As presented at The Perl Conference 2017 on 19 Jun 2017

1. A Modest
Introduction
To Swift
The Perl Conference 2017
19 Jun 2017
John SJ Anderson
@genehack

2. @genehack › Intro to Swift › TPC 2017
Sorry!

3. @genehack › Intro to Swift › TPC 2017
Hi I'm John
aka @genehack
• VP Tech, Infinity Interactive
• Perl tribe
• Polyglot coder
• Just this guy, you know?

4. Polyglotism

6. @genehack › Intro to Swift › TPC 2017
Swift?

7. @genehack › Intro to Swift › TPC 2017
Introduced in 2014

8. @genehack › Intro to Swift › TPC 2017
Went Open Source
at version 2.2

9. @genehack › Intro to Swift › TPC 2017
Version 3.1 just released
(in March)

10. @genehack › Intro to Swift › TPC 2017
Version 4 coming
Real Soon Now

11. @genehack › Intro to Swift › TPC 2017
Originally MacOS only

12. @genehack › Intro to Swift › TPC 2017
Now on Linux too.

14. @genehack › Intro to Swift › TPC 2017
Android in the works!

17. @genehack › Intro to Swift › TPC 2017
Android in the works!DONE!!

18. @genehack › Intro to Swift › TPC 2017
Windows too?

19. https://swiftforwindows.codeplex.com/

20. @genehack › Intro to Swift › TPC 2017
Originally targeted
MacOS, iOS,
watchOS, and tvOS

21. @genehack › Intro to Swift › TPC 2017
With expanded platform
support, offers potential
"single-language stack"
advantages a la Node

22. So what's it like, man?

23. First, a brief digression…

24. @genehack › Intro to Swift › TPC 2017
How many MacOS / iOS
users do we have here?

25. @genehack › Intro to Swift › TPC 2017
How many MacOS / iOS
developers do we have?

26. @genehack › Intro to Swift › TPC 2017
The dirty little secret of
developing for Apple

27. @genehack › Intro to Swift › TPC 2017
From In The Beginning
Was The Command Line
by Neal Stephenson

28. @genehack › Intro to Swift › TPC 2017
Weird Pascal-based
naming and calling
conventions

29. @genehack › Intro to Swift › TPC 2017
HANDLES?!?

30. @genehack › Intro to Swift › TPC 2017
ObjectiveC's "syntax"

31. Swift is the Mac of Apple
programming languages

32. Swift Syntax

33. @genehack › Intro to Swift › TPC 2017
Comments
// this is a comment

34. @genehack › Intro to Swift › TPC 2017
Comments
/* this is a
multi-line
comment */

35. @genehack › Intro to Swift › TPC 2017
Comments
/* this is a
/* _nested_
multi-line comment, */
which is cool! */

36. @genehack › Intro to Swift › TPC 2017
Comments
/// doc comment

37. @genehack › Intro to Swift › TPC 2017
Variables
var foo = 1
var bar: Int
var baz = "whee!"

38. @genehack › Intro to Swift › TPC 2017
Variables
var foo = 1
var bar: Int
var baz = "whee!"

39. @genehack › Intro to Swift › TPC 2017
Variables
var foo = 1
var bar: Int
var baz = "whee!"

40. @genehack › Intro to Swift › TPC 2017
Variables
var foo = 1
var bar: Int
var baz = "whee!"

41. @genehack › Intro to Swift › TPC 2017
Variables
let bar = 1
bar += 1
// ^^ compile time error!

42. @genehack › Intro to Swift › TPC 2017
Variables
let bar = 1
bar += 1
// ^^ compile time error!

43. @genehack › Intro to Swift › TPC 2017
Variables
let bar
// also a compile time error
/*
You canNOT have an uninitialized and
untyped variable. You also can't use
an uninitialized variable _at all_
*/

44. @genehack › Intro to Swift › TPC 2017
Variables
let bar
// also a compile time error
/*
You canNOT have an uninitialized and
untyped variable. You also can't use
an uninitialized variable _at all_
*/

45. How friggin' awesome is that?

46. @genehack › Intro to Swift › TPC 2017
Operators

47. @genehack › Intro to Swift › TPC 2017
Flow Control
let n = 1
if n > 1 {
print("we got a big N here")
}

48. @genehack › Intro to Swift › TPC 2017
Flow Control
let n = 1
if n > 1 {
print("we got a big N here")
}

49. @genehack › Intro to Swift › TPC 2017
Flow Control
let n = 1
if n > 1 {
print("we got a big N here")
}

50. @genehack › Intro to Swift › TPC 2017
Flow Control
let arr = [ 1, 2, 3, 4]
var sum = 0
for elem in arr {
sum += elem
}
// sum now is 10

51. @genehack › Intro to Swift › TPC 2017
Flow Control
let arr = [ 1, 2, 3, 4]
var sum = 0
for elem in arr {
sum += elem
}
// sum now is 10

