This document provides a brief history of Objective-C and its origins from Smalltalk in the late 1970s and early 1980s. It discusses how Objective-C was created as a pre-processor for C by Tom Love and Brad Cox at their company StepStone in the early 1980s. It then summarizes key developments like NeXT adopting Objective-C in the late 1980s, Apple acquiring NeXT and Objective-C in 1996, and improvements to Objective-C over time, including Objective-C 2.0 announced in 2006.

1. Objective-C
Um pouco de arqueologia
Tales Pinheiro
@talesp, tales@newtlabs.com

2. Mestre em computação pelo IME/USP
Head of Technologies na Newt Labs
Dev iOS na Shopcliq (http://shopcliq.com.br)
Incentivador da @selfsp NSCoder Night
http://meetup.com/NSCoder-Night-self-SP/
[self SP]; //http://groups.google.com/forum/#!forum/selfsp
Tales Pinheiro de Andrade

3. Charles Babbage
Augusta Ada King

4. Analyticlal Engine Order Code
CPC Building Scheme
Boehm Unnamed Coding system
Sequentielle Formelübersetzung
40s - Primeiras linguagens

5. Fortran
Speedcoding
Laning and Zieler
IT
Algol
Simula
CPL
Primeiras linguagens “Modernas”

6. BCPL B C
Smalltalk
Paradigmas fundamentais

7. Smalltalk
One day, in a typical PARC hallway bullsession, Ted
Kaehler, Dan Ingalls, and I were standing around talking
about programming languages. The subject of power came
up and the two of them wondered how large a language one
would have to make to get great power. With as much
panache as I could muster, I asserted that you could define
the “most powerful language in the world” in “a page of
code.” They said, “Put up or shut up.”
http://gagne.homedns.org/~tgagne/contrib/EarlyHistoryST.html

8. Origem
1981: Apresentação de Smalltalk na ITT Research Laboratory
Artigo sobre Smalltalk-80 na Byte Magazine
Se mudam para Schlumberger Research Labs
Tom Love adquire licença do Smalltalk-80
Se torna o primeiro cliente comercial
Cox e Love aprendem Smalltalk com a revista, código fonte
e suporte

9. I could built a Smalltalk pre-processor for C
in a couple of weeks: it’s just what we need

10. OOPC
1981 - Object Oriented Pre-Processor
ITT Research Laboratory, junto com Tom Love
sed, awk, compilador C...
1982 - Cox e Love deixam a Schlumberger Research Labs
Fundam a Productivity Products International (PPI)
Renomeada para StepStone (após investimento de VC)

11. Objective -C - Primeira versão
1982 - Desenvolvimento do pre-compilador
lex/yacc
1983 - Inicio da comercialização do Objective-C
Adiciona algumas bibliotecas de classes
1986 - Lançado Object Oriented Programming - An
evolutionary approach

12. About that time Bjarne [Stroustrup] heard about
our work and invited me to speak at Bell Labs,
which was when I learned he was working on C++.
Entirely different notions of what object-oriented
meant. He wanted a better C (silicon fab line). I
wanted a better way of soldering together
components originally fabricated in C to build
larger-scale assemblies.
http://moourl.com/89918
‘Concorrência” com C++

13. Primeira aparição da Apple
Apple é uma da primeiras interessadas no Objective-C
Além de Clascal, Object Pascal, Dylan*
“They did like PPI/Stepstone because we did such a good job
finding errors in their C compiler!"
https://www.youtube.com/watch?v=mdhl0iiv478

14. NeXT
1985 - Jobs deixa a Apple e funda a NeXT
NeXT “vai as compras” de tecnologia
1988 - NeXT licencia uso de Objective-C da Stepstone
NeXTStep (OS) e o OpenStep (APIs)
Application Kit e Foundation Kit
Protocolos (conceito, mas não implementação, de herança
multipla)

15. Objective-C open source
1988 - NeXT adiciona suporte ao GCC
Mas não liberam AppKit e Foundation
1992 - GNUStep: primeira implementação GPL incluindo
runtime e libs
1993 - GNU Objective-C runtime

