullAccess {
	warnsOnNullAccess = shouldWarnOnNullAccess;
}

#pragma mark -

- (BOOL) boolValue {
	PrintAccessLog(_cmd)

	return NO;
}

- (char) charValue {
	PrintAccessLog(_cmd)

	return '\0';
}

- (NSDecimal) decimalValue {
	PrintAccessLog(_cmd)

	return [[NSDecimalNumber zero] decimalValue];
}

- (double) doubleValue {
	PrintAccessLog(_cmd)

	return 0.0;
}

- (float) floatValue {
	PrintAccessLog(_cmd)

	return 0.0;
}

- (int) intValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (NSInteger) integerValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (long long) longLongValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (long) longValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (short) shortValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (unsigned char) unsignedCharValue {
	PrintAccessLog(_cmd)

	return '\0';
}

- (NSUInteger) unsignedIntegerValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (unsigned int) unsignedIntValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (unsigned long long) unsignedLongLongValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (unsigned long) unsignedLongValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (unsigned short) unsignedShortValue {
	PrintAccessLog(_cmd)

	return 0;
}

- (id) valueForKey:(NSString *) key {
	PrintAccessLog(_cmd)

	return nil;
}

- (id) objectAtIndex:(NSUInteger) index {
	PrintAccessLog(_cmd)

	return nil;
}

- (id) objectAtIndexedSubscript:(NSUInteger) index {
	PrintAccessLog(_cmd)

	return nil;
}

- (NSUInteger) count {
	PrintAccessLog(_cmd)

	return 0;
}

- (id) objectForKey:(id) key {
	PrintAccessLog(_cmd)

	return nil;
}

- (id) objectForKeyedSubscript:(id) key {
	PrintAccessLog(_cmd)

	return nil;
}

- (NSUInteger) length {
	PrintAccessLog(_cmd)

	return 0;
}

#pragma mark NSString Messages

- (NSUInteger) _fastCharacterContents {
    PrintAccessLog(_cmd);
    
    return 0;
}

- (void)getCharacters:(unichar *)buffer range:(NSRange)range {
    PrintAccessLog(_cmd);
    assert(range.length == 0);
    assert(range.location == 0);
}

- (NSString *)substringFromIndex:(NSInteger)index {
    PrintAccessLog(_cmd);
    return nil;
}

@end