diff --git a/src/db/db/dbBox.h b/src/db/db/dbBox.h
index ea3e1648e..a3319fffb 100644
--- a/src/db/db/dbBox.h
+++ b/src/db/db/dbBox.h
@@ -860,8 +860,10 @@ template <class C, class R>
 inline box<C, R> &
 box<C, R>::move (const vector<C> &p)
 {
-  m_p1 += p;
-  m_p2 += p;
+  if (! empty ()) {
+    m_p1 += p;
+    m_p2 += p;
+  }
   return *this;
 }
 
@@ -869,8 +871,10 @@ template <class C, class R>
 inline box<C, R> &
 box<C, R>::enlarge (const vector<C> &p)
 {
-  m_p1 -= p;
-  m_p2 += p;
+  if (! empty ()) {
+    m_p1 -= p;
+    m_p2 += p;
+  }
   return *this;
 }
 
diff --git a/src/db/db/dbGDS2WriterBase.cc b/src/db/db/dbGDS2WriterBase.cc
index cd6df2a99..d8dd26614 100644
--- a/src/db/db/dbGDS2WriterBase.cc
+++ b/src/db/db/dbGDS2WriterBase.cc
@@ -831,15 +831,8 @@ GDS2WriterBase::write_properties (const db::Layout &layout, db::properties_id_ty
     const tl::Variant &name = layout.properties_repository ().prop_name (p->first);
 
     long attr = -1;
-    if (name.is_long ()) {
+    if (name.can_convert_to_long ()) {
       attr = name.to_long ();
-    } else if (name.is_a_string ()) {
-      //  string names representing a number are converted to numeric property names
-      tl::Extractor ex (name.to_string ());
-      long a = 0;
-      if (ex.try_read (a) && ex.at_end ()) {
-        attr = a;
-      }
     }
 
     if (attr >= 0 && attr < 65535) {
diff --git a/src/db/db/dbOASISWriter.cc b/src/db/db/dbOASISWriter.cc
index ba2e2546e..4f41cde4b 100644
--- a/src/db/db/dbOASISWriter.cc
+++ b/src/db/db/dbOASISWriter.cc
@@ -55,7 +55,9 @@ make_gds_property (const tl::Variant &name)
 {
   //  We write S_GDS_PROPERTY properties, because that is the only way to write properties
   //  with numerical keys
-  return (name.is_long () && (name.to_long () < 0x8000 || name.to_long () >= 0)) ||
+  return (name.is_longlong () && name.to_longlong () < 0x8000 && name.to_longlong () >= 0) ||
+         (name.is_ulonglong () && name.to_ulonglong () < 0x8000) ||
+         (name.is_long () && name.to_long () < 0x8000 && name.to_long () >= 0) ||
          (name.is_ulong () && name.to_ulong () < 0x8000);
 }
 
diff --git a/src/db/unit_tests/dbBox.cc b/src/db/unit_tests/dbBox.cc
index 071d04ab5..5a3396c7b 100644
--- a/src/db/unit_tests/dbBox.cc
+++ b/src/db/unit_tests/dbBox.cc
@@ -41,12 +41,19 @@ TEST(2)
 
   EXPECT_EQ (b.moved (db::Vector (10, 20)), db::Box (110, 20, 10, 220));
   EXPECT_EQ (b.enlarged (db::Vector (10, 20)), db::Box (-10, -20, 110, 220));
+  EXPECT_EQ (empty.moved (db::Vector (10, 20)).empty (), true);
+  EXPECT_EQ (empty.enlarged (db::Vector (10, 20)).empty (), true);
   EXPECT_EQ (b + db::Box (-10, 20, 100, 200), db::Box (-10, 0, 100, 200));
   EXPECT_EQ (b + db::Box (-10, -20, 100, -10), db::Box (-10, -20, 100, 200));
   EXPECT_EQ (b + db::Box (110, 220, 120, 250), db::Box (0, 0, 120, 250));
   EXPECT_EQ (b & db::Box (110, 220, 120, 250), empty);
   EXPECT_EQ (b & db::Box (50, 100, 120, 250), db::Box (50, 100, 100, 200));
   EXPECT_EQ (b & db::Box (50, 100, 60, 120), db::Box (50, 100, 60, 120));
+
+  empty.move (db::Vector (10, 20));
+  EXPECT_EQ (empty == db::Box (), true);
+  empty.enlarge (db::Vector (10, 20));
+  EXPECT_EQ (empty == db::Box (), true);
 }
 
