Efective Objective C 2.0

gistfile1.txt

1. Prefer @class instead of #import as posible
  - In headers files use @class, in implementation file use #import
  - For protocol, separarte the protocol in other file (h)

2. Prefere literals instead of class methods
  @YES, @1, @5.45f, ...
  
3. Prefer static cons instead of prepocesor # define
  DURATION 0.3
  static const NSInterval duration = 0.3; this is visible in implementatio file only
  extern NSString * const text = @"Hola";
  - For constants in local files prefix kName
  - For constants Globals prefix CLASS_NAME