52. @genehack › Intro to Swift › TPC 2017
Flow Control
let arr = [ 1, 2, 3, 4]
var sum = 0
for elem in arr {
sum += elem
}
// sum now is 10

53. @genehack › Intro to Swift › TPC 2017
Flow Control
let arr = [ 1, 2, 3, 4]
var sum = 0
for elem in arr {
sum += elem
}
// sum now is 10

54. @genehack › Intro to Swift › TPC 2017
Flow Control
for index in 1 ... 10 {
# do something 10 times
}

55. @genehack › Intro to Swift › TPC 2017
Flow Control
for index in 1 ... 10 {
# do something 10 times
}

56. @genehack › Intro to Swift › TPC 2017
Flow Control
for index in 1 ..< 10 {
# do something 9 times
}

57. @genehack › Intro to Swift › TPC 2017
Flow Control
for index in 1 ..< 10 {
# do something 9 times
}

58. @genehack › Intro to Swift › TPC 2017
Flow Control
var countDown = 5
while countDown > 0 {
countDown--
}

59. @genehack › Intro to Swift › TPC 2017
Flow Control
var countDown = 5
while countDown > 0 {
countDown--
}

60. @genehack › Intro to Swift › TPC 2017
Flow Control
var countDown = 5
while countDown > 0 {
countDown -= 1
}

61. @genehack › Intro to Swift › TPC 2017
Flow Control
var countDown = 5
while countDown > 0 {
countDown -= 1
}

62. @genehack › Intro to Swift › TPC 2017
Flow Control
var countUp = 0
repeat {
countUp++
} while countUp < 5

63. @genehack › Intro to Swift › TPC 2017
Flow Control
var countUp = 0
repeat {
countUp++
} while countUp < 5

64. @genehack › Intro to Swift › TPC 2017
Flow Control
var countUp = 0
repeat {
countUp += 1
} while countUp < 5

65. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = 2
switch sample {
case 0:
print("Is 0")
case 2:
print("Is 2")
default: // mandatory when cases not exclusive
print("Not 0 or 2, is it.")
}

66. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = 2
switch sample {
case 0:
print("Is 0")
case 2:
print("Is 2")
default: // mandatory when cases not exclusive
print("Not 0 or 2, is it.")
}

67. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = 2
switch sample {
case 0:
print("Is 0")
case 2:
print("Is 2")
default: // mandatory when cases not exclusive
print("Not 0 or 2, is it.")
}

68. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = 2
switch sample {
case 0:
print("Is 0")
case 2:
print("Is 2")
default: // mandatory when cases not exclusive
print("Not 0 or 2, is it.")
}
No fallthru by default!

69. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = 2
switch sample {
case 0:
print("Is 0")
case 2:
print("Is 2")
default: // mandatory when cases not exclusive
print("Not 0 or 2, is it.")
}

70. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = "foo"
switch sample {
case "foo":
print("Is foo")
case "bar":
print("Is bar")
default: // mandatory when cases not exclusive
print("Not foo or bar, is it.")
}

71. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = "foo"
switch sample {
case "foo":
print("Is foo")
case "bar":
print("Is bar")
default: // mandatory when cases not exclusive
print("Not foo or bar, is it.")
}

72. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 2):
print("Is foo, 2")
case ("bar", _):
print("Is bar")
default: // mandatory when cases not exclusive
print(" ¯_(ツ)_/¯ ")
}

73. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 2):
print("Is foo, 2")
case ("bar", _):
print("Is bar")
default: // mandatory when cases not exclusive
print(" ¯_(ツ)_/¯ ")
}

74. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 2):
print("Is foo, 2")
case ("bar", _):
print("Is bar")
default: // mandatory when cases not exclusive
print(" ¯_(ツ)_/¯ ")
}

75. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 2):
print("Is foo, 2")
case ("bar", _):
print("Is bar")
default: // mandatory when cases not exclusive
print(" ¯_(ツ)_/¯ ")
}

76. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 3):
print("Is foo, 3")
case (let one, let two):
print("Is (one) and (two)")
}

77. @genehack › Intro to Swift › TPC 2017
Flow Control
let sample = ("foo", 2)
switch sample {
case ("foo", 3):
print("Is foo, 3")
case (let one, let two):
print("Is (one) and (two)")
}

78. @genehack › Intro to Swift › TPC 2017
Strings
var myString = "this is a string"
if myString.isEmpty {
// do something
}
myString += "and this is a longer string"

79. @genehack › Intro to Swift › TPC 2017
Strings
var myString = "this is a string"
if myString.isEmpty {
// do something
}
myString += "and this is a longer string"

80. @genehack › Intro to Swift › TPC 2017
Strings
var myString = "this is a string"
if myString.isEmpty {
// do something
}
myString += "and this is a longer string"

