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Merge pull request swiftlang#139 from akkyie/swift-syntax-builder
Initial implementation of declarative and type-safe wrapper
2 parents 89ce45a + 3dc22c9 commit 7fd8a8b

14 files changed

+715
-1
lines changed

‎Package.swift

+5-1
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@@ -8,6 +8,8 @@ let package = Package(
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.target(name: "_CSwiftSyntax"),
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.target(name: "SwiftSyntax", dependencies: ["_CSwiftSyntax"]),
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.testTarget(name: "SwiftSyntaxTest", dependencies: ["SwiftSyntax"], exclude: ["Inputs"]),
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.target(name: "SwiftSyntaxBuilder", dependencies: ["SwiftSyntax"]),
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.testTarget(name: "SwiftSyntaxBuilderTest", dependencies: ["SwiftSyntaxBuilder"]),
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.target(name: "lit-test-helper", dependencies: ["SwiftSyntax"])
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]
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)
@@ -20,6 +22,8 @@ import Darwin.C
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if getenv("SWIFT_SYNTAX_BUILD_SCRIPT") == nil {
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package.products.append(.library(name: "SwiftSyntax", targets: ["SwiftSyntax"]))
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package.products.append(.library(name: "SwiftSyntaxBuilder", targets: ["SwiftSyntaxBuilder"]))
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} else {
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package.products.append(.library(name: "SwiftSyntax", type: .dynamic, targets: ["SwiftSyntax"]))
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}
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package.products.append(.library(name: "SwiftSyntaxBuilder", type: .dynamic, targets: ["SwiftSyntaxBuilder"]))
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}

‎Sources/SwiftSyntaxBuilder/DeclBuildables.swift

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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftSyntax
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// MARK: - Protocols
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public protocol DeclListBuildable: SyntaxListBuildable {
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func buildDeclList(format: Format, leadingTrivia: Trivia) -> [DeclSyntax]
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}
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public protocol DeclBuildable: SyntaxBuildable, DeclListBuildable {
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func buildDecl(format: Format, leadingTrivia: Trivia) -> DeclSyntax
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}
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extension DeclBuildable {
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public func buildSyntax(format: Format, leadingTrivia: Trivia) -> Syntax {
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buildDecl(format: format, leadingTrivia: leadingTrivia)
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}
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public func buildDeclList(format: Format, leadingTrivia: Trivia) -> [DeclSyntax] {
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[buildDecl(format: format, leadingTrivia: leadingTrivia)]
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}
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}
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// MARK: - Function Builder
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@_functionBuilder
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public struct DeclListBuilder {
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public static func buildBlock(_ builders: DeclListBuildable...) -> DeclListBuildable {
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DeclList(builders: builders)
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}
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}
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// MARK: - List
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public struct DeclList: DeclListBuildable {
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let builders: [DeclListBuildable]
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public func buildDeclList(format: Format, leadingTrivia: Trivia) -> [DeclSyntax] {
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builders.flatMap { $0.buildDeclList(format: format, leadingTrivia: leadingTrivia) }
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}
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public func buildSyntaxList(format: Format, leadingTrivia: Trivia) -> [Syntax] {
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buildDeclList(format: format, leadingTrivia: leadingTrivia)
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}
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}
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extension DeclList {
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public static let empty: DeclList = DeclList(builders: [])
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}
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// MARK: - Buildables
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// MARK: Import
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public struct Import: DeclBuildable {
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let moduleName: String
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public init(_ moduleName: String) {
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self.moduleName = moduleName
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}
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public func buildDecl(format: Format, leadingTrivia: Trivia) -> DeclSyntax {
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let importToken = Tokens.import.withLeadingTrivia(leadingTrivia)
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let moduleNameToken = SyntaxFactory.makeIdentifier(moduleName)
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return ImportDeclSyntax {
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$0.useImportTok(importToken)
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$0.addPathComponent(AccessPathComponentSyntax {
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$0.useName(moduleNameToken)
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})
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}
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}
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}
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// MARK: Variables
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public protocol VariableMutability {
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static var token: TokenSyntax { get }
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}
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public enum VariableLetMutability: VariableMutability {
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public static let token = Tokens.let
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}
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public enum VariableVarMutability: VariableMutability {
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public static let token = Tokens.var
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}
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public typealias Let = Variable<VariableLetMutability>
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public typealias Var = Variable<VariableVarMutability>
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public struct Variable<Mutability: VariableMutability>: DeclBuildable {
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let name: String
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let type: String
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let initializer: ExprBuildable?
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public init(_ name: String, of type: String, value: ExprBuildable? = nil) {
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self.name = name
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self.type = type
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self.initializer = value
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}
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public func buildDecl(format: Format, leadingTrivia: Trivia) -> DeclSyntax {
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let mutabilityKeyword = Mutability.token.withLeadingTrivia(leadingTrivia)
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let nameIdentifier = SyntaxFactory.makeIdentifier(name)
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let namePattern = SyntaxFactory.makeIdentifierPattern(identifier: nameIdentifier)
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let typeIdentifier = SyntaxFactory.makeTypeIdentifier(type)
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let typeAnnotation = SyntaxFactory.makeTypeAnnotation(
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colon: Tokens.colon,
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type: typeIdentifier
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)
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let initClause = initializer.flatMap { builder -> InitializerClauseSyntax in
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let expr = builder.buildExpr(format: format, leadingTrivia: .zero)
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return SyntaxFactory.makeInitializerClause(equal: Tokens.equal, value: expr)
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}
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return VariableDeclSyntax {
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$0.useLetOrVarKeyword(mutabilityKeyword)
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$0.addBinding(PatternBindingSyntax {
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$0.usePattern(namePattern)
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$0.useTypeAnnotation(typeAnnotation)
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if let initClause = initClause {
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$0.useInitializer(initClause)
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}
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})
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}
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}
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}
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// MARK: Struct
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public struct Struct: DeclBuildable {
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let name: String
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let memberList: DeclListBuildable
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public init(
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_ name: String,
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@DeclListBuilder buildMemberList: () -> DeclListBuildable = { DeclList.empty }
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) {
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self.name = name
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self.memberList = buildMemberList()
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}
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public func buildDecl(format: Format, leadingTrivia: Trivia) -> DeclSyntax {
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let structKeyword = Tokens.struct.withLeadingTrivia(leadingTrivia)
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let declList = memberList.buildDeclList(
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format: format._indented(),
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leadingTrivia: .zero
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)
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return StructDeclSyntax {
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$0.useStructKeyword(structKeyword)
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$0.useIdentifier(SyntaxFactory.makeIdentifier(name))
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$0.useMembers(MemberDeclBlockSyntax {
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$0.useLeftBrace(Tokens.leftBrace.withLeadingTrivia(.spaces(1)))
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$0.useRightBrace(Tokens.rightBrace.withLeadingTrivia(.newlines(1) + format._makeIndent()))
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let format = format._indented()
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for decl in declList {
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let member = SyntaxFactory
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.makeMemberDeclListItem(decl: decl, semicolon: nil)
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.withLeadingTrivia(.newlines(1) + format._makeIndent())
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$0.addMember(member)
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}
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})
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}
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}
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}

