[NSBarcelona/AppTalks Manchester] - Delightful Swift CLI applications

Transcript

1. Delightful Swift CLI apps @polpielladev
2. Hi! I’m Pol Senior software engineer at the BBC
3. Tooling + Swift ❤ • Familiar language • Low memory footprint • Type safety • Mature ecosystem • Great open-source community • Build for multiple platforms
4. 🤩 The beauty of Swift https://github.com/icanzilb/timeui
5. Some great examples built with Swift of course! ❤ • Sourcery - https://github.com/krzysztofzablocki/Sourcery • SwiftLint - https://github.com/realm/SwiftLint • Tuist - https://github.com/tuist/tuist • SwiftGen - https://github.com/SwiftGen/SwiftGen • Publish CLI - https://github.com/JohnSundell/Publish • Vapor toolbox - https://github.com/vapor/toolbox
6. import ArgumentParser @main struct Repeat: AsyncParsableCommand { @Flag(help: "Include a counter with each repetition.") var includeCounter = false @Option(name: .shortAndLong, help: "The number of times to repeat 'phrase'.") var count: Int? = nil @Argument(help: "The phrase to repeat.") var phrase: String func run() async throws { let repeatCount = count ?? 2 for i in 1 ... repeatCount { if includeCounter { await someAsyncOperation() } else { print(phrase) } } } } https://github.com/apple/swift-argument-parser
7. import ArgumentParser @main struct Repeat: AsyncParsableCommand { @Flag(help: "Include a counter with each repetition.") var includeCounter = false @Option(name: .shortAndLong, help: "The number of times to repeat 'phrase'.") var count: Int? = nil @Argument(help: "The phrase to repeat.") var phrase: String func run() async throws { let repeatCount = count ?? 2 for i in 1 ... repeatCount { if includeCounter { await someAsyncOperation() } else { print(phrase) } } } } https://github.com/apple/swift-argument-parser
8. import ArgumentParser @main struct Repeat: AsyncParsableCommand { @Flag(help: "Include a counter with each repetition.") var includeCounter = false @Option(name: .shortAndLong, help: "The number of times to repeat 'phrase'.") var count: Int? = nil @Argument(help: "The phrase to repeat.") var phrase: String func run() async throws { let repeatCount = count ?? 2 for i in 1 ... repeatCount { if includeCounter { await someAsyncOperation() } else { print(phrase) } } } } https://github.com/apple/swift-argument-parser
10. ✨ Swift on Linux! https://github.com/keith/swiftpm-linux-cross
11. 🤩 Now easier? https://github.com/swift-server/swiftly
12. 🚀 Automating releases! https://www.polpiella.dev/automating-swift-package-releases-with-github-actions
13. What is missing though?
14. Making tooling that looks great is hard… • UX Developer experience is not great • Other languages and ecosystems are more advanced • Javascript is a great example! • We need to aim for delightful! ✨
17. The ecosystem allows for delightful • Ora - https://github.com/sindresorhus/ora • Chalk - https://github.com/chalk/chalk • Prompts - https://github.com/terkelg/prompts • Commander - https://github.com/tj/commander.js • Clack - https://github.com/natemoo-re/clack
18. Swift has some tools like that… • Chalk - https://github.com/mxcl/Chalk • Commander - https://github.com/kylef/Commander • TermKit - https://github.com/migueldeicaza/TermKit • ANSITerminal - https://github.com/pakLebah/ANSITerminal
19. But how do you do this?
20. ANSI escape sequences • String sequences • Perform operations in the terminal • Control the cursor’s position, change colour of text, etc. • Supported by Unix operating systems • Support from Windows 10
21. Modifying text print("Hello, world!") "Hello, world!" Output
22. Modifying text print("\u{1B}[31mHello, world!") "Hello, world!" Output Start Sequence Red colour
23. Modifying text print("\u{1B}[1;31mHello, world!") "Hello, world!" Output
24. Don’t give up just yet… https://github.com/pakLebah/ANSITerminal
25. Modifying text print("Hello, world!") "Hello, world!" Output
26. Modifying text import ANSITerminal print("Hello, world!") "Hello, world!" Output
27. Modifying text "Hello, world!" Output import ANSITerminal print("Hello, world!".red)
28. Modifying text "Hello, world!" Output import ANSITerminal print("Hello, world!".red.bold)
29. "Hello, world!" ▋ Output Moving the cursor print("Hello World!")
