diff --git a/src/backend/string_utils.cc b/src/backend/string_utils.cc
index 876f235..4d56225 100644
--- a/src/backend/string_utils.cc
+++ b/src/backend/string_utils.cc
@@ -46,8 +46,13 @@ namespace sgpem
   T
   string_to(const ustring& str) throw(domain_error)
   {
+    if (tokenize(str).size() != 1)
+      throw domain_error(_("too few or too many tokens"));
+
     istringstream iss(str);
     T result;
+    
+    iss.exceptions(ios_base::failbit | ios_base::badbit);
 
     try
     {
@@ -58,6 +63,13 @@ namespace sgpem
       throw domain_error(e.what());
     }
 
+    // disable exceptions, otherwise peek() will throw them!
+    // how useless!!!
+//    iss.exceptions(ios_base::goodbit);
+
+//    if (iss.peek() != istringstream::traits_type::eof())
+//      throw domain_error(_("incorrect number format"));
+
     return result;
   }
 
@@ -71,7 +83,24 @@ namespace sgpem
 
     istringstream iss(str);
     bool value;
-    iss >> value;
+    
+    iss.exceptions(ios_base::failbit | ios_base::badbit);
+
+    try
+    {
+      iss >> boolalpha >> value;
+    }
+    catch (ios_base::failure e)
+    {
+      throw domain_error(e.what());
+    }
+
+    // disable exceptions, otherwise peek() will throw them!
+    // how useless!!!
+//    iss.exceptions(ios_base::goodbit);
+
+//    if (iss.peek() != istringstream::traits_type::eof())
+//      throw domain_error(_("incorrect boolean"));
     return value;
   }