 TEST(3) 
diff --git a/src/tl/tl/tlString.cc b/src/tl/tl/tlString.cc
index 52d7f6715..aaf8ab3a0 100644
--- a/src/tl/tl/tlString.cc
+++ b/src/tl/tl/tlString.cc
@@ -831,186 +831,160 @@ tl::Extractor::read_quoted (std::string &value)
   return *this;
 }
 
-bool 
+namespace
+{
+  template <class T> struct overflow_msg_func;
+
+  template <> struct overflow_msg_func<long long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on long long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned long long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned long long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned long>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned long integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<int>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on integer"));
+    }
+  };
+
+  template <> struct overflow_msg_func<unsigned int>
+  {
+    std::string operator() () const
+    {
+      return tl::to_string (QObject::tr ("Range overflow on unsigned integer"));
+    }
+  };
+}
+
+template <class T> bool
+tl::Extractor::try_read_signed_int (T &value)
+{
+  if (! *skip ()) {
+    return false;
+  }
+
+  bool minus = false;
+  if (*m_cp == '-') {
+    minus = true;
+    ++m_cp;
+  } else if (*m_cp == '+') {
+    ++m_cp;
+  }
+
+  if (! isdigit (*m_cp)) {
+    return false;
+  }
+
+  value = 0;
+  while (isdigit (*m_cp)) {
+    if (value > std::numeric_limits<T>::max () / 10) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value *= 10;
+    if (value > std::numeric_limits<T>::max () - (*m_cp - '0')) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value += (*m_cp - '0');
+    ++m_cp;
+  }
+
+  if (minus) {
+    value = -value;
+  }
+
+  return true;
+}
+
+template <class T> bool
+tl::Extractor::try_read_unsigned_int (T &value)
+{
+  if (! *skip ()) {
+    return false;
+  }
+
+  if (! isdigit (*m_cp)) {
+    return false;
+  }
+
+  value = 0;
+  while (isdigit (*m_cp)) {
+    if (value > std::numeric_limits<T>::max () / 10) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value *= 10;
+    if (value > std::numeric_limits<T>::max () - (*m_cp - '0')) {
+      throw tl::Exception (overflow_msg_func<T> () ());
+    }
+    value += (*m_cp - '0');
+    ++m_cp;
+  }
+
+  return true;
+}
+
+bool
 tl::Extractor::try_read (unsigned int &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
-tl::Extractor::try_read (int &value)
-{
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
-}
-
-bool 
+bool
 tl::Extractor::try_read (unsigned long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
+bool
 tl::Extractor::try_read (unsigned long long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on unsigned long long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  return true;
+  return try_read_unsigned_int (value);
 }
 
-bool 
+bool
+tl::Extractor::try_read (int &value)
+{
+  return try_read_signed_int (value);
+}
+
+bool
 tl::Extractor::try_read (long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
+  return try_read_signed_int (value);
 }
 
-bool 
+bool
 tl::Extractor::try_read (long long &value)
 {
-  if (! *skip ()) {
-    return false;
-  } 
-
-  bool minus = false;
-  if (*m_cp == '-') {
-    minus = true;
-    ++m_cp;
-  } else if (*m_cp == '+') {
-    ++m_cp;
-  }
-
-  if (! isdigit (*m_cp)) {
-    return false;
-  } 
-
-  value = 0;
-  while (isdigit (*m_cp)) {
-    if ((value * 10) / 10 != value) {
-      throw tl::Exception (tl::to_string (QObject::tr ("Range overflow on long long integer")));
-    }
-    value *= 10;
-    value += (*m_cp - '0');
-    ++m_cp;
-  }
-
-  if (minus) {
-    value = -value;
-  }
-
-  return true;
+  return try_read_signed_int (value);
 }
-
 bool 
 tl::Extractor::try_read (double &value)
 {
diff --git a/src/tl/tl/tlString.h b/src/tl/tl/tlString.h
index 718b2c169..11c8b05a4 100644
--- a/src/tl/tl/tlString.h
+++ b/src/tl/tl/tlString.h
@@ -732,6 +732,9 @@ public:
   }
 