16. NeXT adquire Objective-C
1995 - NeXT adquire marcas e direitos do Objective-C
Vende de volta licença de uso para Stepstone
http://moourl.com/89918

17. Apple adquire NeXT
1996 - Apple adquire NeXT
Usa NeXTStep como base para criar o Mac OS X
Usa a especificação do OpenStep para criar a Cocoa
Anos depois, transforma Project Builder no Xcode

18. Objective-C 2.0
Anunciado na WWDC 2006
Garbage Collector (apenas no Mac OS X)
Melhorias de sintaxe
Melhorias no runtime
Suporte 64 bits
Disponibilizado no Mac OS X 10.5 (Leopard) em 2007

19. Objective-C 2.0
Melhorias na sintaxe
@property e @synthesize (ou @dynamic)
Protocolos com @optional e @required
Dot Syntax
Fast enumeration
Extensões de classe

20. @property e @synthesize - Antes
@interface Person : NSObject {
// instance variables
NSString *_name;
}
- (NSString*)name;
- (void)setName:(NSString*)aName;
@end
@implementation Person
- (NSString*)name {
return _name;
}
- (void)setName:(NSString *)aName {
if (aName != _name) {
[_name release];
}
_name = [aName retain];
}
@end

21. @property e @synthesize - Depois
@interface Person : NSObject
@property (retain) NSString *name;
@end
@implementation Person
@synthesize name;
@end

22. Atributos para @property
Variáveis de instância publicas (@private e @protected)
Acesso: readonly (gera apenas o getter)
Semantica de armazenamento: assign, copy e retain
Thread safe: nonatomic
Permite nomear o getter

23. Atributos e getter nomeado
@interface Person : NSObject {
@private
int age;
@protected
BOOL active;
}
@property (retain) NSString *name;
@property (assign) int age;
@property (assign, getter = isActive) BOOL active;
@end
@implementation Person
@synthesize name = _name;
- (void)doSomething {
Person *aPerson = [[Person alloc] init];
if ([aPerson isActive]) {
[aPerson setActive:NO];
}
}
@end

24. @property e @synthesize
Key Value Coding:
NSString *name = [person valueForKey:@"name"];
[person setValue:@"Tales" forKey:@"name"];

25. Dot notation
Inicialmente, envio de mensagem era feito através de
@property (retain) NSString *name;
[person name];
[person setName:@”Tales”];
Com Dot notation, é possível usar
NSString *name = person.name;
person.name = @"John";
Ainda é enviada mensagem

26. Dot notation
Permite “aberrações”
NSMutableArray *mutableArray = NSArray.alloc.init.mutableCopy;
Envio de mensagem pode causar problemas de performance
Sobre-uso (@property vs métodos)
Person *p = [[Person alloc] init];
NSArray *thePeople = [NSArray arrayWithObject:p];
NSInteger numberOfPersons = thePeople.count;

27. Fast enumaration - Antes
Usando NSEnumerator
@interface Person : NSObject
@property (retain) NSString *name;
@property (assign) int age;
@end
@implementation Person
- (void)doSomething {
NSArray *thePeople = [NSArray array];
// Using NSEnumerator
NSEnumerator *enumerator = [thePeople objectEnumerator];
Person *p;
while ((p = [enumerator nextObject]) != nil) {
NSLog(@"%@ is %i years old.", [p name], [p age]);
}
}
@end

28. Fast enumaration - Antes
Usando indices
@interface Person : NSObject
@property (retain) NSString *name;
@property (assign) int age;
@end
@implementation Person
- (void)doSomething {
NSArray *thePeople = [NSArray array];
// Using indexes
for (int i = 0; i < [thePeople count]; i++) {
Person *p = [thePeople objectAtIndex:i];
NSLog(@"%@ is %i years old.", [p name], [p age]);
}
}
@end

29. Fast enumaration - Depois
@interface Person : NSObject
@property (retain) NSString *name;
@property (assign) int age;
@end
@implementation Person
- (void)doSomething {
NSArray *thePeople = [NSArray array];
// Using fast enumeration
for (Person *p in thePeople) {
NSLog(@"%@ is %i years old.", [p name], [p age]);
}
}
@end

