@main をつかった main.swift がない executable な Product が swift build できない気がするerror: executable product 'meowmeow' expects target 'meowmeow' to be executable; an executable target requires a 'main.swift' file@main な Struct があるから実行できるexecutableProductTargetNotExecutable かな。 /// Determine target type based on the sources. fileprivate func computeTargetType() -> Target.Kind { let isLibrary = !relativePaths.contains { path in let file = path.basename.lowercased() // Look for a main.xxx file avoiding cases like main.xxx.xxx return file.hasPrefix("main.") && String(file.filter({$0 == "."})).count == 1 } return isLibrary ? .library : .executable }