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༗ཧΫϥεͷ͢͢Ί
2017/08/08
Swift/Kotlin߹ಉษڧձ
@ΦΠγοΫευοτେגࣜձࣾ
Koishi
1 Koichiro Oishi, 2017/08/08
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ࣗݾհ
େੴ ߂Ұ
γεςϜɾΞφϥΠζגࣜձࣾ
iOSΞϓϦ։ൃऀ
ΞΧϯτؔ࿈
* @mego_
* koishi
2 Koichiro Oishi, 2017/08/08
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ίϯςΩετ
iOSΞϓϦΤϯδχΞͰ͢ɻ
Objective-CͱSwiftࣝ͋Δ(͋Δఔ)
JavaͳΜͱͳͬͯ͘Δɻ
Kotlinೖத !
3 Koichiro Oishi, 2017/08/08
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ࢀߟจݙ
Swift
࣮ફೖ
※ஶऀͷ1ਓɺੴ͞Μ͔Βα
ΠϯΒ͍·ͨ͠ɻ
4 Koichiro Oishi, 2017/08/08
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ࢀߟจݙ
Kotlin
ελʔτϒοΫ
௨শʮ͜ຊʯ
※ஶऀͷͨΖ͏͞Μ͔ΒαΠϯ
Β͍·ͨ͠ɻ
5 Koichiro Oishi, 2017/08/08
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͓
༗ཧΫϥεͷ࣮
6 Koichiro Oishi, 2017/08/08
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ݩωλ
ʮKotlin ελʔτϒοΫʯ
• p.27ʙp.40
• ୈ3ষ KotlinΨΠυπΞʔ
• KotlinͷεϚʔτͳݴޠ༷͕ѲͰ͖Δ༰
7 Koichiro Oishi, 2017/08/08
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ݩʑͷग़య
Scala
εέʔϥϒϧ
ϓϩάϥϛϯά
• ௨শίοϓຊ
8 Koichiro Oishi, 2017/08/08
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༗ཧΫϥε
• ༗ཧͱࢠ(numerator)ͱ(denominator)Ͱ
දݱ͢Δ
• ༗ཧ()Λදݱ͢ΔΫϥεRationalͷ࣮
ͦΕͰߦͬͯΈ·͠ΐ͏ʂ
9 Koichiro Oishi, 2017/08/08
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Ϋϥεͷఆٛ(Kotlin)
ࢠͱΛϓϩύςΟͱͯ࣋ͭ͠ΫϥεRational
Λఆٛ͢Δ
class Rational(val numerator: Int, val denominator: Int)
• numeratorͱdenominator͜Ε͚ͩͰϓϩύςΟ
ʹͳΔɻ
• ͪͳΈʹvalఆɺvarม
10 Koichiro Oishi, 2017/08/08
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Ϋϥεͷఆٛ(Swift)
struct Rational {
let numerator: Int
let denominator: Int
}
let rational = Rational(numerator: 1, denominator: 2)
• ϓϩύςΟΛఆٛ͢ΕΠχγϟϥΠβͷҾͱ
ͯͦ͠ͷ··͑Δ
• ͪͳΈʹletఆɺvarม
11 Koichiro Oishi, 2017/08/08
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ϝιουͷఆٛ(Kotlin)
print(rational)ͨ͠ࡍʹͷදࣔΛͰ͖ΔΑ͏ʹ͢Δ
Rational@279f2327 Ͱͳ͘ 1/2 ͳͲͱ͍ͨ͠
class Rational(val numerator: Int, val denominator: Int) {
override fun toString(): String = "${numerator}/${denominator}"
}
• toString()ΛΦʔόϥΠυ͢Δ
12 Koichiro Oishi, 2017/08/08
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ϝιουͷఆٛ(Swift)
extension Rational: CustomStringConvertible {
var description: String {
return "\(numerator)/\(denominator)"
}
}
• CustomStringConvertibleϓϩτίϧʹ४ڌͨ͠
extensionͰdescriptionϓϩύςΟΛ࣮
13 Koichiro Oishi, 2017/08/08
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ΠχγϟϥΠβ(Kotlin)
ʹ0͕ೖ͞Εͨ߹Τϥʔͱ͢ΔͨΊΠχ
γϟϥΠβͰ࣮͢Δ
class Rational(val numerator: Int, val denominator: Int) {
init {
require(denominator != 0, {"denominator must not be null"})
}
override fun toString(): String = "${numerator}/${denominator}"
}
• ؔrequireͰ͕0Ҏ֎Ͱ͋Δ͜ͱΛཁٻɺ
ͨ͠߹ΤϥʔΛ͛Δ
14 Koichiro Oishi, 2017/08/08
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ΠχγϟϥΠβ(Swift ͦͷ1)
ࣦഊͨ͠Βྫ֎Λ͛Δύλʔϯ
init(numerator: Int, denominator: Int) throws {
if denominator == 0 {
throw NSError(domain: "denominator must not be null",
code: -1, userInfo: nil)
}
self.numerator = numerator
self.denominator = denominator
}
• ࠓճͪ͜ΒΛྫͰਐΊ·͢
15 Koichiro Oishi, 2017/08/08
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ΠχγϟϥΠβ(Swift ͦͷ2)
ࣦഊͨ͠ΒnilΛฦ͢ύλʔϯ
init?(numerator: Int, denominator: Int) {
if denominator == 0 {
return nil
}
self.numerator = numerator
self.denominator = denominator
}
• Γ͕Optionalܕʹ
• ݺͼग़͠ଆͰUnwrap͕ඞཁ
16 Koichiro Oishi, 2017/08/08
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ඇެ։ϓϩύςΟϝιου(Kotlin)
