src/Pure/Isar/outer_syntax.scala

don't be so aggresive for a public test function and raise only BAD_THM instead of ERROR

/*  Title:      Pure/Isar/outer_syntax.scala
    Author:     Makarius

Isabelle/Isar outer syntax.
*/

package isabelle


import scala.util.parsing.input.{Reader, CharSequenceReader}
import scala.collection.mutable


object Outer_Syntax
{
  def quote_string(str: String): String =
  {
    val result = new StringBuilder(str.length + 10)
    result += '"'
    for (s <- Symbol.iterator(str)) {
      if (s.length == 1) {
        val c = s(0)
        if (c < 32 && c != YXML.X && c != YXML.Y || c == '\\' || c == '"') {
          result += '\\'
          if (c < 10) result += '0'
          if (c < 100) result += '0'
          result ++= (c.asInstanceOf[Int].toString)
        }
        else result += c
      }
      else result ++= s
    }
    result += '"'
    result.toString
  }

  val empty: Outer_Syntax = new Outer_Syntax()

  def init(): Outer_Syntax = new Outer_Syntax(completion = Completion.init())
}

final class Outer_Syntax private(
  keywords: Map[String, (String, List[String])] = Map.empty,
  lexicon: Scan.Lexicon = Scan.Lexicon.empty,
  val completion: Completion = Completion.empty,
  val completion_context: Completion.Context = Completion.Context.outer,
  val has_tokens: Boolean = true)
{
  override def toString: String =
    (for ((name, (kind, files)) <- keywords) yield {
      if (kind == Keyword.MINOR) quote(name)
      else
        quote(name) + " :: " + quote(kind) +
        (if (files.isEmpty) "" else " (" + commas_quote(files) + ")")
    }).toList.sorted.mkString("keywords\n  ", " and\n  ", "")

  def keyword_kind_files(name: String): Option[(String, List[String])] = keywords.get(name)
  def keyword_kind(name: String): Option[String] = keyword_kind_files(name).map(_._1)

  def thy_load(span: List[Token]): Option[List[String]] =
    keywords.get(Command.name(span)) match {
      case Some((Keyword.THY_LOAD, exts)) => Some(exts)
      case _ => None
    }

  val thy_load_commands: List[(String, List[String])] =
    (for ((name, (Keyword.THY_LOAD, files)) <- keywords.iterator) yield (name, files)).toList

  def + (name: String, kind: (String, List[String]), replace: Option[String]): Outer_Syntax =
  {
    val keywords1 = keywords + (name -> kind)
    val lexicon1 = lexicon + name
    val completion1 =
      if (Keyword.control(kind._1) || replace == Some("")) completion
      else completion + (name, replace getOrElse name)
    new Outer_Syntax(keywords1, lexicon1, completion1, completion_context, true)
  }

  def + (name: String, kind: (String, List[String])): Outer_Syntax =
    this + (name, kind, Some(name))
  def + (name: String, kind: String): Outer_Syntax =
    this + (name, (kind, Nil), Some(name))
  def + (name: String, replace: Option[String]): Outer_Syntax =
    this + (name, (Keyword.MINOR, Nil), replace)
  def + (name: String): Outer_Syntax = this + (name, None)

  def add_keywords(keywords: Thy_Header.Keywords): Outer_Syntax =
    (this /: keywords) {
      case (syntax, (name, Some((kind, _)), replace)) =>
        syntax +
          (Symbol.decode(name), kind, replace) +
          (Symbol.encode(name), kind, replace)
      case (syntax, (name, None, replace)) =>
        syntax +
          (Symbol.decode(name), replace) +
          (Symbol.encode(name), replace)
    }

  def is_command(name: String): Boolean =
    keyword_kind(name) match {
      case Some(kind) => kind != Keyword.MINOR
      case None => false
    }

  def heading_level(name: String): Option[Int] =
  {
    keyword_kind(name) match {
      case _ if name == "header" => Some(0)
      case Some(Keyword.THY_HEADING1) => Some(1)
      case Some(Keyword.THY_HEADING2) | Some(Keyword.PRF_HEADING2) => Some(2)
      case Some(Keyword.THY_HEADING3) | Some(Keyword.PRF_HEADING3) => Some(3)
      case Some(Keyword.THY_HEADING4) | Some(Keyword.PRF_HEADING4) => Some(4)
      case Some(kind) if Keyword.theory(kind) => Some(5)
      case _ => None
    }
  }

  def heading_level(command: Command): Option[Int] =
    heading_level(command.name)


  /* token language */

  def scan(input: Reader[Char]): List[Token] =
  {
    Token.Parsers.parseAll(
        Token.Parsers.rep(Token.Parsers.token(lexicon, is_command)), input) match {
      case Token.Parsers.Success(tokens, _) => tokens
      case _ => error("Unexpected failure of tokenizing input:\n" + input.source.toString)
    }
  }

  def scan(input: CharSequence): List[Token] =
    scan(new CharSequenceReader(input))

  def scan_line(input: CharSequence, context: Scan.Line_Context): (List[Token], Scan.Line_Context) =
  {
    var in: Reader[Char] = new CharSequenceReader(input)
    val toks = new mutable.ListBuffer[Token]
    var ctxt = context
    while (!in.atEnd) {
      Token.Parsers.parse(Token.Parsers.token_line(lexicon, is_command, ctxt), in) match {
        case Token.Parsers.Success((x, c), rest) => { toks += x; ctxt = c; in = rest }
        case Token.Parsers.NoSuccess(_, rest) =>
          error("Unexpected failure of tokenizing input:\n" + rest.source.toString)
      }
    }
    (toks.toList, ctxt)
  }


  /* language context */

  def set_completion_context(context: Completion.Context): Outer_Syntax =
    new Outer_Syntax(keywords, lexicon, completion, context, has_tokens)

  def no_tokens: Outer_Syntax =
  {
    require(keywords.isEmpty && lexicon.isEmpty)
    new Outer_Syntax(
      completion = completion,
      completion_context = completion_context,
      has_tokens = false)
  }
}