1 files changed, 13 insertions, 7 deletions
diff --git a/stream.sml b/stream.sml
index 1755817..bc9048b 100644
--- a/stream.sml
+++ b/stream.sml
@@ -6,6 +6,7 @@ structure Stream :> STREAM = struct
   type fileInfo = fileId * string * string
 
   exception UngetcError
+  exception InvalidFileInfo
 
   fun ppos2str (pos, line, col) =
   let
@@ -56,12 +57,17 @@ structure Stream :> STREAM = struct
 
   fun getPosAfterCharRead (fid, _, off, _) = (fid, off - 1)
 
-  fun pos2ppos (_, pos) (_, fname, _, contents) =
-  let
-    val (line, col) = calcFilePos contents pos
-  in
-    (fname, line, SOME col)
-  end
+  fun pos2pposWithFI (id, pos) (id', fname, contents) =
+    if id <> id' then
+      raise InvalidFileInfo
+    else
+    let
+      val (line, col) = calcFilePos contents pos
+    in
+      (fname, line, SOME col)
+    end
+
+  fun pos2ppos pos stream = pos2pposWithFI pos (convert stream)
 
   fun pposWithoutCol (fname, line, SOME _) = (fname, line, NONE)
     | pposWithoutCol (_, _, NONE) = raise Unreachable
@@ -71,7 +77,7 @@ structure Stream :> STREAM = struct
   fun getSubstr startOff endOff (_, _, _, contents) =
       String.substring (contents, startOff, endOff - startOff)
 
-  fun streamInit fname =
+  fun create fname =
   let
     open TextIO