81. Swift is very strongly typed.

82. @genehack › Intro to Swift › TPC 2017
Typing
var foo = 1 // foo is an Int
var bar: Int // bar is an uninit'd Int
var baz = Int()
if baz is Int {
print("Nice Int you got there")
}

83. @genehack › Intro to Swift › TPC 2017
Typing
var foo = 1 // foo is an Int
var bar: Int // bar is an uninit'd Int
var baz = Int()
if baz is Int {
print("Nice Int you got there")
}

84. @genehack › Intro to Swift › TPC 2017
Typing
var foo = 1 // foo is an Int
var bar: Int // bar is an uninit'd Int
var baz = Int()
if baz is Int {
print("Nice Int you got there")
}

85. @genehack › Intro to Swift › TPC 2017
Typing
var foo = 1 // foo is an Int
var bar: Int // bar is an uninit'd Int
var baz = Int()
if baz is Int {
print("Nice Int you got there")
}

86. @genehack › Intro to Swift › TPC 2017
Typing
var foo = 1 // foo is an Int
var bar: Int // bar is an uninit'd Int
var baz = Int()
if baz is Int {
print("Nice Int you got there")
}

87. @genehack › Intro to Swift › TPC 2017
Casts
var foo = 1 // foo is an Int
var bar = String(foo) // "1"
var maybeBaz = stringishThing as? String
// maybeBaz is an optionally typed String
var forceBaz = stringishThing as! String

88. @genehack › Intro to Swift › TPC 2017
Casts
var foo = 1 // foo is an Int
var bar = String(foo) // "1"
var maybeBaz = stringishThing as? String
// maybeBaz is an optionally typed String
var forceBaz = stringishThing as! String

89. @genehack › Intro to Swift › TPC 2017
Casts
var foo = 1 // foo is an Int
var bar = String(foo) // "1"
var maybeBaz = stringishThing as? String
// maybeBaz is an optionally typed String
var forceBaz = stringishThing as! String

90. @genehack › Intro to Swift › TPC 2017
Casts
var foo = 1 // foo is an Int
var bar = String(foo) // "1"
var maybeBaz = stringishThing as? String
// maybeBaz is an optionally typed String
var forceBaz = stringishThing as! String

91. @genehack › Intro to Swift › TPC 2017
Optional Types
// When a variable may not have a value
var bar: Int?
// test
if bar != nil {
// has a value
}

92. @genehack › Intro to Swift › TPC 2017
Optional Types
// When a variable may not have a value
var bar: Int?
// test
if bar != nil {
// has a value
}

93. @genehack › Intro to Swift › TPC 2017
Optional Types
// When a variable may not have a value
var bar: Int?
// test
if bar != nil {
// has a value
}

94. @genehack › Intro to Swift › TPC 2017
Optional Types
// unwrap the value to use
if bar != nil {
bar! += 2
}
// unwrapping nil --> runtime exception!

95. @genehack › Intro to Swift › TPC 2017
Optional Types
// unwrap the value to use
if bar != nil {
bar! += 2
}
// unwrapping nil --> runtime exception!

96. @genehack › Intro to Swift › TPC 2017
Optional Types
// unwrap the value to use
if bar != nil {
bar! += 2
}
// unwrapping nil --> runtime exception!

97. @genehack › Intro to Swift › TPC 2017
if-let
var bar: Int?
if let foo = bar {
// bar had a value &
// foo now has that unwrapped value
}
else {
// bar was nil
}

98. @genehack › Intro to Swift › TPC 2017
if-let
var bar: Int?
if let foo = bar {
// bar had a value &
// foo now has that unwrapped value
}
else {
// bar was nil
}

99. @genehack › Intro to Swift › TPC 2017
if-let
var bar: Int?
if let foo = bar {
// bar had a value &
// foo now has that unwrapped value
}
else {
// bar was nil
}

100. @genehack › Intro to Swift › TPC 2017
if-var
var bar: Int?
if var foo = bar {
// bar had a value &
// foo now has that unwrapped value &
// foo is mutable
foo += 1
}
else {
// bar was nil
}

101. @genehack › Intro to Swift › TPC 2017
if-var
var bar: Int?
if var foo = bar {
// bar had a value &
// foo now has that unwrapped value &
// foo is mutable
foo += 1
}
else {
// bar was nil
}

102. @genehack › Intro to Swift › TPC 2017
if-var
var bar: Int?
if var foo = bar {
// bar had a value &
// foo now has that unwrapped value &
// foo is mutable
foo += 1
}
else {
// bar was nil
}

103. Types of Values

104. @genehack › Intro to Swift › TPC 2017
Tuples
let tuple = ("foo", 42)
let first = tuple.0 // "foo"
let labeledTuple = (one: "foo", two: 42)
let second = labeledTuple.two // 42

