src/Pure/System/options.scala

+/*  Title:      Pure/System/options.scala
+    Author:     Makarius
+
+Stand-alone options with external string representation.
+*/
+
+package isabelle
+
+
+import java.io.File
+
+
+object Options
+{
+  abstract class Type
+  {
+    def print: String = toString.toLowerCase
+    def init: String
+  }
+  case object Bool extends Type { def init = "false" }
+  case object Int extends Type { def init = "0" }
+  case object Real extends Type { def init = "0.0" }
+  case object String extends Type { def init = "" }
+
+  case class Opt(typ: Type, description: String, value: String)
+
+  val empty: Options = new Options()
+
+
+  /* parsing */
+
+  private object Parser extends Parse.Parser
+  {
+    val DECLARE = "declare"
+    val DEFINE = "define"
+
+    val syntax = Outer_Syntax.empty + ":" + "=" + DECLARE + DEFINE
+
+    val entry: Parser[Options => Options] =
+    {
+      val option_name = atom("option name", _.is_xname)
+      val option_type = atom("option type", _.is_ident)
+      val option_value = atom("option value", tok => tok.is_name || tok.is_float)
+
+      keyword(DECLARE) ~! (option_name ~ keyword(":") ~ option_type ~ opt(text)) ^^
+        { case _ ~ (x ~ _ ~ y ~ z) => (options: Options) =>
+            options.declare(x, y, z.getOrElse("")) } |
+      keyword(DEFINE) ~! (option_name ~ keyword("=") ~ option_value) ^^
+        { case _ ~ (x ~ _ ~ y) => (options: Options) =>
+            options.define(x, y) }
+    }
+
+    def parse_entries(file: File): List[Options => Options] =
+    {
+      val toks = syntax.scan(Standard_System.read_file(file))
+      parse_all(rep(entry), Token.reader(toks, file.toString)) match {
+        case Success(result, _) => result
+        case bad => error(bad.toString)
+      }
+    }
+  }
+
+  val OPTIONS = Path.explode("etc/options")
+
+  def init(): Options =
+  {
+    var options = empty
+    for {
+      dir <- Isabelle_System.components()
+      file = Isabelle_System.platform_file(dir + OPTIONS)
+      if file.isFile
+      entry <- Parser.parse_entries(file)
+    } {
+      try { options = entry(options) }
+      catch { case ERROR(msg) => error(msg + " (file " + quote(file.toString) + ")") }
+    }
+    options
+  }
+}
+
+
+final class Options private(options: Map[String, Options.Opt] = Map.empty)
+{
+  override def toString: String = options.iterator.mkString("Options (", ",", ")")
+
+
+  /* basic operations */
+
+  private def check_name(name: String): Options.Opt =
+    options.get(name) match {
+      case Some(opt) => opt
+      case None => error("Undeclared 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)
+  }
+
+  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))
+    }
+  }
+
+  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)))
+  }
+
+
+
+
+  /* external declare and define */
+
+  def declare(name: String, typ_name: 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("Malformed type for option " + quote(name) + " : " + quote(typ_name))
+          }
+        new Options(options + (name -> Options.Opt(typ, description, typ.init)))
+    }
+  }
+
+  def define(name: String, value: String): Options =
+  {
+    val opt = check_name(name)
+    val result = new Options(options + (name -> opt.copy(value = value)))
+    opt.typ match {
+      case Options.Bool => result.bool(name); ()
+      case Options.Int => result.int(name); ()
+      case Options.Real => result.real(name); ()
+      case Options.String => result.string(name); ()
+    }
+    result
+  }
+
+
+  /* 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)
+  }
+}