Process Sample Code

1-Voices.swift

import Foundation

let process = Process()
process.launchPath = "/usr/bin/say"
process.arguments = ["-v", "?"]
let outPipe = Pipe()
process.standardOutput = outPipe
process.terminationHandler = { process in
  let outData = outPipe.fileHandleForReading.readDataToEndOfFile()
  let output = String(data: outData, encoding: .utf8) ?? ""

  print(output)
  let voices = parseVoices(output)
  print(voices)
}
try? process.run()
process.waitUntilExit()

2-Voices-Extension.swift

import Foundation

extension Process {
  @discardableResult
  static func launch(
    path: String,
    arguments: [String] = [],
    terminationHandler: @escaping (Int, Data, Data) -> Void
  ) throws -> Process {
    let process = Process()
    let outPipe = Pipe()
    let errorPipe = Pipe()
    process.standardOutput = outPipe
    process.standardError = errorPipe
    process.arguments = arguments
    process.launchPath = path
    process.terminationHandler = { process in
      let outData = outPipe.fileHandleForReading.readDataToEndOfFile()
      let errorData = errorPipe.fileHandleForReading.readDataToEndOfFile()
      let exitCode = Int(process.terminationStatus)
      terminationHandler(exitCode, outData, errorData)
    }
    try process.run()
    return process
  }
}

let process = try? Process.launch(
  path: "/usr/bin/say", 
  arguments: ["-v", "?"]
) { exitCode, outData, errData in
  let output = String(data: outData, encoding: .utf8) ?? ""
  print(output)
}
process?.waitUntilExit()

3-Voices-async-await.swift

import Foundation

extension Process {
  @discardableResult
  static func launch(
    path: String,
    arguments: [String] = [],
    terminationHandler: @escaping (Int, Data, Data) -> Void
  ) throws -> Process {
    let process = Process()
    let outPipe = Pipe()
    let errorPipe = Pipe()
    process.standardOutput = outPipe
    process.standardError = errorPipe
    process.arguments = arguments
    process.launchPath = path
    process.terminationHandler = { process in
      let outData = outPipe.fileHandleForReading.readDataToEndOfFile()
      let errorData = errorPipe.fileHandleForReading.readDataToEndOfFile()
      let exitCode = Int(process.terminationStatus)
      terminationHandler(exitCode, outData, errorData)
    }
    try process.run()
    return process
  }
  
  static func launch(
    path: String,
    arguments: [String] = []
  ) async throws -> (exitCode: Int, standardOutput: Data, standardError: Data) {
    try await withCheckedThrowingContinuation { continuation in
      do {
        try launch(path: path, arguments: arguments) { exitCode, outData, errData in
          continuation.resume(returning: (exitCode, outData, errData))
        }
      } catch let error {
        continuation.resume(throwing: error)
      }
    }
  }
}

guard let (exitCode, outData, errData) = try? await Process.launch(
    path: "/usr/bin/say",
    arguments: ["-v", "?"]
) else { exit(0) }

let output = String(data: outData, encoding: .utf8) ?? ""
print(output)

4-Voices-Parsing.swift

func parseVoices(_ output: String) -> [String] {
  output
    .components(separatedBy: "\n")
    .map {
      $0
        .components(separatedBy: "#")
        .first?
        .trimmingCharacters(in: .whitespaces)
        .components(separatedBy: CharacterSet.whitespaces)
        .dropLast()
        .filter { !$0.isEmpty }
        .joined(separator: " ")
      ?? ""
    }
    .filter { !$0.isEmpty }
}