105. @genehack › Intro to Swift › TPC 2017
Tuples
let tuple = ("foo", 42)
let first = tuple.0 // "foo"
let labeledTuple = (one: "foo", two: 42)
let second = labeledTuple.two // 42

106. @genehack › Intro to Swift › TPC 2017
Tuples
let tuple = ("foo", 42)
let first = tuple.0 // "foo"
let labeledTuple = (one: "foo", two: 42)
let second = labeledTuple.two // 42

107. @genehack › Intro to Swift › TPC 2017
Tuples
let tuple = ("foo", 42)
let first = tuple.0 // "foo"
let labeledTuple = (one: "foo", two: 42)
let second = labeledTuple.two // 42

108. @genehack › Intro to Swift › TPC 2017
Tuples
let tuple = ("foo", 42)
let first = tuple.0 // "foo"
let labeledTuple = (one: "foo", two: 42)
let second = labeledTuple.two // 42

109. @genehack › Intro to Swift › TPC 2017
Arrays
let nums = [1, 2, 3]
var strs : [String]
// _can_ mix & match
let mixed = [1, "foo"]
// but you probably shouldn't
// in Swift 3+ this is a compile
// error unless specifically
// type-annotated
let mixed: [Any] = [1, "foo"]

110. @genehack › Intro to Swift › TPC 2017
Arrays
let nums = [1, 2, 3]
var strs : [String]
// _can_ mix & match
let mixed = [1, "foo"]
// but you probably shouldn't
// in Swift 3+ this is a compile
// error unless specifically
// type-annotated
let mixed: [Any] = [1, "foo"]

111. @genehack › Intro to Swift › TPC 2017
Arrays
let nums = [1, 2, 3]
var strs : [String]
// _can_ mix & match
let mixed = [1, "foo"]
// but you probably shouldn't
// in Swift 3+ this is a compile
// error unless specifically
// type-annotated
let mixed: [Any] = [1, "foo"]

112. @genehack › Intro to Swift › TPC 2017
Arrays
let nums = [1, 2, 3]
var strs : [String]
// _can_ mix & match
let mixed = [1, "foo"]
// but you probably shouldn't
// in Swift 3+ this is a compile
// error unless specifically
// type-annotated
let mixed: [Any] = [1, "foo"]

113. @genehack › Intro to Swift › TPC 2017
Arrays
let nums = [1, 2, 3]
var strs : [String]
// _can_ mix & match
let mixed = [1, "foo"]
// but you probably shouldn't
// in Swift 3+ this is a compile
// error unless specifically
// type-annotated
let mixed: [Any] = [1, "foo"]

114. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": "Virginia",
]
// capitalCityStates has type
// [String:String]

115. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": "Virginia",
]
// capitalCityStates has type
// [String:String]

116. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": "Virginia",
]
// capitalCityStates has type
// [String:String]

117. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": 2,
]
// capitalCityStates must be
// annotated with type
// [String:Any]

118. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": 2,
]
// capitalCityStates must be
// annotated with type
// [String:Any]

119. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates = [
"Salem": "Oregon",
"Richmond": 2,
]
// capitalCityStates must be
// annotated with type
// [String:Any]

120. @genehack › Intro to Swift › TPC 2017
Dictionary
let capitalCityStates: [String:Any] = [
"Salem": "Oregon",
"Richmond": 2,
]
// capitalCityStates must be
// annotated with type [String:Any]

121. @genehack › Intro to Swift › TPC 2017
Sets
var petSet :Set = [ "cat", "dog",
"fish", "dog"]
petSet.count // returns 3

122. @genehack › Intro to Swift › TPC 2017
Sets
var petSet :Set = [ "cat", "dog",
"fish", "dog"]
petSet.count // returns 3

123. @genehack › Intro to Swift › TPC 2017
Sets
var petSet :Set = [ "cat", "dog",
"fish", "dog"]
petSet.count // returns 3

124. @genehack › Intro to Swift › TPC 2017
Sets
var petSet :Set = [ "cat", "dog",
"fish", "dog"]
petSet.count // returns 3

125. Functions

126. @genehack › Intro to Swift › TPC 2017
Functions
func obExample () {
print("Hello, Perl!")
}
// call like:
obExample()

127. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String) {
print("Hello, (who)!")
}
// call like
obExample(who: "The Perl Conference")

128. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String) {
print("Hello, (who)!")
}
// call like
obExample(who: "The Perl Conference")

129. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String) {
print("Hello, (who)!")
}
// call like
obExample(who: "The Perl Conference")

130. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String) -> String {
return "Hello, (who)!"
}
// call like
let greets = obExample("TPC")
// greets == "Hello, TPC"

131. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String) -> String {
return "Hello, (who)!"
}
// call like
let greets = obExample("TPC")
// greets == "Hello, TPC"

132. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String = "Swift")
-> String {
return "Hello, (who)!"
}
// call like
let greets = obExample(who:"Perl")
// "Hello, Perl!"
let defGreets = obExample()
// "Hello, Swift!"

133. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String = "Swift")
-> String {
return "Hello, (who)!"
}
// call like
let greets = obExample(who:"Perl")
// "Hello, Perl!"
let defGreets = obExample()
// "Hello, Swift!"

134. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String = "Swift")
-> String {
return "Hello, (who)!"
}
// call like
let greets = obExample(who:"Perl")
// "Hello, Perl!"
let defGreets = obExample()
// "Hello, Swift!"

135. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (who :String = "Swift")
-> String {
return "Hello, (who)!"
}
// call like
let greets = obExample(who:"Perl")
// "Hello, Perl!"
let defGreets = obExample()
// "Hello, Swift!"

136. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
who them :String = "Perl") {
print("(what), (them)!")
}
// call like
obExample(what: "bye") // "bye, Perl!"
obExample(what: "bye", who: "Felicia") // "bye, Felicia!"

137. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
who them :String = "Perl") {
print("(what), (them)!")
}
// call like
obExample(what: "bye") // "bye, Perl!"
obExample(what: "bye", who: "Felicia") // "bye, Felicia!"

138. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
who them :String = "Perl") {
print("(what), (them)!")
}
// call like
obExample(what: "bye") // "bye, Perl!"
obExample(what: "bye", who: "Felicia") // "bye, Felicia!"

139. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
who them :String = "Perl") {
print("(what), (them)!")
}
// call like
obExample(what: "bye") // "bye, Perl!"
obExample(what: "bye", who: "Felicia") // "bye, Felicia!"

140. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
who them :String = "Perl") {
print("(what), (them)!")
}
// call like
obExample(what: "bye") // "bye, Perl!"
obExample(what: "bye", who: "Felicia") // "bye, Felicia!"

141. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

142. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

143. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

144. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

145. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

146. @genehack › Intro to Swift › TPC 2017
Functions
func obExample (what :String = "Hello",
_ who :String = "Perl") {
print "(what), (who)!"
}
// call like
obExample(what: "bye") // "bye, Salem!"
obExample(what: "bye", who:"Felicia") // COMPILE ERROR
obExample(what: "bye", "Felicia") // "bye, Felicia!"

147. @genehack › Intro to Swift › TPC 2017
Functions
func variadiacExample (nums: Int...) {
// do something with nums
// nums is Array[Int]
}

148. @genehack › Intro to Swift › TPC 2017
Functions
func variadiacExample (nums: Int...) {
// do something with nums
// nums is Array[Int]
}

149. Functions are first-class citizens

150. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
var sorted = numbers.sorted(by:{
(n1: Int, n2: Int) -> Bool in return n2 > n1
})
// sorted = [1, 2, 13, 32, 56, 120]

151. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
var sorted = numbers.sorted(by:{
(n1: Int, n2: Int) -> Bool in return n2 > n1
})
// sorted = [1, 2, 13, 32, 56, 120]

152. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
var sorted = numbers.sorted(by:{
(n1: Int, n2: Int) -> Bool in return n2 > n1
})
// sorted = [1, 2, 13, 32, 56, 120]

153. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
var sorted = numbers.sorted(by:{
(n1: Int, n2: Int) -> Bool in return n2 > n1
})
// sorted = [1, 2, 13, 32, 56, 120]
This is already the func sig for sort!

154. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// inferred param & return types
var sorted = numbers.sorted(by: {n1, n2 in return n2 > n1})
// sorted = [1, 2, 13, 32, 56, 120]

155. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// inferred param & return types
var sorted = numbers.sorted(by: {n1, n2 in return n2 > n1})
// sorted = [1, 2, 13, 32, 56, 120]

156. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// positionally named parameters
var sorted = numbers.sorted(by: {return $0 > $1})
// sorted = [1, 2, 13, 32, 56, 120]

157. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// positionally named parameters
var sorted = numbers.sorted(by: {return $0 > $1})
// sorted = [1, 2, 13, 32, 56, 120]

158. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// when closure is last param,
// param name & parens optional
var sorted = numbers.sorted { $0 > $1 }
// sorted = [1, 2, 13, 32, 56, 120]

159. @genehack › Intro to Swift › TPC 2017
Closures
let numbers = [2,1,56,32,120,13]
// when closure is last param,
// param name & parens optional
var sorted = numbers.sorted { $0 > $1 }
// sorted = [1, 2, 13, 32, 56, 120]

160. OOP is also
well supported

161. @genehack › Intro to Swift › TPC 2017
Classes
class Dog {
}

162. @genehack › Intro to Swift › TPC 2017
Properties
class Dog {
var name: String
let noise = "WOOF!"
}

163. @genehack › Intro to Swift › TPC 2017
Properties
class Dog {
var name: String
let noise = "WOOF!"
}

