Objective-C: Curly braces after variable declaration

Question

I'm trying to get a better understanding of good Objective-C/Swift practices, and I am currently reading this: https://github.com/facebook/pop/blob/master/pop/POPAnimatableProperty.mm , from the Awesome-iOS repo in GitHub. I don't understand these two bits of code.

1/

static POPStaticAnimatablePropertyState _staticStates[] =
{
  /* CALayer */

  {kPOPLayerBackgroundColor,
    ^(CALayer *obj, CGFloat values[]) {
      POPCGColorGetRGBAComponents(obj.backgroundColor, values);
    },
    ^(CALayer *obj, const CGFloat values[]) {
      CGColorRef color = POPCGColorRGBACreate(values);
      [obj setBackgroundColor:color];
      CGColorRelease(color);
    },
    kPOPThresholdColor
  },

  {kPOPLayerBounds,
    ^(CALayer *obj, CGFloat values[]) {
      values_from_rect(values, [obj bounds]);
    },
    ^(CALayer *obj, const CGFloat values[]) {
      [obj setBounds:values_to_rect(values)];
    },
    kPOPThresholdPoint
  },
...
}

I get the block part, that is:

 ^(CALayer *obj, CGFloat values[]) {
      POPCGColorGetRGBAComponents(obj.backgroundColor, values);
    }

What I don't get is the two curly braces right after

static POPStaticAnimatablePropertyState _staticStates[] =

What is it supposed to be?

2/Similar, but not identical, this piece of code:

static NSUInteger staticIndexWithName(NSString *aName)
{
  NSUInteger idx = 0;

  while (idx < POP_ARRAY_COUNT(_staticStates)) {
    if ([_staticStates[idx].name isEqualToString:aName])
      return idx;
    idx++;
  }

  return NSNotFound;
}

It seems to be a block of code after a variable declaration. Is it supposed to execute everytime the variable is used?

Answer 1

First one is declaring an array of POPStaticAnimatablePropertyState statically. It seems that POPStaticAnimatablePropertyState is a struct itself (possibly via typedef) which has a number, a block, another block, and another number.

Second one is just a static C function, nothing special there.

This code is not a good Objective-C/Swift practice. It's just regular plain C, possibly written to be easily ported or written in this way for pure performance.