‎Sources/SwiftSyntaxBuilder/ExprBuildables.swift

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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftSyntax
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// MARK: - Protocols
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public protocol ExprListBuildable: SyntaxListBuildable {
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func buildExprList(format: Format, leadingTrivia: Trivia) -> [ExprSyntax]
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}
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public protocol ExprBuildable: SyntaxBuildable, ExprListBuildable {
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func buildExpr(format: Format, leadingTrivia: Trivia) -> ExprSyntax
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}
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extension ExprBuildable {
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public func buildSyntax(format: Format, leadingTrivia: Trivia) -> Syntax {
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buildExpr(format: format, leadingTrivia: leadingTrivia)
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}
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public func buildExprList(format: Format, leadingTrivia: Trivia) -> [ExprSyntax] {
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[buildExpr(format: format, leadingTrivia: leadingTrivia)]
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}
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}
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// MARK: - Buildables
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// MARK: Integer Literal
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public struct IntegerLiteral: ExprBuildable {
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let value: Int
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public init(_ value: Int) {
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self.value = value
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}
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public func buildExpr(format: Format, leadingTrivia: Trivia) -> ExprSyntax {
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SyntaxFactory.makeIntegerLiteralExpr(
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digits: SyntaxFactory.makeIntegerLiteral(String(value))
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).withLeadingTrivia(leadingTrivia)
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}
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}
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extension IntegerLiteral: ExpressibleByIntegerLiteral {
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public init(integerLiteral value: Int) {
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self.init(value)
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}
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}
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// MARK: String Literal
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public struct StringLiteral: ExprBuildable {
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let value: String
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public init(_ value: String) {
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self.value = value
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}
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public func buildExpr(format: Format, leadingTrivia: Trivia) -> ExprSyntax {
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SyntaxFactory.makeStringLiteralExpr(value)
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.withLeadingTrivia(leadingTrivia)
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}
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}
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extension StringLiteral: ExpressibleByStringLiteral {
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public init(stringLiteral value: String) {
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self.init(value)
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}
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}

‎Sources/SwiftSyntaxBuilder/Format.swift

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//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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import SwiftSyntax
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public struct Format {
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public let indentWidth: Int
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private var indents: Int = 0
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public init(indentWidth: Int = 4) {
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self.indentWidth = indentWidth
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}
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}
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extension Format {
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public func _indented() -> Format {
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var copy = self
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copy.indents += 1
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return copy
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}
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public func _makeIndent() -> Trivia {
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return indents == 0 ? .zero : Trivia.spaces(indents * indentWidth)
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}
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}

‎Sources/SwiftSyntaxBuilder/README.md

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# SwiftSyntaxBuilder
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Declarative and type-safe wrapper around SwiftSyntax.
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## Example Usage
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```swift
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let sourceFile = SourceFile {
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Import("SwiftSyntax")
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Struct("ExampleStruct") {
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Let("syntax", of: "Syntax")
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}
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}
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let syntax = sourceFile.buildSyntax(format: format, leadingTrivia: .zero)
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var text = ""
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syntax.write(to: &text)
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print(text)
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```
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prints:
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```swift
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import SwiftSyntax
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struct ExampleStruct {
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let syntax: Syntax
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}
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```

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