 private:
+  template <class T> bool try_read_signed_int (T &value);
+  template <class T> bool try_read_unsigned_int (T &value);
+
   const char *m_cp;
   std::string m_str;
 };
diff --git a/src/tl/tl/tlVariant.cc b/src/tl/tl/tlVariant.cc
index d223ab537..322e17820 100644
--- a/src/tl/tl/tlVariant.cc
+++ b/src/tl/tl/tlVariant.cc
@@ -894,18 +894,18 @@ normalized_type (Variant::type type)
   case Variant::t_short:
   case Variant::t_int:
   case Variant::t_long:
-    return Variant::t_long;
+  case Variant::t_longlong:
+    return Variant::t_longlong;
   case Variant::t_uchar:
   case Variant::t_ushort:
   case Variant::t_uint:
   case Variant::t_ulong:
-    return Variant::t_ulong;
+  case Variant::t_ulonglong:
+    return Variant::t_ulonglong;
   case Variant::t_stdstring:
   case Variant::t_string:
     return Variant::t_string;
   default:
-  case Variant::t_longlong:
-  case Variant::t_ulonglong:
 #if defined(HAVE_64BIT_COORD)
   case Variant::t_int128:
 #endif
@@ -1195,8 +1195,12 @@ Variant::can_convert_to_ulonglong () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      unsigned long long ll;
-      return ex.try_read (ll) && ex.at_end ();
+      try {
+        unsigned long long ll;
+        return ex.try_read (ll) && ex.at_end ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1236,8 +1240,12 @@ Variant::can_convert_to_longlong () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      long long ll;
-      return ex.try_read (ll) && ex.at_end ();
+      try {
+        long long ll;
+        return ex.try_read (ll) && ex.at_end ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1257,9 +1265,9 @@ Variant::can_convert_to_ulong () const
     return m_var.m_int128 <= __int128 (std::numeric_limits<unsigned long long>::max ()) && m_var.m_int128 >= __int128 (std::numeric_limits<unsigned long long>::min ());
 #endif
   case t_longlong:
-    return m_var.m_longlong >= 0 && m_var.m_longlong < (long long) std::numeric_limits<unsigned long>::max ();
+    return m_var.m_longlong >= 0 && (unsigned long long) m_var.m_longlong <= (unsigned long long) std::numeric_limits<unsigned long>::max ();
   case t_ulonglong:
-    return m_var.m_ulonglong < (unsigned long long) std::numeric_limits<unsigned long>::max ();
+    return m_var.m_ulonglong <= (unsigned long long) std::numeric_limits<unsigned long>::max ();
   case t_ulong:
   case t_bool:
   case t_uchar:
@@ -1283,8 +1291,12 @@ Variant::can_convert_to_ulong () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      unsigned long l;
-      return ex.try_read (l) && ex.at_end ();
+      try {
+        unsigned long l;
+        return ex.try_read (l) && ex.at_end ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1326,8 +1338,12 @@ Variant::can_convert_to_long () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      long l;
-      return ex.try_read (l) && ex.at_end ();
+      try {
+        long l;
+        return ex.try_read (l) && ex.at_end ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1371,8 +1387,12 @@ Variant::can_convert_to_int () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      long l;
-      return ex.try_read (l) && ex.at_end () && l >= (long) std::numeric_limits<int>::min () && l <= (long) std::numeric_limits<int>::max ();
+      try {
+        long l;
+        return ex.try_read (l) && ex.at_end () && l >= (long) std::numeric_limits<int>::min () && l <= (long) std::numeric_limits<int>::max ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1416,8 +1436,12 @@ Variant::can_convert_to_uint () const
   case t_stdstring:
     {
       tl::Extractor ex (to_string ());
-      long l;
-      return ex.try_read (l) && ex.at_end () && l >= (long) std::numeric_limits<int>::min () && l <= (long) std::numeric_limits<int>::max ();
+      try {
+        long l;
+        return ex.try_read (l) && ex.at_end () && l >= (long) std::numeric_limits<int>::min () && l <= (long) std::numeric_limits<int>::max ();
+      } catch (...) {