30. Modern Objective-C
Xcode 4 - Apple troca GCC por LLVM
Automatic Reference Counting
Blocks
Literais
@property com @synthesize padrão
NSDictionary e NSArray subscripting
iVar no bloco @implementation

31. Blocks
Adição ao C (e por extensão, ao Objective-C e ao C++) ainda
não padronizada
Sintaxe inspirada em expressões lambda para criação de closures
OS X 10.6+ e iOS 4.0+
Bibliotecas de terceiros permitem OS X 10.5 e iOS 2.2+
Foco no uso com GCD

32. http://blog.bignerdranch.com/3001-cocoa-got-blocks/
http://vimeo.com/68340179

33. Literais - antes
NSNumber *number = [NSNumber numberWithInt:0];
NSArray *array = [NSArray arrayWithObjects:@"nome", @"sobrenome", nil];
NSDictionary *dict = [NSDictionary dictionaryWithObjects:@"Tales", @"Pinheiro"
forKeys:@"nome", @"sobrenome"];

34. Literais - depois
NSNumber *number = @0;
NSArray *array = @[@"nome", @"sobrenome"];
NSDictionary *dict = @{@"nome": @"Tales", @"sobrenome": @"Pinheiro"};

35. Default @synthesize
Não é mais necessário o @synthesize para uma @property
Compilador/runtime declaram automagicamente, equivalente a
@synthesize name = _name;

36. Subscripting
LLVM 4.0 ou posterior
Transforma
id object1 = [someArray objectAtIndex:0];
id object2 = [someDictionary objectForKey:@"key"];
[someMutableArray replaceObjectAtIndex:0 withObject:object3];
[someMutableDictionary setObject:object4 forKey:@"key"];}
Em
id object1 = someArray[0];
id object2 = someDictionary[@"key"];
someMutableArray[0] = object3;
someMutableDictionary[@"key"] = object4;

37. Subscripting
Custom classes também permitem
Indexada:
- (id)objectAtIndexedSubscript:(NSUInteger)idx;
- (void)setObject:(id)obj atIndexedSubscript:(NSUInteger)idx;
Por chave:
- (id)objectForKeyedSubscript:(id <NSCopying>)key;
- (void)setObject:(id)obj forKeyedSubscript:(id <NSCopying>)key;

38. Subscripting
É poder (http://nshipster.com/object-subscripting/)
Permite criação de DSL
routes[@"GET /users/:id"] = ^(NSNumber *userID){
// ...
}
id piece = chessBoard[@"E1"];
NSArray *results = managedObjectContext[@"Product WHERE stock > 20"];
“Com grandes poderes vêm grandes responsabilidades”
BEN, Tio

39. O futuro
Módulos! Yay o/
http://llvm.org/devmtg/2012-11/Gregor-Modules.pdf
http://clang.llvm.org/docs/Modules.html
Já disponível no Clang 3.4 (C e C++)
Headers são frageis e adicionam peso ao compilador

40. A fragilidade dos Headers
#define FILE "MyFile.txt"
#include <stdio.h>
int main() {
printf(“Hello, world!n”);
}

41. A fragilidade dos Headers
#define FILE "MyFile.txt"
// stdio.h
typedef struct {
//...
} FILE;
// on and on...
int main() {
printf(“Hello, world!n”);
}

42. A fragilidade dos Headers
#define FILE "MyFile.txt"
// from stdio.h
typedef struct {
//...
} “MyFile.txt”;
// on and on...
int main() {
printf(“Hello, world!n”);
}

43. Tamanho dos headers
#include <stdio.h>
int main() {
printf(“Hello, world!n”);
}
#include <iostream>
int main() {
std::cout << “Hello, world!”
}
C C++
Fonte
Headers
64 81
11.072 1.161.003

44. Módulos
import std; //#include <stdio.h>
int main() {
printf(“Hello, World!n”);
}
import permite adicionar um módulo nomeado
Ignora macros de pre-processador

45. Módulos
import std.stdio;
int main() {
printf(“Hello, World!n”);
}
import permite modo seletivo

46. Módulos
Vejam sessão 404 da WWDC 2013

47. Obrigado :D