Reflection/List properties: Difference between revisions

=={{header|Objective-C}}==

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

#import <objc/runtime.h>

@interface Foo : NSObject {

int exampleIvar;

}

@property (nonatomic) double exampleProperty;

@end

@implementation Foo

- (instancetype)init {

self = [super init];

if (self) {

exampleIvar = 42;

_exampleProperty = 3.14;

}

return self;

}

@end

int main() {

id obj = [[Foo alloc] init];

Class clazz = [obj class];

NSLog(@"\Instance variables:");

unsigned int ivarCount;

Ivar *ivars = class_copyIvarList(clazz, &ivarCount);

for (unsigned int i = 0; i < ivarCount; i++) {

Ivar ivar = ivars[i];

const char *name = ivar_getName(ivar);

const char *typeEncoding = ivar_getTypeEncoding(ivar);

// for simple types we can use Key-Value Coding to access it

// but in general we will have to use object_getIvar and cast it to the right type of function

// corresponding to the type of the instance variable

id value = [obj valueForKey:@(name)];

NSLog(@"%s\t%s\t%@", name, typeEncoding, value);

}

free(ivars);

NSLog(@"");

NSLog(@"Properties:");

unsigned int propCount;

objc_property_t *properties = class_copyPropertyList([Foo class], &propCount);

for (unsigned int i = 0; i < propCount; i++) {

objc_property_t p = properties[i];

const char *name = property_getName(p);

const char *attributes = property_getAttributes(p);

// for simple types we can use Key-Value Coding to access it

// but in general we will have to use object_getIvar and cast it to the right type of function

// corresponding to the type of the instance variable

id value = [obj valueForKey:@(name)];

NSLog(@"%s\t%s\t%@", name, attributes, value);

}

free(properties);

return 0;

}</lang>

{{out}}

<pre>

Instance variables:

exampleIvar i 42

_exampleProperty d 3.14

Properties:

exampleProperty Td,N,V_exampleProperty 3.14

</pre>