$ TOOLCHAINS=swift swift run format-example Package.swift Compile Swift Module 'SwiftSyntax' (16 sources) Linking ./.build/x86_64-apple-macosx10.10/debug/format-example -- debug -- [0] process type: SourceFileSyntax [1] process type: SyntaxCollection<DeclSyntax> [2] process type: UnknownDeclSyntax [3] process type: TokenSyntax text: import leading: Trivia(pieces: [// swift-tools-version:4.0, ]) trailing: Trivia(pieces: [ ]) [3] process type: TokenSyntax text: PackageDescription leading: Trivia(pieces: []) trailing: Trivia(pieces: []) [2] process type: TopLevelCodeDeclSyntax [3] process type: CodeBlockSyntax [1] process type: TokenSyntax text: leading: Trivia(pieces: [ ]) trailing: Trivia(pieces: [])