Add support for async/await where available #326
Description
async/await is useful for writing clean and concise code for building small CLI tools, especially ones that interact with the network or the file system.
Since @main now supports an async variant, I was able to add such support to a prototype with the following code:
// entry.swift
@available(macOS 12.0, *)
protocol AsyncParsableCommand: ParsableCommand {
mutating func runAsync() async throws
}
extension ParsableCommand {
static func main(_ arguments: [String]? = nil) async {
do {
var command = try parseAsRoot(arguments)
if #available(macOS 12.0, *), var asyncCommand = command as? AsyncParsableCommand {
try await asyncCommand.runAsync()
} else {
try command.run()
}
} catch {
exit(withError: error)
}
}
}
struct MainCommand: AsyncParsableCommand {
@Option()
var name: String = "Anon"
func runAsync() async throws {
print("Hello, \(name)")
// await something...
}
}
@main
struct MainApp {
static func main() async {
await MainCommand.main()
}
}
Having this be officially supported by swift-argument-parser would be ideal.