30. "Hello, world!"▋ Output Moving the cursor import ANSITerminal write("Hello World!")
31. "Hello, world!"▋ Output Moving the cursor import ANSITerminal let startPosition = readCursorPos() write("Hello World!")
32. ▋"Hello, world!" Output Moving the cursor import ANSITerminal let startPosition = readCursorPos() write("Hello World!")
33. ▋"Hello, world!" Output Moving the cursor import ANSITerminal let startPosition = readCursorPos() write("Hello World!") moveTo(startPosition.row, startPosition.col)
34. ▋"Hello, world!" Output Moving the cursor import ANSITerminal let startPosition = readCursorPos() write("Hello World!".foreColor(244)) moveTo(startPosition.row, startPosition.col)
35. "Hello▋ world!" Output Moving the cursor import ANSITerminal let startPosition = readCursorPos() write("Hello World!".foreColor(244)) moveTo(startPosition.row, startPosition.col) write("Hello")
36. ⚠ Something to consider
37. Someone, probably all the time! “It’s not you, it’s Xcode!”
38. 🤩 The terminal is your BFF
39. An interactive component
40. I’ve been porting Clack to Swift https://github.com/polpielladev/clack-swift
41. Let’s build a Text Input component • Custom text entry • Placeholder • Validation • Support for secure text entry • Headless + UI
42. Headless first
43. import Foundation import ANSITerminal func readTextInput( validate: (String) -> Bool = { _ in true }, validationFailed: () -> Void = {}, onNewCharacter: (Character) -> Void, onDelete: (Int, Int) -> Void, removePlaceholder: () -> Void, showPlaceholder: () -> Void ) - > String { }
44. import Foundation import ANSITerminal func readTextInput( validate: (String) -> Bool = { _ in true }, validationFailed: () -> Void = {}, onNewCharacter: (Character) -> Void, onDelete: (Int, Int) -> Void, removePlaceholder: () -> Void, showPlaceholder: () -> Void ) - > String { }
45. import Foundation import ANSITerminal func readTextInput( validate: (String) -> Bool = { _ in true }, validationFailed: () -> Void = {}, onNewCharacter: (Character) -> Void, onDelete: (Int, Int) -> Void, removePlaceholder: () -> Void, showPlaceholder: () -> Void ) - > String { }
46. import Foundation import ANSITerminal func readTextInput( validate: (String) -> Bool = { _ in true }, validationFailed: () -> Void = {}, onNewCharacter: (Character) -> Void, onDelete: (Int, Int) -> Void, removePlaceholder: () -> Void, showPlaceholder: () -> Void ) - > String { }
47. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
48. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
49. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
50. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
51. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
52. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
53. var output = "" while true { clearBuffer() if keyPressed() { let char = readChar() if char == NonPrintableChar.enter.char() { if validate(output) { break } else { validationFailed() } } else if char == NonPrintableChar.del.char() { let cursorPosition = readCursorPos() if output.count > 0 { onDelete(cursorPosition.row, cursorPosition.col - 1) _ = output.removeLast() } if output.count == 0 { showPlaceholder() } } if !isNonPrintable(char: char) { if output.isEmpty { removePlaceholder() } onNewCharacter(char) output.append(char) } } } return output
