- @class
- @defs
- @protocol @required @optional @end
- @interface @public @package @protected @private @property @end
- @implementation @synthesize @dynamic @end
- @throw @try @catch @finally
- @synchronized @autoreleasepool
- @selector @encode
- @compatibility_alias
- @”string”
有些常用及不常用的compiler directive，不常用的，久了真的會忘，先記錄一下
