Pomelo Lee workspace

 @interface Person : NSObject
 @property (readonly) NSString *firstName;
 @property (readonly) NSString *lastName;
 @property int yearOfBirth;
 - (void)sayHello;
 - (void)saySomething:(NSString *)someWords;
 @end

#import "XYZPerson.h"
@implementation XYZPerson
- (void)sayHello {
    [self saySomething:@"Hello, world!"];
}
 
- (void)saySomething:(NSString *)someWords{
    NSLog(@"%@", someWords);
}
@end

[zhoulw saySomething:@"shut up!"];

SomeObject *newObject = [[SomeObject alloc] initWithInt:30];

SomeObject *newObject = [SomeObject new];

NSNumber *magicNumber = [NSNumber numberWithInt:42];

NSString *name = @"zlw";

    if (somePerson) {
        // somePerson points to an object
    }

   @synthesize firstName = ivar_firstName;
   ...
   NSString* firstName = [personZlw firstName];
   firstName = personZlw.firstName;
   firstName = ivar_firstName;
   [personZlw setFirstName:@"zhoulw"];

   @property (weak) id delegate;
   NSObject * __weak weakVariable;

   @property (unsafe_unretained) NSObject *unsafeProperty;
   NSObject * __unsafe_unretained unsafeReference;

   NSMutableString *nameString = [NSMutableString stringWithString:@"John"];
   self.badgeView.firstName = nameString;
   [nameString appendString:@"ny"];
   ...
   //直接赋值时别忘记copy
   _instanceVariableForCopyProperty = [aString copy];

   void (^simpleBlock)(void) = ^{
        NSLog(@"This is a block");
   };
   ...
   simpleBlock();

   double (^multiplyTwoValues)(double, double) =
                              ^(double firstValue, double secondValue) {
                                  return firstValue * secondValue;
                              };
    double result = multiplyTwoValues(2,4);
    NSLog(@"The result is %f", result);

   int anInteger = 42;
    void (^testBlock)(void) = ^{
        NSLog(@"Integer is: %i", anInteger);
    };
    anInteger = 84;
    testBlock(); //42

   __block int anInteger = 42;
    void (^testBlock)(void) = ^{
        NSLog(@"Integer is: %i", anInteger);
        anInteger = 100;
    };
    anInteger = 48;
    testBlock();//48
    NSLog(@"Value of original variable is now: %i", anInteger);//100

   typedef void (^XYZSimpleBlock)(void);
   XYZSimpleBlock anotherBlock = ^{
      ...
   };
   - (void)beginFetchWithCallbackBlock:(XYZSimpleBlock)callbackBlock {
      ...
      callbackBlock();
   }