164. @genehack › Intro to Swift › TPC 2017
Properties
class Dog {
var name: String
let noise = "WOOF!"
}
Class 'Dog' has no initializers

165. @genehack › Intro to Swift › TPC 2017
Properties
class Dog {
var name: String?
let noise = "WOOF!"
}

166. @genehack › Intro to Swift › TPC 2017
Properties
class Dog {
var name: String?
let noise = "WOOF!"
}

167. @genehack › Intro to Swift › TPC 2017
Initializers
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
}

168. @genehack › Intro to Swift › TPC 2017
Initializers
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
}

169. @genehack › Intro to Swift › TPC 2017
Initializers
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
}

170. @genehack › Intro to Swift › TPC 2017
Deinitializers
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
deinit () {
// do any cleanup here
}
}

171. @genehack › Intro to Swift › TPC 2017
Deinitializers
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
deinit () {
// do any cleanup here
}
}

172. @genehack › Intro to Swift › TPC 2017
Methods
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
func speak () -> String {
return self.noise
}
}

173. @genehack › Intro to Swift › TPC 2017
Methods
class Dog {
var name: String
let noise = "WOOF"
init (name: String) {
self.name = name
}
func speak () -> String {
return self.noise
}
}

174. @genehack › Intro to Swift › TPC 2017
Using Objects
let sammy = Dog(name: "Sammy");
// sammy is Dog
print(sammy.name) // prints "Sammyn"
print(sammy.speak()) // prints "WOOF!n"
sammy.name = "Buster" // works b/c prop is var

175. @genehack › Intro to Swift › TPC 2017
Using Objects
let sammy = Dog(name: "Sammy");
// sammy is Dog
print(sammy.name) // prints "Sammyn"
print(sammy.speak()) // prints "WOOF!n"
sammy.name = "Buster" // works b/c prop is var

176. @genehack › Intro to Swift › TPC 2017
Using Objects
let sammy = Dog(name: "Sammy");
// sammy is Dog
print(sammy.name) // prints "Sammyn"
print(sammy.speak()) // prints "WOOF!n"
sammy.name = "Buster" // works b/c prop is var

177. @genehack › Intro to Swift › TPC 2017
Using Objects
let sammy = Dog(name: "Sammy");
// sammy is Dog
print(sammy.name) // prints "Sammyn"
print(sammy.speak()) // prints "WOOF!n"
sammy.name = "Buster" // works b/c prop is var

178. @genehack › Intro to Swift › TPC 2017
Using Objects
let sammy = Dog(name: "Sammy");
// sammy is Dog
print(sammy.name) // prints "Sammyn"
print(sammy.speak()) // prints "WOOF!n"
sammy.name = "Buster" // works b/c prop is var

179. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set {
// this is horrible, don't do this
self.birthYear = currentYear - newValue
}
}
}

180. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set {
// this is horrible, don't do this
self.birthYear = currentYear - newValue
}
}
}

181. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set {
// this is horrible, don't do this
self.birthYear = currentYear - newValue
}
}
}

182. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set {
// this is horrible, don't do this
self.birthYear = currentYear - newValue
}
}
}

183. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set (age) {
// this is horrible, don't do this
self.birthYear = currentYear - age
}
}
}

184. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set (age) {
// this is horrible, don't do this
self.birthYear = currentYear - age
}
}
}

185. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
get {
return currentYear - self.birthYear
}
set {
// this is horrible, don't do this
self.birthYear = currentYear - age
}
}
}

186. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
willSet {
// runs before property value changes
}
didSet {
// runs after property value changes
}
}
}

187. @genehack › Intro to Swift › TPC 2017
Computed Properties
class Dog {
var age :Int {
willSet {
// runs before property value changes
}
didSet {
// runs after property value changes
}
}
}

188. Inheritance

189. @genehack › Intro to Swift › TPC 2017
Inheritance
class Animal {
}
class Dog : Animal {
}

190. @genehack › Intro to Swift › TPC 2017
Inheritance
class Animal {
}
class Dog : Animal {
}

191. @genehack › Intro to Swift › TPC 2017
Inheritance
class Animal {
let name: String
init (name: name) {
self.name = name
}
}
class Dog : Animal {
override init (name: name) {
super.init(name: name)
}
}

192. @genehack › Intro to Swift › TPC 2017
Inheritance
class Animal {
let name: String
init (name: name) {
self.name = name
}
}
class Dog : Animal {
override init (name: name) {
super.init(name: name)
}
}

193. @genehack › Intro to Swift › TPC 2017
Inheritance
class Animal {
let name: String
init (name: name) {
self.name = name
}
}
class Dog : Animal {
override init (name: name) {
super.init(name: name)
}
}

194. @genehack › Intro to Swift › TPC 2017
Overrides
class Animal {
func speak() { ... }
}
class Dog : Animal {
override func speak () { ... }
}

