The command sample might be helpful if you would like to offer a standard interface for various actions that can be executed later in time. Often it is an object that encapsulates all the data wanted to run the underlying motion correctly.
Instructions are sometimes used to deal with consumer interface actions, create undo managers, or handle transactions. Let’s have a look at a command sample implementation in Swift by making a command line argument handler with emojis. 💾
#!/usr/bin/env swift
import Basis
protocol Command {
func execute()
}
class HelpCommand: Command {
func execute() {
Assist().information()
}
}
class Assist {
func information() {
print("""
🤖 Commander 🤖
v1.0
Obtainable instructions:
👉 assist This command
👉 ls Listing paperwork
Bye! 👋
""")
}
}
class ListCommand: Command {
func execute() {
Listing().homeDirectoryContents()
}
}
class Listing {
func homeDirectoryContents() {
let fileManager = FileManager.default
guard let documentsURL = fileManager.urls(for: .documentDirectory, in: .userDomainMask).first else {
print("Couldn't open paperwork listing")
exit(-1)
}
do {
let fileURLs = strive fileManager.contentsOfDirectory(at: documentsURL, includingPropertiesForKeys: nil)
print("nt📁 Itemizing paperwork listing:n")
print(fileURLs.map { "tt💾 " + $0.lastPathComponent }.joined(separator: "nn") + "n" )
}
catch {
print(error.localizedDescription)
exit(-1)
}
}
}
class App {
var instructions: [String:Command] = [:]
init() {
self.instructions["help"] = HelpCommand()
self.instructions["ls"] = ListCommand()
}
func run() {
let arguments = CommandLine.arguments[1...]
guard let key = arguments.first, self.instructions[key] != nil else "))]")
exit(-1)
self.instructions[key]!.execute()
}
}
App().run()In the event you save this file, can run it by merely typing ./file-name.swift from a terminal window. The Swift compiler will handle the remainder. ⚒
