src/Pure/System/options.scala

some support for persistent user preferences;

/*  Title:      Pure/System/options.scala
    Author:     Makarius

Stand-alone options with external string representation.
*/

package isabelle


import java.util.Calendar


object Options
{
  type Spec = (String, Option[String])

  val empty: Options = new Options()


  /* representation */

  sealed abstract class Type
  {
    def print: String = toString.toLowerCase
  }
  private case object Bool extends Type
  private case object Int extends Type
  private case object Real extends Type
  private case object String extends Type

  case class Opt(typ: Type, value: String, description: String)


  /* parsing */

  private val OPTION = "option"
  private val OPTIONS = Path.explode("etc/options")
  private val PREFS = Path.explode("$ISABELLE_HOME_USER/etc/preferences")
  private val PREFS_BACKUP = Path.explode("$ISABELLE_HOME_USER/etc/preferences~")

  lazy val options_syntax = Outer_Syntax.init() + ":" + "=" + "--" + (OPTION, Keyword.THY_DECL)
  lazy val prefs_syntax = Outer_Syntax.init() + "="

  object Parser extends Parse.Parser
  {
    val option_name = atom("option name", _.is_xname)
    val option_type = atom("option type", _.is_ident)
    val option_value =
      opt(token("-", tok => tok.is_sym_ident && tok.content == "-")) ~ atom("nat", _.is_nat) ^^
        { case s ~ n => if (s.isDefined) "-" + n else n } |
      atom("option value", tok => tok.is_name || tok.is_float)

    val option_entry: Parser[Options => Options] =
    {
      command(OPTION) ~! (option_name ~ keyword(":") ~ option_type ~
      keyword("=") ~ option_value ~ (keyword("--") ~! text ^^ { case _ ~ x => x } | success(""))) ^^
        { case _ ~ (a ~ _ ~ b ~ _ ~ c ~ d) => (options: Options) => options.declare(a, b, c, d) }
    }

    val prefs_entry: Parser[Options => Options] =
    {
      option_name ~ (keyword("=") ~! option_value) ^^
      { case a ~ (_ ~ b) => (options: Options) => options + (a, b) }
    }

    def parse_file(syntax: Outer_Syntax, parser: Parser[Options => Options],
      options: Options, file: Path): Options =
    {
      val toks = syntax.scan(File.read(file))
      val ops =
        parse_all(rep(parser), Token.reader(toks, file.implode)) match {
          case Success(result, _) => result
          case bad => error(bad.toString)
        }
      try { (options /: ops) { case (opts, op) => op(opts) } }
      catch { case ERROR(msg) => error(msg + Position.str_of(file.position)) }
    }
  }

  def init_defaults(): Options =
  {
    var options = empty
    for {
      dir <- Isabelle_System.components()
      file = dir + OPTIONS if file.is_file
    } { options = Parser.parse_file(options_syntax, Parser.option_entry, options, file) }
    options
  }

  def init(): Options = init_defaults().load_prefs()


  /* encode */

  val encode: XML.Encode.T[Options] = (options => options.encode)


  /* command line entry point */

  def main(args: Array[String])
  {
    Command_Line.tool {
      args.toList match {
        case export_file :: more_options =>
          val options = (Options.init() /: more_options)(_ + _)

          if (export_file == "") java.lang.System.out.println(options.print)
          else File.write(Path.explode(export_file), YXML.string_of_body(options.encode))

          0
        case _ => error("Bad arguments:\n" + cat_lines(args))
      }
    }
  }
}


final class Options private(protected val options: Map[String, Options.Opt] = Map.empty)
{
  override def toString: String = options.iterator.mkString("Options (", ",", ")")

  def print: String =
    cat_lines(options.toList.sortBy(_._1).map({ case (name, opt) =>
      "option " + name + " : " + opt.typ.print + " = " +
        (if (opt.typ == Options.String) quote(opt.value) else opt.value) +
      "\n  -- " + quote(opt.description) }))


  /* check */

  private def check_name(name: String): Options.Opt =
    options.get(name) match {
      case Some(opt) => opt
      case None => error("Unknown option " + quote(name))
    }

  private def check_type(name: String, typ: Options.Type): Options.Opt =
  {
    val opt = check_name(name)
    if (opt.typ == typ) opt
    else error("Ill-typed option " + quote(name) + " : " + opt.typ.print + " vs. " + typ.print)
  }