195. @genehack › Intro to Swift › TPC 2017
Overrides
class Animal {
func speak() { ... }
}
class Dog : Animal {
override func speak () { ... }
}

196. Structs & Enumerations

197. @genehack › Intro to Swift › TPC 2017
Structs
struct Animal {
var name: String
var noise: String
init (name: String, makes: String) {
self.name = name
noise = makes
}
func speak () -> String {
return noise
}
}

198. @genehack › Intro to Swift › TPC 2017
Structs
struct Animal {
var name: String
var noise: String
init (name: String, makes: String) {
self.name = name
noise = makes
}
func speak () -> String {
return noise
}
}

199. @genehack › Intro to Swift › TPC 2017
Structs
struct Animal {
var name: String
var noise: String
init (name: String, makes: String) {
self.name = name
noise = makes
}
func speak () -> String {
return noise
}
}

200. @genehack › Intro to Swift › TPC 2017
Structs
struct Animal {
var name: String
var noise: String
init (name: String, makes: String) {
self.name = name
noise = makes
}
func speak () -> String {
return noise
}
}

201. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
}
var conf = OpenSourceConfs.TPC
// conf is type OpenSourceConfs

202. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
}
var conf = OpenSourceConfs.TPC
// conf is type OpenSourceConfs

203. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
}
var conf = OpenSourceConfs.TPC
// conf is type OpenSourceConfs

204. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
}
var conf = OpenSourceConfs.TPC
// conf is type OpenSourceConfs

205. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs :Int {
case TPC = 1
case YAPC
}
var conf = OpenSourceConfs.YAPC
// conf is type OpenSourceConfs
conf.rawValue // 2

206. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs :Int {
case TPC = 1
case YAPC
}
var conf = OpenSourceConfs.YAPC
// conf is type OpenSourceConfs
conf.rawValue // 2

207. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs :Int {
case TPC = 1
case YAPC
}
var conf = OpenSourceConfs.YAPC
// conf is type OpenSourceConfs
conf.rawValue // 2

208. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs :Int {
case TPC = 1
case YAPC
}
var conf = OpenSourceConfs.YAPC
// conf is type OpenSourceConfs
conf.rawValue // 2

209. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
func describe() -> String {
switch self {
case .TPC:
return "hello virginia!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC
conf.describe()

210. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
func describe() -> String {
switch self {
case .TPC:
return "hello virginia!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC
conf.describe()

211. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
func describe() -> String {
switch self {
case .TPC:
return "hello virginia!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC
conf.describe()

212. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC
case YAPC
func describe() -> String {
switch self {
case .TPC:
return "hello virginia!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC
conf.describe()

213. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC(let location):
return "hello (location)!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC("DC")
conf.describe()

214. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC(let location):
return "hello (location)!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC("DC")
conf.describe()

215. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC(let location):
return "hello (location)!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC("DC")
conf.describe()

216. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC(let location):
return "hello (location)!"
case .YAPC:
return "I thought YAPC was dead"
}
}
}
var conf = OpenSourceConfs.TPC("DC")
conf.describe()

217. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC (let location):
return "hello (location)!"
case .YAPC(location)
return "I thought YAPC was dead"
}
}
}
var tpc2017 = OpenSourceConfs.TPC("DC")
var tpc2018 = OpenSourceConfs.TPC("Pittsurgh?")

218. @genehack › Intro to Swift › TPC 2017
Enumerations
enum OpenSourceConfs {
case TPC(String)
case YAPC
func describe() -> String {
switch self {
case .TPC (let location):
return "hello (location)!"
case .YAPC(location)
return "I thought YAPC was dead"
}
}
}
var tpc2017 = OpenSourceConfs.TPC("DC")
var tpc2018 = OpenSourceConfs.TPC("Pittsurgh?")

219. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
}

220. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
}

221. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
}

222. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
}

223. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

224. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

225. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

226. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

227. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

228. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

229. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker {
var noise: String { get }
func talk () -> String
mutating func mute()
}
class Dog: Talker {
var noise: String
init (noise: String) {
self.noise = noise
}
func talk () -> String {
return noise
}
func mute () {
noise = ""
}
}

230. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker { ... }
class Dog: Talker { ... }
class Fish { ... }
var sammy: Talker
sammy = Dog(noise: "WOOF!")
sammy = Fish() // compile error

231. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker { ... }
class Dog: Talker { ... }
class Fish { ... }
var sammy: Talker
sammy = Dog(noise: "WOOF!")
sammy = Fish() // compile error

232. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker { ... }
class Dog: Talker { ... }
class Fish { ... }
var sammy: Talker
sammy = Dog(noise: "WOOF!")
sammy = Fish() // compile error

233. @genehack › Intro to Swift › TPC 2017
Protocols
protocol Talker { ... }
class Dog: Talker { ... }
class Fish { ... }
var sammy: Talker
sammy = Dog(noise: "WOOF!")
sammy = Fish() // compile error

