Strings and Characters in Swift Goichi Hirakawa

(Goichi Hirakawa)

@gooichi

OS X / iOS

Objective-CXX

String

String

String

String

String UnicodeUnicode-Correct

Local-Insensitive

Value Type

4Views

Objective-CObjective-C Bridge

Unicode

SwiftUnicode

UTF-8UTF-16UTF-32

==

Swift

Unicode

NSStringAPI

let

Copy-on-Write

4

CharacterView

UnicodeScalarView

UTF16View

UTF8View

Objective-C

NSStringObjective-C

NSStringString

NSStringString1.2

String String

characters: Character

unicodeScalars: UnicodeScalarUnicode

utf16: UTF16.CodeUnitUTF-16

utf8: UTF8.CodeUnitUTF-8

NSStringUTF-16 UTF-16

Unicode Code Point

Unicode; 010FFFF21-bit

Code Unit

bit

UnicodeUnicode Scalar SwiftUnicodeScalar

0D7FFE00010FFFF

UTF-32

Extended Grapheme Cluster SwiftCharacter

1Unicode

Dog

Character D U+0044o

U+006Fg

U+0067

U+203C

U+1F436

Unicode Scalar (UTF-32)

0x44 0x6F 0x67 0x203C 0x1F436

0 1 2 3 4

UTF-16

0x44 0x6F 0x67 0x203C 0xD83D 0xDC36

0 1 2 3 4 5

UTF-8

0x44 0x6F 0x67 0xE2 0x80 0xBC 0xF0 0x9F 0x90 0xB6

0 1 2 3 4 5 6 7 8 9

String Character(s)

UnicodeScalar(s)

UTF16View

UTF8View

Number, Streamable, CustomStringConvertible, CustomDebugStringConvertible, etc

NSString

String

NSString

CJKCJK

==!=

String / Character

Unicode Canonical Equivalent

Unicode

U+00E9 () == U+0065 (e) + U+0301 ( )

Compatibility Equivalent

U+2460 () == U+0031(1)

NSString

-isEqualToString:UTF-16

NSString==-isEqual:-isEqualToString:

compare:Undocumented

(1) Swift let string1 = "\u{E9}" // let string2 = "\u{65}\u{301}" // e + print(string1 == string2) // true

Objective-C let nsString1: NSString = string1 print(nsString1 == string2) // false print(nsString1.isEqualToString(string2)) // false print(nsString1.compare(string2) == NSComparisonResult.OrderedSame) // true

CJKCJK CJK

Unicode

CJK

IBMJIS X 0213

CJK

CJK

(2) let unifiedKanji = "\u{585A}" //

let compatiKanji = "\u{FA10}" //

print(unifiedKanji == compatiKanji) // true

let unifiedKanji = "\u{5D0E}" //

let nonCompatiKanji = "\u{FA11}" //

print(unifiedKanji == nonCompatiKanji) // false

IVS: Ideographic Variation Sequence/Selector

CJK U+585A CJK U+FA10

IVSU+585A U+E0100 1 U+585A U+E0103 2 U+585A U+E0101 1 U+585A U+E0105 2

3 U+585A U+FE01 U+585A U+FE00

1 Adobe-Japan1 2 Hanyo-Denshi 3 UnicodeIVS

(3) CJKCJK let unifiedKanji = "\u{585A}" //

let compatiKanji = "\u{FA10}" //

print(unifiedKanji == compatiKanji) // true

IVSAdobe-Japan1Hanyo-Denshi let adobeKanji = "\u{585A}\u{E0100}" //

let hanyoKanji = "\u{585A}\u{E0103}" //

print(adobeKanji == hanyoKanji) // false

String

NSStringUnicodeSwiftUnicode

Swift 2NSString API