SwiftSyntax で便利を実現する基礎 / How to Use SwiftSyntax for Better Productivity (Japanese version)

SwiftSyntax を使うと、Swift のコード生成や書き換え、静的検査などを実現できます。しかし、SwiftSyntax の使い方はほとんど知られていません。この方法をダイジェストで紹介します。

try! Swift Tokyo 2019
https://www.tryswift.co/events/2019/tokyo/jp/

Transcript

1. 4XJGU4ZOUBYͰ

   ศརΛ࣮ݱ͢Δجૅ
   Kuniwak - DeNA Co.,Ltd.
   2019.03.22 try! Swift Tokyo 2019
   

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2. 2
   Some code will be presented in the slides,

   you can see the slides and the code here:
   ൃදதʹίʔυ͕ग़͖ͯ·͕͢ɺಡΈͮΒ͍৔߹͸

   ҎԼ͔ΒεϥΠυΛ͝ཡ͍ͩ͘͞ɿ
   speakerdeck.com/orgachem
   

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3. "CPVUNF
   

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4. ,VOJXBL
   w ॴଐˠ
   • github.com/Kuniwak
   • qiita.com/Kuniwak
   w ߏจղੳ΍୯ମςετ͕޷෺
   w "QQ$PEF࢖͍
   4
   

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5. ෼ؒͰ఻͍͑ͨ͜ͱ
   

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6. 4XJGU4ZOUBYΛ࢖͏ͱɺ4XJGUͷ

   ੩తݕࠪ΍ίʔυੜ੒Λ؆୯ʹͰ͖Δʂ
   6
   

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7. 4XJGU4ZOUBYͱ͸
   

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8. 4XJGU4ZOUBY͸4XJGUͷެࣜϥΠϒϥϦ
   github.com/apple/swift-syntax
   8
   

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9. 4XJGU4ZOUBYͰ

   Ͱ͖Δ͜ͱ
   

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10. ಡΈॻ͖͠΍͍͢σʔλ
    ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    ಡΈॻ͖͠΍͍͢σʔλΛɺίʔυʹ͢Δ
    
    
    4XJGUͷίʔυ
    ಡΈॻ͖͠΍͍͢σʔλ 4XJGUͷίʔυ
    10
    

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11. ಡΈॻ͖͠΍͍͢σʔλ
    ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    ಡΈॻ͖͠΍͍͢σʔλΛɺίʔυʹ͢Δ
    
    
    4XJGUͷίʔυ
    ಡΈॻ͖͠΍͍͢σʔλ 4XJGUͷίʔυ
    11
    

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12. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    12
    આ໌ʹ࢖͏αϯϓϧίʔυ
    

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13. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    JGจ
    13
    ͜Ε͸ʮJGจʯͱݺ͹ΕΔ
    

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14. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    ৚݅
    14
    JGจ͸ʮ৚݅ʯͱʮෳจʯͰ

    ߏ੒͞Ε͍ͯΔ
    

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15. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ৚݅
    15
    ࠓճͷ৚݅෦෼ʹ͸ɺ

    ʮ0QUJPOଋറ৚݅ʯͱ

    ݺ͹Ε͍ͯΔ΋ͷ͕ೖΔ
    

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16. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ৚݅
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    16
    0QUJPOଋറ৚݅͸ɺ୅ೖઌͷ

    ʮม਺ύλʔϯʯͱ୅ೖ͢Δ஋ͷ

    ʮม਺ࣜʯͰߏ੒͞Ε͍ͯΔ
    

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17. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    if let self = self {}
    17
    ͜ͷΑ͏ʹɺίʔυΛ෼ղͯ͠

    ߏ੒ཁૉΛḷ͍ͬͯ͘ͱɺ

    ίʔυΛʮ໦ߏ଄ʯͱͯ͠

    ѻ͍ͬͯΔ͜ͱʹؾͮ͘
    

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18. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    if let self = self {}
    18
    ෳจ
    JGจ
    ෳจ
    ม਺ύλʔϯ ม਺ࣜ
    0QUJPOଋറ৚݅
    

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19. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    
    if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    JGจ
    ෳจ
    ม਺ύλʔϯ ม਺ࣜ
    ͜ΕΛʮߏจ໦ʯͱΑͿ
    19
    0QUJPOଋറ৚݅
    

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20. 4XJGU4ZOUBYͰ

    ʮߏจ໦ʯΛಡΉ
    

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21. 4XJGU4ZUOBYͰߏจ໦ΛಡΉ
    
    if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    ม਺໊ΛಡΜͰΈΑ͏
    21
    

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22. import SwiftSyntax
    let url = URL(fileURLWithPath: "example.swift")
    let source = try String(contentsOf: url)
    let syntax = try SyntaxParser.parse(source: source)
    4XJGU4ZOUBYͰ
    ಡΈॻ͖͠΍͍͢σʔλʢߏจ໦ʣʹ͢Δ
    4XJGUͷίʔυΛ
    22
    

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23. if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    ifStmt
    4XJGU4ZUOBYͰߏจ໦ΛಡΉ
    
    JGจ·ͰͷऔΓํ͸

    গ͠໘౗ͳͷͰޙड़
    23
    

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24. if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    ifStmt
    .conditions[0]
    .condition
    

    4XJGU4ZUOBYͰߏจ໦ΛಡΉ
    
    24
    

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25. if let self = self {}
    if let self = self {}
    JGจ
    ෳจ
    0QUJPOଋറ
    ม਺ࣜ
    ม਺ύλʔϯ
    if let self = self {}
    "self"
    ifStmt
    .conditions[0]
    .condition
    .pattern