54. Adding the head!
55. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
56. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
57. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
58. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
59. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
60. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write(placeholder.foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
61. let textInput = readTextInput(validate: { !$0.isEmpty }, validationFailed: { validationFailed = true let currentPosition = readCursorPos() writeAt(promptStartLine, 0, ANSIChar.warn) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 11) writeAt(bottomPos.row, bottomPos.col + 1, validator ?. failureString ?? "") moveTo(currentPosition.row, currentPosition.col) }, onNewCharacter: { char in if validationFailed { let currentPosition = readCursorPos() writeAt(promptStartLine, 0, "◆".foreColor(81).bold) updateBracketColor(fromLine: promptStartLine, toLine: bottomPos.row, withColor: 81) moveTo(bottomPos.row, bottomPos.col + 1) clearToEndOfLine() moveTo(currentPosition.row, currentPosition.col) validationFailed = false } write("\(isSecureEntry ? "▪" : char)") }, onDelete: { row, col in moveTo(row, col); deleteChar() }, removePlaceholder: { moveTo(initialCursorPosition.row, initialCursorPosition.col) clearToEndOfLine() }, showPlaceholder: { write("sk- ... ".foreColor(244)) moveTo(initialCursorPosition.row, initialCursorPosition.col) })
62. 🤯 That’s literally it!
63. 💪 Leverage the power of Unicode!
64. Ora’s spinners are made of braille pattern characters
65. clack-swift is open source! https://github.com/polpielladev/clack-swift
66. An example
68. struct Auth: AsyncParsableCommand { func run() async throws { intro(title: "Hi! Set your token to use Chatty!") let validator = Validator( validate: { !$0.isEmpty }, failureString: "The OpenAI API token can not be empty ... " ) let token = text( question: "Enter your OpenAPI token", placeholder: "sk- ... ", validator: validator, isSecureEntry: true ) let keychain = Keychain(service: "dev.polpiella.chatty") keychain["openaitoken"] = token outro( text: "You're all set! You can now run " + "`chatty`".magenta.onWhite + " to converse ... " ) } }
69. struct Auth: AsyncParsableCommand { func run() async throws { intro(title: "Hi! 👋 Set your token to use Chatty!") let validator = Validator( validate: { !$0.isEmpty }, failureString: "The OpenAI API token can not be empty ... " ) let token = text( question: "Enter your OpenAPI token", placeholder: "sk- ... ", validator: validator, isSecureEntry: true ) let keychain = Keychain(service: "dev.polpiella.chatty") keychain["openaitoken"] = token outro( text: "You're all set! You can now run " + "`chatty`".magenta.onWhite + " to converse ... " ) } }
70. struct Auth: AsyncParsableCommand { func run() async throws { intro(title: "Hi! 👋 Set your token to use Chatty!") let validator = Validator( validate: { !$0.isEmpty }, failureString: "The OpenAI API token can not be empty ... " ) let token = text( question: "Enter your OpenAPI token", placeholder: "sk- ... ", validator: validator, isSecureEntry: true ) let keychain = Keychain(service: "dev.polpiella.chatty") keychain["openaitoken"] = token outro( text: "You're all set! You can now run " + "`chatty`".magenta.onWhite + " to converse ... " ) } }
71. struct Auth: AsyncParsableCommand { func run() async throws { intro(title: "Hi! 👋 Set your token to use Chatty!") let validator = Validator( validate: { !$0.isEmpty }, failureString: "The OpenAI API token can not be empty ... " ) let token = text( question: "Enter your OpenAPI token", placeholder: "sk- ... ", validator: validator, isSecureEntry: true ) let keychain = Keychain(service: "dev.polpiella.chatty") keychain["openaitoken"] = token outro( text: "You're all set! You can now run " + "`chatty`".magenta.onWhite + " to converse ... " ) } }
72. struct Auth: AsyncParsableCommand { func run() async throws { intro(title: "Hi! 👋 Set your token to use Chatty!") let validator = Validator( validate: { !$0.isEmpty }, failureString: "The OpenAI API token can not be empty ... " ) let token = text( question: "Enter your OpenAPI token", placeholder: "sk- ... ", validator: validator, isSecureEntry: true ) let keychain = Keychain(service: "dev.polpiella.chatty") keychain["openaitoken"] = token outro( text: "✅ You're all set! You can now run " + "`chatty`".magenta.onWhite + " to converse ... " ) } }
73. intro() text() outro()
74. 🤩 Chatty-cli is open source! https://github.com/polpielladev/chatty-cli
75. Say hi! https://pol.link