Merge branch 'master' of https://github.com/objc-zen/objc-zen-book

Author: luca-bernardi

README.md

@@ -637,7 +637,7 @@ In case you don't override `initWithNibName:bundle:` and the caller decides to i
 
 Even though it should be possible to infer what method is the designate initializer, it is always good to be clear and explicit (the future you or other developers that will work on your code will thank you). There are two strategies (non mutually exclusive) that you can decide to use: the first one you is to clearly state in the documentation which initializer is the designated one, but better yet you can be nice with your compiler and by using the compiler directive `__attribute__((objc_designated_initializer))` you can signal your intent.
 Using that directive will also helps the compiler helping you and in fact the compiler will issue a warning if in your new designate initializer you don't call your superclass's designated initializer.
-There are, though, cases in which not calling the class designated initializer (and in turn providing the required parameters) and calling another designated initializer in the class hierarchy will bring the class in an useless state. Referring to the previous example, there is no point in instantiate a `ZOCNewsViewController` that should present a news, without the news itself. In this case you can enforce even more the need to call a very specific designated initializer by simply making all the other designated initializers not available. It is possible to do that by using another compiler directive `__attribute__((unavailable("Invoke the designated initializer"))) `, decorating a method with this attribute will make the compiler issuing an error if you try to call this method.
+There are, though, cases in which not calling the class designated initializer (and in turn providing the required parameters) and calling another designated initializer in the class hierarchy will bring the class in an useless state. Referring to the previous example, there is no point in instantiating a `ZOCNewsViewController` that should present a news, without the news itself. In this case you can enforce even more the need to call a very specific designated initializer by simply making all the other designated initializers not available. It is possible to do that by using another compiler directive `__attribute__((unavailable("Invoke the designated initializer"))) `, decorating a method with this attribute will make the compiler issuing an error if you try to call this method.
 
 Here the header relative to the implementation of the previous example (note the use of macros to don't repeat the code and being less verbose).
 
@@ -717,9 +717,9 @@ This pattern is very useful because removes the complexity of this initializatio
 Class clusters are widely used in the Apple's frameworks; some of the most notably examples are `NSNumber` that can return an appropriate subclass depending of the type of number provided (Integer, Float, etc...) or `NSArray` that will return a concrete subclass with the best storage policy.
 The beauty of this pattern is that the caller can be completely unaware of the concrete subclass; in fact it can be used when designing a library to be able to swap the underlaying returned class without leaking any implementation detail as long as is respectful of the contract established in the abstract class.
 
-In our experience the use of a Class Cluster can very helpful in removing a lot of conditional code.
-A typical example of this is when you have  the same UIViewController subclass for both iPhone and iPad, but the behavior is slightly different depending on the the device.
-The naïve implementation is to put some conditional code checking the device in the methods where the different logic is needed, even thought initially the place where this conditional logic is applied may be quite few they naturally tend to grow producing and explosion of code paths.
+In our experience the use of a Class Cluster can be very helpful in removing a lot of conditional code.
+A typical example of this is when you have the same UIViewController subclass for both iPhone and iPad, but the behavior is slightly different depending on the the device.
+The naïve implementation is to put some conditional code checking the device in the methods where the different logic is needed, even though initially the place where this conditional logic is applied may be quite few they naturally tend to grow producing an explosion of code paths.
 A better design can be achieved by creating an abstract and generic view controller that will contain all the shared logic and then two specializing subclass for every device. 
 The generic view controller will check the current device idiom and depending on that it will return the appropriate subclass.
 
@@ -1963,7 +1963,7 @@ As code as the one above is ugly, often it'd be better to design the architectur
 
 ### Multiple Delegation
 
-Multiple delegation is a very fundamental concept than unfortunately the majority of developers are hardly familiar with and too often NSNotifications are used instead. As you may have noticed, delegation and datasource are inter-object communication pattern involving only 2 objects: 1 delegant and 1 delegate.
+Multiple delegation is a very fundamental concept that, unfortunately, the majority of developers are hardly familiar with and too often NSNotifications are used instead. As you may have noticed, delegation and datasource are inter-object communication pattern involving only 2 objects: 1 delegant and 1 delegate.
 
 DataSource pattern is forced to be 1 to 1 as the information the sender asks for can be provided by one and only one object. Things are different for the delegate pattern and it would be perfectly reasonable to have many delegate objects waiting for the callbacks.