"for x in" syntax with NSArray - objective-c

Question

I've this kind of instruction:
[self someMethod:CGPointMake(50, 50)];
[self someMethod:CGPointMake(270, 50)];
[self someMethod:CGPointMake(50, 360)];
[self someMethod:CGPointMake(270, 360)];
...
I want to refactor code using NSArray like this:
NSArray items = [NSArray initWithObjects:
CGPointMake(50, 50),
CGPointMake(270, 50),
CGPointMake(50, 360),
CGPointMake(270, 360),
...
nil];
I dont know right syntax, can someone help me? I'd tried with this, but XCode tells me "Selector element type CGPoint is not a valid object":
CGPoint point = [CGPoint alloc];
for (point in items) {
[self someMethod:point];
}

Answer 1

for-in loops are an Objective-C concept for iterating over collection classes (that conform to NSEnumeration). If you would like to iterate over C-structs (like CGPoints), use a standard for-loop with a C-array, or wrap the CGPoints in NSValues.
Here's what your refactoring would look like in modern Objective-C syntax:
NSArray *items = #[
[NSValue valueWithPoint:CGPointMake(50, 50)], //wrap the points in an
[NSValue valueWithPoint:CGPointMake(270, 50)], //NSValue so they become
[NSValue valueWithPoint:CGPointMake(50, 360)], //first class citizens
[NSValue valueWithPoint:CGPointMake(270, 360)],//(Y no boxing?*)
]; //End of collection literal
for (NSValue *value in items) { //iterate through the NSValues with our points
[self someMethod:[value pointValue]]; //'un-wrap' the points by calling -pointValue
}
*My personal struct boxing macro:
#define STRUCT_BOX(x) [NSValue valueWithBytes:&x objCType:#encode(typeof(x))];

Answer 2

There's no need to resort to NSArray. As CodaFi says, "If you would like to iterate over C-structs (like CGPoints), use a standard for-loop with a C-array." Well then, why not do so?
static CGPoint items[] = {
{50, 50},
{270, 50},
{50, 360},
{270, 360},
};
#define ARRAY_SIZE(array) (sizeof(array) / sizeof(array[0]))
This creates the array at compile-time, not run-time! Then iterate the array:
for (NSUInteger i = 0; i < ARRAY_SIZE(items); ++i)
[self someMethod:items[i]];
For another example involving an array of dictionaries, see Objective-C Is Still C (Not Java!)