+        return false;
+      }
     }
   default:
     return false;
@@ -1684,7 +1708,7 @@ Variant::to_ulonglong () const
     return m_var.m_long;
 #if defined(HAVE_64BIT_COORD)
   } else if (m_type == t_int128) {
-    return m_var.m_int128;
+    return (unsigned long long) m_var.m_int128;
 #endif
   } else if (m_type == t_ulonglong) {
     return m_var.m_ulonglong;
@@ -1738,7 +1762,7 @@ Variant::to_longlong () const
     return m_var.m_longlong;
 #if defined(HAVE_64BIT_COORD)
   } else if (m_type == t_int128) {
-    return m_var.m_int128;
+    return (long long) m_var.m_int128;
 #endif
   } else if (m_type == t_bool) {
     return m_var.m_bool;
@@ -1783,12 +1807,12 @@ Variant::to_ulong () const
   } else if (m_type == t_long) {
     return m_var.m_long;
   } else if (m_type == t_ulonglong) {
-    return m_var.m_ulonglong;
+    return (unsigned long) (m_var.m_ulonglong);
   } else if (m_type == t_longlong) {
-    return m_var.m_longlong;
+    return (unsigned long) (m_var.m_longlong);
 #if defined(HAVE_64BIT_COORD)
   } else if (m_type == t_int128) {
-    return m_var.m_int128;
+    return (unsigned long) (m_var.m_int128);
 #endif
   } else if (m_type == t_bool) {
     return m_var.m_bool;
@@ -1833,12 +1857,12 @@ Variant::to_long () const
   } else if (m_type == t_long) {
     return m_var.m_long;
   } else if (m_type == t_ulonglong) {
-    return m_var.m_ulonglong;
+    return long (m_var.m_ulonglong);
   } else if (m_type == t_longlong) {
-    return m_var.m_longlong;
+    return long (m_var.m_longlong);
 #if defined(HAVE_64BIT_COORD)
   } else if (m_type == t_int128) {
-    return m_var.m_int128;
+    return long (m_var.m_int128);
 #endif
   } else if (m_type == t_bool) {
     return m_var.m_bool;
diff --git a/src/tl/unit_tests/tlVariant.cc b/src/tl/unit_tests/tlVariant.cc
index 6fa511411..5a8b688d7 100644
--- a/src/tl/unit_tests/tlVariant.cc
+++ b/src/tl/unit_tests/tlVariant.cc
@@ -113,7 +113,9 @@ TEST(1)
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (v.is_char (), false);
   EXPECT_EQ (v.is_long (), false);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "nil");
   vv = v;
@@ -135,10 +137,13 @@ TEST(1)
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (v.is_ulong (), true);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_long (), false);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "#u1");
   EXPECT_EQ (v.to_long (), 1l);
+  EXPECT_EQ (v.to_longlong (), 1l);
   EXPECT_EQ (v.is<unsigned long> (), true);
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (vv == v, false);
@@ -167,11 +172,14 @@ TEST(1)
   EXPECT_EQ (v.is<unsigned long> (), false);
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (v.is_ulong (), true);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_long (), false);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "#u2");
   EXPECT_EQ (v.to_long (), 2l);
+  EXPECT_EQ (v.to_longlong (), 2l);
   EXPECT_EQ (vv == v, false);
   EXPECT_EQ (vv != v, true);
   vv = v;
@@ -194,7 +202,9 @@ TEST(1)
   EXPECT_EQ (v.is_list (), false);
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_long (), true);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (v.is<unsigned long> (), false);
   EXPECT_EQ (v.is<int> (), true);
@@ -202,6 +212,7 @@ TEST(1)
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "#1");
   EXPECT_EQ (v.to_long (), 1l);
+  EXPECT_EQ (v.to_longlong (), 1l);
   EXPECT_EQ (vv == v, false);
   EXPECT_EQ (vv != v, true);
   vv = v;
@@ -239,6 +250,7 @@ TEST(1)
   EXPECT_EQ (v.is<signed char> (), false);
   EXPECT_EQ (v.to_parsable_string (), "#2");
   EXPECT_EQ (v.to_long (), 2l);
+  EXPECT_EQ (v.to_longlong (), 2l);
   EXPECT_EQ (v.to_double (), 2.0);
   EXPECT_EQ (v.to_float (), 2.0);
   EXPECT_EQ (vv == v, false);
@@ -261,7 +273,9 @@ TEST(1)
   EXPECT_EQ (v.is_list (), false);
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_long (), false);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_char (), false);
