file.swift

import Darwin

func printFile(fileName: String) {
  var line: UnsafeMutablePointer<Int8> = nil
  var len = 0
  var read = 0
  let file = fopen(fileName, "r")
  guard file != nil else { return }
  func goto(label: String) {
    switch label {
    case "start":
      goto("cond")
    case "cond":
      read = getline(&line, &len, file)
      if read == -1 {
        goto("end")
      } else {
        goto("body")
      }
    case "body":
      print("Retrieved line of length \(read):")
      print(String.fromCString(line)!)
      goto("cond")
    case "end":
      if file != nil { fclose(file) }
    default: break
    }
  }
  goto("start")
}

if Process.arguments.count > 1 {
  printFile(Process.arguments[1])
}