Swift macrosの入門ハードルは意外と低いかも

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1. Swift macrosೖ໳ͷϋʔυϧ͸ҙ֎ͱ௿͍͔΋ 0
2. ࣗݾ঺հ ࠤ౻ଡҰ/ͯ͌ʔ ͓࢓ࣄɿiOSΤϯδχΞ 1
3. Swift macrosͱ͸ʁ ίϯύΠϧ࣌ʹίʔυΛࣗಈੜ੒͢Δػೳ ܁Γฦ͠ॻ͔ΕΔఆܕίʔυΛ࡟ݮ SwiftSyntaxͷߏจղੳɾੜ੒ͷػೳΛ࢖ͬͯಈ͍͍ͯΔ 2
4. Swift macrosͱ͸ʁ 2
5. Swift macrosͱ͸ʁ 2
6. Swift macrosͱ͸ʁ expansionϝιουͰɺSwiftSyntaxʹΑͬͯղੳ͞ΕͨߏจΛ࢖ͬͯίʔυΛੜ੒ ͠·͢ɻ 2
7. Swift macrosɺ೉ͦ͠͏ ೖ໳͢ΔͷʹSwiftSyntaxͷ஌͕ࣝඞཁͦ͏ 3
8. Swift macrosɺ೉ͦ͠͏ SwiftSyntax͕Θ͔Βͳ͍ɺɺ SwiftSyntaxා͍ɺɺ SwiftSyntaxͬͯͳʹɺɺ 3
9. Swift macrosɺ೉ͦ͠͏ ೖ໳͢ΔͷʹSwiftSyntaxͷ஌ࣝ͸ͦΜͳʹඞཁͳ ͔ͬͨʂ 3
10. ϚΫϩ࡞੒ͷجຊεςοϓ Swift macros͸ೖྗ஋ͱग़ྗ஋͕͋Δͱ͍͏఺Ͱ͸ؔ਺ͱࣅͨΑ͏ͳ΋ͷͰ͢ɻ ͳͷͰɺ࣮૷ͷεςοϓ΋ؔ਺ͱಉ͡Α͏ʹߟ͑Δ͜ͱ͕Ͱ͖·͢ɻ 4
11. ϚΫϩ࡞੒ͷجຊεςοϓ ೖྗ஋ΛܾΊΔ @modelConvert(SampleModel.self) struct SampleData { let id: String let text: String } 4
12. ϚΫϩ࡞੒ͷجຊεςοϓ ग़ྗ஋ΛܾΊΔ extension SampleData: ModelConvertible { typealias ModelType = SampleModel init(_ model: SampleModel) throws { id = model.id text = model.text } func toModel() throws -> SampleModel { return .init(id: id, text: text) } } 4
13. ϚΫϩ࡞੒ͷجຊεςοϓ ೖྗ஋ΛSwiftSyntaxͰղੳ͢Δ public static func expansion( of node: AttributeSyntax, attachedTo declaration: some DeclGroupSyntax, providingExtensionsOf type: some TypeSyntaxProtocol, conformingTo protocols: [TypeSyntax], in context: some MacroExpansionContext ) throws -> [ExtensionDeclSyntax] { ... } 4
14. ϚΫϩ࡞੒ͷجຊεςοϓ ग़ྗ஋ΛSwiftSyntaxͰੜ੒͢Δ ExtensionDeclSyntax(...) 4
15. "ߏจ໦ͷน"Λ৐Γӽ͑Δ SwiftSyntaxͰ͸ίʔυ͸ߏจ໦ͱͯ͠ද͞Ε͍ͯ·͢ɻ ߏจ໦ʹ͸SwiftSyntax⁶Swiftίʔυͷ૬ޓม׵Λॿ͚ΔͨΊͷඇৗʹ༗༻ͳ৘ใ͕٧ ·͍ͬͯ·͢ɻ ߏจ໦ΛݟΔϙΠϯτΛ཈͑Ε͹ɺϚΫϩ࣮૷ͷϋʔυϧ͕άοͱԼ͕Γ·͢ɻ 5
16. ߏจ໦͔Β೚ҙͷ৘ใΛऔಘ͢Δ ߏจ໦ͱSyntaxͷΦϒδΣΫτͷϓϩύςΟ͕ಉ͡Ͱ͋Δ͜ͱ͕Θ͔Ε͹ɺղੳ͸؆ ୯Ͱ͢ɻ AttributeSyntax ᵓᴷatSign: atSign ᵓᴷattributeName: IdentifierTypeSyntax │ ‹ᴷname: identifier("ModelConvert") ᵓᴷleftParen: leftParen ᵓᴷarguments: LabeledExprListSyntax │ ‹ᴷ<0>: LabeledExprSyntax │ ‹ᴷexpression: MemberAccessExprSyntax │ ᵓᴷbase: DeclReferenceExprSyntax │ │ ‹ᴷbaseName: identifier("SampleModel") │ ᵓᴷperiod: period │ ‹ᴷdeclName: DeclReferenceExprSyntax │ ‹ᴷbaseName: keyword(SwiftSyntax.Keyword.self) ‹ᴷrightParen: rightParen @modelConvert(SampleModel.self) 6
17. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
18. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
19. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
20. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
21. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
22. "baseName"ͷऔಘྫ AttributeSyntax ᵓᴷ... ‹ᴷarguments: LabeledExprListSyntax ‹ᴷ<0>: LabeledExprSyntax ‹ᴷexpression: MemberAccessExprSyntax ᵓᴷbase: DeclReferenceExprSyntax │ ‹ᴷbaseName: identifier("SampleModel") ᵓᴷperiod: period ‹ᴷdeclName: DeclReferenceExprSyntax… node.arguments!.cast(LabeledExprListSyntax.self).first! .expression.as(MemberAccessExprSyntax.self)? .base?.as(DeclReferenceExprSyntax.self)? .baseName 6
23. lldbίϚϯυͰߏจ໦Λදࣔ 6
24. ίʔυ͔ΒSyntaxͷΦϒδΣΫτ΁ม׵͢Δ ग़ྗ͍ͨ͠ίʔυͷߏจ໦ͷ಺༰͕Θ͔Ε͹ɺߏจ໦ʹهࡌ͞Ε͍ͯΔSyntaxͷܕͷΠχ γϟϥΠβͰࣗવͱSyntaxͷΦϒδΣΫτ΁ม׵Ͱ͖·͢ɻ SyntaxͷܕͷΠχγϟϥΠβͷύϥϝʔλ໊͸ɺߏจ໦ͷࢬͷཁૉ໊͕Ұக͍ͯ͠Δ͜ͱ ͕ɺ͜ͷํ๏Λ༰қʹ͍ͯ͠ΔϙΠϯτɻ 7
25. ExtensionDeclSyntaxͷੜ੒ྫ ߏจ໦ ExtensionDeclSyntax ᵓᴷattributes: AttributeListSyntax ᵓᴷmodifiers: DeclModifierListSyntax ᵓᴷextensionKeyword: keyword(SwiftSyntax.Keyword.extension) ᵓᴷextendedType: IdentifierTypeSyntax │ ‹ᴷname: identifier("SampleData") ᵓᴷinheritanceClause: InheritanceClauseSyntax │ ᵓᴷcolon: colon │ ‹ᴷinheritedTypes: InheritedTypeListSyntax │ ‹ᴷ<0>: InheritedTypeSyntax │ ‹ᴷtype: IdentifierTypeSyntax │ ‹ᴷname: identifier("ModelConvertible") ‹ᴷmemberBlock: MemberBlockSyntax ᵓᴷleftBrace: leftBrace ᵓᴷ... ... ߏจ໦ʹରԠ͢ΔΠχγϟϥΠβ ExtensionDeclSyntax( extensionKeyword: T##TokenSyntax, extendedType: T##TypeSyntaxProtocol, inheritanceClause: T##InheritanceClauseSyntax? memberBlock: T##MemberBlockSyntax ) 7
26. ExtensionDeclSyntaxͷੜ੒ྫ ߏจ໦ ExtensionDeclSyntax ᵓᴷattributes: AttributeListSyntax ᵓᴷmodifiers: DeclModifierListSyntax ᵓᴷextensionKeyword: keyword(SwiftSyntax.Keyword.extension) ᵓᴷextendedType: IdentifierTypeSyntax │ ‹ᴷname: identifier("SampleData") ᵓᴷinheritanceClause: InheritanceClauseSyntax │ ᵓᴷcolon: colon │ ‹ᴷinheritedTypes: InheritedTypeListSyntax │ ‹ᴷ<0>: InheritedTypeSyntax │ ‹ᴷtype: IdentifierTypeSyntax │ ‹ᴷname: identifier("ModelConvertible") ‹ᴷmemberBlock: MemberBlockSyntax ᵓᴷleftBrace: leftBrace ᵓᴷ... ... ߏจ໦ʹରԠ͢ΔΠχγϟϥΠβ ExtensionDeclSyntax( extensionKeyword: T##TokenSyntax, extendedType: T##TypeSyntaxProtocol, inheritanceClause: T##InheritanceClauseSyntax? memberBlock: T##MemberBlockSyntax ) 7