234. @genehack › Intro to Swift › TPC 2017
Extensions
extension Int {
func squared () -> Int {
return self * self
}
}
let foo = 2
print(foo.squared()) // 4
print(foo.squared().squared()) // 16

235. @genehack › Intro to Swift › TPC 2017
Extensions
extension Int {
func squared () -> Int {
return self * self
}
}
let foo = 2
print(foo.squared()) // 4
print(foo.squared().squared()) // 16

236. @genehack › Intro to Swift › TPC 2017
Extensions
extension Int {
func squared () -> Int {
return self * self
}
}
let foo = 2
print(foo.squared()) // 4
print(foo.squared().squared()) // 16

237. @genehack › Intro to Swift › TPC 2017
Extensions
extension Int {
func squared () -> Int {
return self * self
}
}
let foo = 2
print(foo.squared()) // 4
print(foo.squared().squared()) // 16

238. Exceptions & Error Handling

239. @genehack › Intro to Swift › TPC 2017
Exceptions
enum TalkErrors: Error {
case TooShort
case TooLong
case TooBoring
}
func giveATalk (talk: String) throws -> String {
if talk == "boring" {
throw TalkErrors.TooBoring
}
return "talk!"
}

240. @genehack › Intro to Swift › TPC 2017
Exceptions
enum TalkErrors: Error {
case TooShort
case TooLong
case TooBoring
}
func giveATalk (talk: String) throws -> String {
if talk == "boring" {
throw TalkErrors.TooBoring
}
return "talk!"
}

241. @genehack › Intro to Swift › TPC 2017
Exceptions
enum TalkErrors: Error {
case TooShort
case TooLong
case TooBoring
}
func giveATalk (talk: String) throws -> String {
if talk == "boring" {
throw TalkErrors.TooBoring
}
return "talk!"
}

242. @genehack › Intro to Swift › TPC 2017
Exceptions
enum TalkErrors: Error {
case TooShort
case TooLong
case TooBoring
}
func giveATalk (talk: String) throws -> String {
if talk == "boring" {
throw TalkErrors.TooBoring
}
return "talk!"
}

243. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "boring")
print(thisTalk)
}
catch {
print(error)
}

244. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "boring")
print(thisTalk)
}
catch {
print(error)
}

245. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "boring")
print(thisTalk)
}
catch {
print(error)
}

246. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "boring")
print(thisTalk)
}
catch {
print(error)
}

247. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "fine")
print(thisTalk)
}
catch TalkErrors.TooLong {
print("shut up already")
}
catch let talkError as TalkErrors {
print("Talk error: (talkError).")
}
catch {
print (error)
}

248. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "fine")
print(thisTalk)
}
catch TalkErrors.TooLong {
print("shut up already")
}
catch let talkError as TalkErrors {
print("Talk error: (talkError).")
}
catch {
print (error)
}

249. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "fine")
print(thisTalk)
}
catch TalkErrors.TooLong {
print("shut up already")
}
catch let talkError as TalkErrors {
print("Talk error: (talkError).")
}
catch {
print (error)
}

250. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "fine")
print(thisTalk)
}
catch TalkErrors.TooLong {
print("shut up already")
}
catch let talkError as TalkErrors {
print("Talk error: (talkError).")
}
catch {
print (error)
}

251. @genehack › Intro to Swift › TPC 2017
Exceptions
do {
let thisTalk = try giveATalk(talk: "fine")
print(thisTalk)
}
catch TalkErrors.TooLong {
print("shut up already")
}
catch let talkError as TalkErrors {
print("Talk error: (talkError).")
}
catch {
print (error)
}

252. @genehack › Intro to Swift › TPC 2017
Exceptions
// silently discards error
let thisTalk = try? giveATalk(talk:"fine")
// thisTalk isa String?

253. @genehack › Intro to Swift › TPC 2017
Exceptions
// silently discards error
let thisTalk = try? giveATalk(talk:"fine")
// thisTalk isa String?

254. @genehack › Intro to Swift › TPC 2017
Exceptions
// silently discards error
let thisTalk = try? giveATalk(talk:"fine")
// thisTalk isa String?

255. @genehack › Intro to Swift › TPC 2017
Defer
func needsMuchSetupAndTearDown () {
// do the setup here, open files, etc.
defer {
// and do the cleanup here,
// right next to set up
}
// other code here.
}

256. @genehack › Intro to Swift › TPC 2017
Defer
func needsMuchSetupAndTearDown () {
// do the setup here, open files, etc.
defer {
// and do the cleanup here,
// right next to set up
}
// other code here.
}

257. Workspaces

258. Ill-advised
live
demo
time!

259. Ill-advised
live
demo
time!

262. https://developer.apple.com/swift

264. THANKS!

266. questions?