Smalltalk is an object-oriented programming language and environment. It uses everything is an object and message passing paradigms. Some key aspects include: objects can have methods and fields, method calls use message passing syntax instead of function syntax, types are dynamically checked, and it has features like closures, reflection, and automatic memory management via garbage collection. The Smalltalk environment has been used for over 50 years and current implementations like Squeak and Pharo remain actively developed.

1. Smalltalk
Damien Cassou

2. ☠ ?

3. New tools

7. New books

10. New interests

13. Used?

15. 20%

16. 1,600
simultaneous users

17. 5,000
bookings/day

18. 10,000
updates/day

19. 1.9 billion
objects

20. guess what?

21. everything in
Smalltalk

27. Portable?

34. SqueakNOS

37. 2147483647 + 1
=
-2147483648

38. 2147483647 + 1
=
-2147483648
Java

39. 2147483647 + 1
=
2147483648
Smalltalk

40. 100 factorial
=

41. 100 factorial
=
9332621544394415268169923885626670
0490715968264381621468592963895217
5999932299156089414639761565182862
5369792082722375825118521091686400
0000000000000000000000

42. Concepts

43. Object
oriented

44. Everything is
an object

45. methods numbers
Everything is
classes
an object
tools
method calls
call stack

46. Method calls

47. postman.send(mail,recipient);

48. postman.send(mail,recipient);

49. postman.send(mail,recipient;

50. postman.send(mail to,recipient.

51. postman.send(mail,recipient);
postman send: mail to: recipient.

52. Unary
methods

53. 'Smalltalk' size
String
size

54. Binary
methods

55. 1+2
Number
+ aNumber

56. Dynamically
typed

57. ArrayList<String> strings
= new ArrayList<String>();
strings := ArrayList new.

58. Closures

59. ArrayList<String> strings
= new ArrayList<String>();
for(Person person: persons)
strings.add(person.name());
strings := persons collect:
[:person |
person name].
Collection
collect: aBlock

60. Thread regThread = new Thread(
new Runnable() {
public void run() {
this.doSomething();
}
});
regThread.start();
Block
[self doSomething] fork. fork

61. Garbage
collector

62. <= aPoint
^ x <= (aPoint x)
and: [y <= (aPoint y)]
Point
x
y
(2@3) <= (5@6) <= aPoint
Number
@ aNumber

63. Constructors

64. Control
structures

65. max: aNumber
(self < aNumber)
ifTrue: [^ aNumber]
ifFalse: [^ self]
Number
max: aNumber
ifTrue: t ifFalse: f
^ t value
ifTrue: t ifFalse: f
^ f value

66. pharo-project.org