27. ExtensionDeclSyntaxͷੜ੒ྫ ߏจ໦ ExtensionDeclSyntax ᵓᴷattributes: AttributeListSyntax ᵓᴷmodifiers: DeclModifierListSyntax ᵓᴷextensionKeyword: keyword(SwiftSyntax.Keyword.extension) ᵓᴷextendedType: IdentifierTypeSyntax │ ‹ᴷname: identifier("SampleData") ᵓᴷinheritanceClause: InheritanceClauseSyntax │ ᵓᴷcolon: colon │ ‹ᴷinheritedTypes: InheritedTypeListSyntax │ ‹ᴷ<0>: InheritedTypeSyntax │ ‹ᴷtype: IdentifierTypeSyntax │ ‹ᴷname: identifier("ModelConvertible") ‹ᴷmemberBlock: MemberBlockSyntax ᵓᴷleftBrace: leftBrace ᵓᴷ... ... ߏจ໦ʹରԠ͢ΔΠχγϟϥΠβ ExtensionDeclSyntax( extensionKeyword: T##TokenSyntax, extendedType: T##TypeSyntaxProtocol, inheritanceClause: T##InheritanceClauseSyntax?, memberBlock: T##MemberBlockSyntax ) 7
28. ExtensionDeclSyntaxͷੜ੒ྫ ߏจ໦ ExtensionDeclSyntax ᵓᴷattributes: AttributeListSyntax ᵓᴷmodifiers: DeclModifierListSyntax ᵓᴷextensionKeyword: keyword(SwiftSyntax.Keyword.extension) ᵓᴷextendedType: IdentifierTypeSyntax │ ‹ᴷname: identifier("SampleData") ᵓᴷinheritanceClause: InheritanceClauseSyntax │ ᵓᴷcolon: colon │ ‹ᴷinheritedTypes: InheritedTypeListSyntax │ ‹ᴷ<0>: InheritedTypeSyntax │ ‹ᴷtype: IdentifierTypeSyntax │ ‹ᴷname: identifier("ModelConvertible") ‹ᴷmemberBlock: MemberBlockSyntax ᵓᴷleftBrace: leftBrace ᵓᴷ... ... ߏจ໦ʹରԠ͢ΔΠχγϟϥΠβ ExtensionDeclSyntax( extensionKeyword: T##TokenSyntax, extendedType: T##TypeSyntaxProtocol, inheritanceClause: T##InheritanceClauseSyntax?, memberBlock: T##MemberBlockSyntax ) 7
29. SwiftParserΛ࢖͑͹ίʔυ͔Βߏจ໦ΛऔಘͰ͖·͢ɻ var parser = Parser(""" extension SampleData: ModelConvertible { typealias ModelType = SampleModel init(_ model: SampleModel) throws { id = model.id text = model.text } func toModel() throws -> SampleModel { return .init(id: id, text: text) } } """) let block = CodeBlockSyntax.parse(from: &parser) 7
31. ஫ҙ఺ ೖ໳ϋʔυϧΛԼ͛Δ͜ͱΛॏ఺ʹஔ͍͓ͯΓɺSwift macrosͷϕετϓϥΫςΟεͳ ࣮૷ํ๏ͱ͸ݶΓ·ͤΜɻ public struct StringifyMacro: ExpressionMacro { public static func expansion( of node: some FreestandingMacroExpansionSyntax, in context: some MacroExpansionContext ) -> ExprSyntax { ... return "(\(argument), \(literal: argument.description))" } } 8
32. ·ͱΊ ߏจ໦ʹ͸ίʔυͱSwiftSyntaxͷ૬ޓม׵͢ΔͨΊͷ৘ใ͕٧·͍ͬͯΔ ߏจ໦ͷ৘ใΛ׆༻͢Ε͹ɺSwift macrosͷϋʔυϧΛେ͖͘Լ͛ΒΕΔ . ͋͞ɺօ͞Μ΋ϚΫϩΛ࡞ͬͯΈ·͠ΐ͏ʂ 9