    .identifier
    .text
    4XJGU4ZUOBYͰߏจ໦ΛಡΉ
    
    25
    

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26. let name = ifStmt
    .conditions[0]
    .condition
    .pattern

    .identifier
    .text
    if name == "this" {
    print("Oops!")
    }
    ྫ͑͹ɺif let self = ͷม਺໊͕

    ౷Ұ͞Ε͍ͯͳ͍৔߹ʹܯࠂͰ͖Δ
    ߏจ໦ΛಡΊΕ͹ɺΦϨΦϨ4XJGU-JOU͕ॻ͚Δ
    
    26
    

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27. import SwiftSyntax
    let url = URL(fileURLWithPath: "example.swift")
    let source = try String(contentsOf: url)
    let syntax = try SyntaxParser.parse(source: source)

    let stmts = Array(syntax.statements)

    guard let ifStmt = stmts.first?.item as? IfStmtSyntax else {
    print("If statement not found at the position.")
    return
    }
    JGจ͸গ͠ख͕ؒͩ͜ͷΑ͏ʹऔΕΔɻ࣮ࡍͷߏจ໦ΛEVNQ͢ΔͱΘ͔Δ
    JGจ·ͰͷऔΓํ
    27
    ൃ
    ද
    Ͱ
    ͸
    ল
    ུ
    

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28. ಡΈॻ͖͠΍͍͢ߏจ໦
    ίʔυΛɺಡΈॻ͖͠΍͍͢ߏจ໦ʹ͢Δ
    ಡΈॻ͖͠΍͍͢ߏจ໦Λɺίʔυʹ͢Δ
    
    
    4XJGUͷίʔυ
    ಡΈॻ͖͠΍͍͢σʔλ 4XJGUͷίʔυ
    DONE
    28
    

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29. ίʔυΛɺಡΈॻ͖͠΍͍͢σʔλʹ͢Δ
    ಡΈॻ͖͠΍͍͢ߏจ໦Λɺίʔυʹ͢Δ
    
    
    4XJGUͷίʔυ
    4XJGUͷίʔυ
    ಡΈॻ͖͠΍͍͢ߏจ໦
    ಡΈॻ͖͠΍͍͢ߏจ໦
    DONE
    29
    

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30. if let this = self {}
    4XJGU4ZUOBYͰमਖ਼ͨ͠ίʔυΛੜ੒͢Δ
    
    if let self = self {}
    30
    

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31. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    31
    

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32. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    4XJGU4ZOUBYΛ࢖͏
    32
    

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33. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    4XJGU4ZOUBYͰಡΈॻ͖͠΍͍͢ߏจ໦ʹ͢Δ
    33
    

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34. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    ߏจ໦Λॻ͖׵͑ͯɺ݁ՌΛදࣔ͢Δ
    34
    

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35. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    ߏจ໦Λॻ͖׵͑ΔͨΊͷΫϥε
    35
    

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36. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    ॻ͖׵͍͑ͨߏจ໦ͷWJTJUؔ਺ΛPWFSSJEF͢Δ
    ࠓճ͸JGMFU9ͷ9෦෼͕ର৅

    ʢܕͷ໊લ͸EVNQͰௐ΂ΔͱΘ͔Δʣ
    36
    

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37. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    JGMFU9ͷ9෦෼͕UIJTͳΒॻ͖׵͑Δ
    37
    

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38. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    9෦෼ΛTFMGʹॻ͖׵͑Δ
    38
    

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39. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    39
    

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40. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax)) "if let self= self {}"
    40
    ίʔυΛੜ੒Ͱ͖ͨʂ
    

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41. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax)) "if let self= self {}"
    41
    Α͘ݟΔͱۭന͕

    ফ͑ͯ͠·͍ͬͯΔ
    

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42. import SwiftSyntax
    class RenameRewriter: SyntaxRewriter {
    override func visit(_ node: IdentifierPatternSyntax) -> PatternSyntax {
    if node.identifier.text == "this" {
    var modifiedNode = node
    let originalIdentifier = node.identifier
    modifiedNode.identifier = SyntaxFactory
    .makeIdentifier("self")
    .withTrailingTrivia(originalIdentifier.trailingTrivia)
    return modifiedNode
    }
    return node
    }
    }
    let syntax = try SyntaxParser.parse(source: String(contentsOf: url))
    print(RenameRewriter().visit(syntax))
    TFMGޙͷۭന͕ͳ͘ͳΔ໰୊͸5SJWJBͰௐ੔Ͱ͖Δ
    ൃ
    ද
    Ͱ
    ͸
    ল
    ུ
    42
    

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43. if let this = self {}
    4XJGU4ZUOBYͰमਖ਼ͨ͠ίʔυΛੜ੒͢Δ
    
    if let self = self {}
    43
    DONE
    

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44. ίʔυΛɺಡΈॻ͖͠΍͍͢ߏจ໦ʹ͢Δ
    ಡΈॻ͖͠΍͍͢ߏจ໦Λɺίʔυʹ͢Δ
    
    
    4XJGUͷίʔυ
    4XJGUͷίʔυ
    ಡΈॻ͖͠΍͍͢ߏจ໦
    ಡΈॻ͖͠΍͍͢ߏจ໦
    DONE
    44
    DONE
    

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45. 4XJGU4ZOUBYΛ࢖͏ͱɺ

    4XJGUͷߏจ໦ͷݕࠪ΍

    मਖ਼ͨ͠ίʔυΛੜ੒Ͱ͖ͨʂ
    ·ͱΊ
    45
    

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