src/Pure/Isar/outer_syntax.scala
2010-05-17 ago renamed class Outer_Lex to Token and Token_Kind to Token.Kind;
2010-05-15 ago renamed Outer_Keyword to Keyword (in Scala);
2010-01-05 ago tuned message;
2009-12-22 ago renamed class Outer_Keyword to Outer_Syntax;