  /* basic operations */

  private def put[A](name: String, typ: Options.Type, value: String): Options =
  {
    val opt = check_type(name, typ)
    new Options(options + (name -> opt.copy(value = value)))
  }

  private def get[A](name: String, typ: Options.Type, parse: String => Option[A]): A =
  {
    val opt = check_type(name, typ)
    parse(opt.value) match {
      case Some(x) => x
      case None =>
        error("Malformed value for option " + quote(name) +
          " : " + typ.print + " =\n" + quote(opt.value))
    }
  }


  /* internal lookup and update */

  val bool = new Object
  {
    def apply(name: String): Boolean = get(name, Options.Bool, Properties.Value.Boolean.unapply)
    def update(name: String, x: Boolean): Options =
      put(name, Options.Bool, Properties.Value.Boolean(x))
  }

  val int = new Object
  {
    def apply(name: String): Int = get(name, Options.Int, Properties.Value.Int.unapply)
    def update(name: String, x: Int): Options =
      put(name, Options.Int, Properties.Value.Int(x))
  }

  val real = new Object
  {
    def apply(name: String): Double = get(name, Options.Real, Properties.Value.Double.unapply)
    def update(name: String, x: Double): Options =
      put(name, Options.Real, Properties.Value.Double(x))
  }

  val string = new Object
  {
    def apply(name: String): String = get(name, Options.String, s => Some(s))
    def update(name: String, x: String): Options = put(name, Options.String, x)
  }


  /* external updates */

  private def check_value(name: String): Options =
  {
    val opt = check_name(name)
    opt.typ match {
      case Options.Bool => bool(name); this
      case Options.Int => int(name); this
      case Options.Real => real(name); this
      case Options.String => string(name); this
    }
  }

  def declare(name: String, typ_name: String, value: String, description: String = ""): Options =
  {
    options.get(name) match {
      case Some(_) => error("Duplicate declaration of option " + quote(name))
      case None =>
        val typ =
          typ_name match {
            case "bool" => Options.Bool
            case "int" => Options.Int
            case "real" => Options.Real
            case "string" => Options.String
            case _ => error("Unknown type for option " + quote(name) + " : " + quote(typ_name))
          }
        val opt = Options.Opt(typ, value, description)
        (new Options(options + (name -> opt))).check_value(name)
    }
  }

  def + (name: String, value: String): Options =
  {
    val opt = check_name(name)
    (new Options(options + (name -> opt.copy(value = value)))).check_value(name)
  }

  def + (name: String, opt_value: Option[String]): Options =
  {
    val opt = check_name(name)
    opt_value match {
      case Some(value) => this + (name, value)
      case None if opt.typ == Options.Bool => this + (name, "true")
      case None => error("Missing value for option " + quote(name) + " : " + opt.typ.print)
    }
  }

  def + (str: String): Options =
  {
    str.indexOf('=') match {
      case -1 => this + (str, None)
      case i => this + (str.substring(0, i), str.substring(i + 1))
    }
  }

  def ++ (specs: List[Options.Spec]): Options =
    (this /: specs)({ case (x, (y, z)) => x + (y, z) })


  /* encode */

  def encode: XML.Body =
  {
    import XML.Encode.{string => str, _}
    list(triple(str, str, str))(
      options.toList.map({ case (name, opt) => (name, opt.typ.print, opt.value) }))
  }


  /* user preferences */

  def load_prefs(): Options =
    if (Options.PREFS.is_file)
      Options.Parser.parse_file(
        Options.prefs_syntax, Options.Parser.prefs_entry, this, Options.PREFS)
    else this

  def save_prefs()
  {
    val current_defaults = Options.init_defaults()
    val changed =
      (for {
        (name, opt1) <- current_defaults.options.iterator
        opt2 <- options.get(name)
        if (opt1.value != opt2.value)
      } yield (name, opt2.value)).toList
    val prefs =
      changed.sortBy(_._1)
        .map({ case (x, y) => x + " = " + Outer_Syntax.quote_string(y) + "\n" }).mkString

    Options.PREFS.file renameTo Options.PREFS_BACKUP.file
    File.write(Options.PREFS,
      "(* generated by Isabelle " + Calendar.getInstance.getTime + " *)\n\n" + prefs)
  }
}