Strict mode parameter validation.

src/scanner-base.h

Index: src/scanner-base.h
diff --git a/src/scanner-base.h b/src/scanner-base.h
index 1024ad18582e3c078793d2295fe3cb8a92d23b18..96145b9c2dbd4420a0ecfc25a68960823a511385 100644
--- a/src/scanner-base.h
+++ b/src/scanner-base.h
@@ -271,10 +271,19 @@ class Scanner {
   struct Location {
     Location(int b, int e) : beg_pos(b), end_pos(e) { }
     Location() : beg_pos(0), end_pos(0) { }
+
+    bool IsValid() const {
+      return beg_pos >= 0 && end_pos >= 0;

[Lasse Reichstein, 2011/01/25 13:03:55]

How about ... && end_pos >= beg_pos;
Seems more "valid" to me :)

[Martin Maly, 2011/01/25 17:21:25]

Done. Using beg_pos >= 0 && end_pos >= beg_pos

because end_pos >= beg_pos >= 0 ===> end_pos >= 0

+    }
+
     int beg_pos;
     int end_pos;
   };
 
+  static Location NoLocation() {
+    return Location(-1, -1);
+  }
+
   // Returns the location information for the current token
   // (the token returned by Next()).
   Location location() const { return current_.location; }