࠷େެ(greatest common divisor)ΛٻΊ͍ͨ
ྫ͑ɺ4/6ͷ߹2/3ͱ͍ͨ͠ɻ
tailrec private fun gcd(a: Int, b: Int): Int =
if (b == 0) a
else gcd(b, a% b)
• private͚ͭΕϓϥΠϕʔτ
• ͞Βʹ࠶ؼؔʹtailrecΛ͚ͭΔ
17 Koichiro Oishi, 2017/08/08
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ඇެ։ϓϩύςΟϝιου(Swift ͦͷ1)
ಉ͘͡࠷େެ(greatest common divisor)ΛٻΊΔ
ϝιου
private func gcd(a: Int, b: Int) -> Int {
return b == 0 ? a : gcd(a: b, b: a % b)
}
• ϩδοΫࣗମಉ͡
18 Koichiro Oishi, 2017/08/08
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ඇެ։ϓϩύςΟϝιου(Swift ͦͷ2)
extension Rational: CustomStringConvertible {
var description: String {
let g = gcd(a: abs(numerator), b: abs(denominator))
return "\(numerator/g)/\(denominator/g)"
}
private func gcd(a: Int, b: Int) -> Int {
return b == 0 ? a : gcd(a: b, b: a % b)
}
}
࣮લˠ10/6
࣮ޙˠ5/3
19 Koichiro Oishi, 2017/08/08
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ԋࢉࢠΦʔόʔϩʔυ(Kotlin ͦͷ1)
ϝιουplusΛՃͯ͠Rationalಉ࢜ͷ͠ࢉΛͰ͖
ΔΑ͏ʹ͢Δ
fun plus(that: Rational): Rational =
Rational(
numerator * that.denominator + that.numerator * denominator,
denominator * that.denominator
)
• rational1.plus(rational2) ͱॻ͚ΔΑ͏ʹͳΔ
20 Koichiro Oishi, 2017/08/08
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ԋࢉࢠΦʔόʔϩʔυ(Kotlin ͦͷ2)
͞Βʹrational1 + ratiolan2 Έ͍ͨʹॻ͖͍ͨ
operator fun plus(that: Rational): Rational =
Rational(
numerator * that.denominator + that.numerator * denominator,
denominator * that.denominator
)
• ԋࢉࢠΦʔόʔϩʔυ = operator overload
Rational(10, 6) + Rational(1, 3)
2/1
ͱͰ͖Δ
21 Koichiro Oishi, 2017/08/08
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ԋࢉࢠΦʔόʔϩʔυ(Swift)
SwiftͰԋࢉࢠΛΦʔόʔϩʔυ͢Δͱ͜͏ͳΔ
static func +(left: Rational, right: Rational) -> Rational {
return try! Rational(
numerator: left.numerator * right.denominator
+ right.numerator * left.denominator,
denominator: left.denominator * right.denominator)
}
22 Koichiro Oishi, 2017/08/08
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ϝιουͷΦʔόʔϩʔυ(Kotlin)
Rational(1, 2) + 1ͷΑ͏ͳܭࢉΛͰ͖ΔΑ͏ʹ͢Δɻ
operator fun plus(n: Int): Rational = Rational(numerator + n * denominator,
denominator)
Rational(10, 6) + 1
8/3
ͱͰ͖ΔΑ͏ʹ
23 Koichiro Oishi, 2017/08/08
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ϝιουͷΦʔόʔϩʔυ(Swift)
static func +(rational: Rational, int: Int) -> Rational {
return try! Rational(numerator: rational.numerator
+ int * rational.denominator,
denominator: rational.denominator)
}
24 Koichiro Oishi, 2017/08/08
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֦ுؔ(Kotlin)
• Intʹର͢Δ֦ுؔͱͯ͠RationalΛҾͱ͢Δ
plusϝιουΛՃ
operator fun Int.plus(r: Rational): Rational = r + this
1 + Rational(10, 6)
8/3
ͱͰ͖ΔΑ͏ʹ
25 Koichiro Oishi, 2017/08/08
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֦ுؔ(Swift)
• +ʹҾͱͯ͠ࠨลInt + ӈลRationalΛ࣮
static func +(left: Int, right: Rational) -> Rational {
return right + left
}
26 Koichiro Oishi, 2017/08/08
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·ͱΊ
ͬͨ͜ͱ
• Ϋϥεͷఆٛ
• ϓϩύςΟɺϝιουɺΠχγϟϥΠβͷఏࣔ
• ؔΦʔόϩʔυ
• طଘͷܕʹϝιουΛՃ(֦ுؔ)
ଞͷݴޠͰ༗ཧΫϥεͷ࣮Λͯ͠ΈΔͱษڧʹͳ
Γͦ͏Ͱ͢Ͷʁ
27 Koichiro Oishi, 2017/08/08
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͝հͨ͠Swiftͷ࣮ྫͪ͜Β
• https:/
/gist.github.com/koishi -> SwiftRational.swift
• https:/
/gist.github.com/koishi/
d54a38e3216aaaf87ac592465adb0695
ποίϛେܴͰ͢
28 Koichiro Oishi, 2017/08/08
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͝੩ௌ͋Γ͕ͱ͏
͍͟͝·ͨ͠ɻ
29 Koichiro Oishi, 2017/08/08