diff -r b5eb7c688836 -r 740a0ca7e09b src/Pure/Isar/token.scala
--- a/src/Pure/Isar/token.scala	Sun Mar 15 19:48:49 2015 +0100
+++ b/src/Pure/Isar/token.scala	Sun Mar 15 20:35:47 2015 +0100
@@ -158,7 +158,9 @@
   object Pos
   {
     val none: Pos = new Pos(0, 0, "")
-    def file(file: String): Pos = new Pos(0, 0, file)
+    val start: Pos = new Pos(1, 1, "")
+    val offset: Pos = new Pos(0, 1, "")
+    def file(file: String): Pos = new Pos(1, 1, file)
   }
 
   final class Pos private[Token](
@@ -203,8 +205,8 @@
     def atEnd = tokens.isEmpty
   }
 
-  def reader(tokens: List[Token], file: String): Reader =
-    new Token_Reader(tokens, Pos.file(file))
+  def reader(tokens: List[Token], start: Token.Pos): Reader =
+    new Token_Reader(tokens, start)
 }