   EXPECT_EQ (v.is_double (), true);
   EXPECT_EQ (v.is<long> (), false);
@@ -278,6 +292,10 @@ TEST(1)
   EXPECT_EQ (v.to_parsable_string (), "##5");
   EXPECT_EQ (v.to_double (), 5.0);
   EXPECT_EQ (v.to_float (), 5.0);
+  EXPECT_EQ (v.to_long (), 5);
+  EXPECT_EQ (v.to_ulong (), 5u);
+  EXPECT_EQ (v.to_longlong (), 5);
+  EXPECT_EQ (v.to_ulonglong (), 5u);
   EXPECT_EQ (vv == v, false);
   EXPECT_EQ (vv != v, true);
   vv = v;
@@ -300,7 +318,9 @@ TEST(1)
   EXPECT_EQ (v.is_list (), false);
   EXPECT_EQ (v.is_cstring (), false);
   EXPECT_EQ (v.is_long (), false);
+  EXPECT_EQ (v.is_longlong (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), true);
   EXPECT_EQ (v.is<long> (), false);
   EXPECT_EQ (v.is<unsigned long> (), false);
@@ -317,6 +337,10 @@ TEST(1)
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (v.to_parsable_string (), "##5");
   EXPECT_EQ (v.to_double (), 5.0);
+  EXPECT_EQ (v.to_long (), 5);
+  EXPECT_EQ (v.to_longlong (), 5);
+  EXPECT_EQ (v.to_ulong (), 5u);
+  EXPECT_EQ (v.to_ulonglong (), 5u);
   EXPECT_EQ (*(double *)v.native_ptr (), 5.0);
   EXPECT_EQ (vv == v, true);
   EXPECT_EQ (vv != v, false);
@@ -365,6 +389,8 @@ TEST(1)
   EXPECT_EQ (v.is_char (), false);
   EXPECT_EQ (v.is_long (), true);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_longlong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.to_parsable_string (), "#2");
   vv = v;
@@ -440,6 +466,8 @@ TEST(1)
   EXPECT_EQ (v.is_cstring (), true);
   EXPECT_EQ (v.is_long (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_longlong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (v.to_parsable_string (), "'hal\\'l\"o'");
@@ -470,6 +498,8 @@ TEST(1)
   EXPECT_EQ (v.is_stdstring (), false);
   EXPECT_EQ (v.is_long (), false);
   EXPECT_EQ (v.is_ulong (), false);
+  EXPECT_EQ (v.is_longlong (), false);
+  EXPECT_EQ (v.is_ulonglong (), false);
   EXPECT_EQ (v.is_double (), false);
   EXPECT_EQ (v.is_id (), false);
   EXPECT_EQ (std::string (v.to_string ()), "hal'l\"o");
@@ -810,6 +840,217 @@ TEST(3)
   EXPECT_EQ (v2 < v2, false);
 }
 
+//  can_convert_to
+TEST(4)
+{
+  tl::Variant v;
+  v = tl::Variant (1);
+  EXPECT_EQ (v.can_convert_to_char (), true);
+  EXPECT_EQ (v.can_convert_to_uchar (), true);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), true);
+  EXPECT_EQ (v.can_convert_to_ushort (), true);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), true);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), true);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant (-1);
+  EXPECT_EQ (v.can_convert_to_char (), true);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), true);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), false);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), false);
+
+  v = tl::Variant (1000);
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), true);
+  EXPECT_EQ (v.can_convert_to_ushort (), true);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), true);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), true);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant ("1000");
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), true);
+  EXPECT_EQ (v.can_convert_to_ushort (), true);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), true);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), true);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant (100000);
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), true);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), true);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant (10000000000ll);
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), false);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  if (sizeof (long) == 4) {
+    EXPECT_EQ (v.can_convert_to_long (), false);
+    EXPECT_EQ (v.can_convert_to_ulong (), false);
+  } else {
+    EXPECT_EQ (v.can_convert_to_long (), true);
+    EXPECT_EQ (v.can_convert_to_ulong (), true);
+  }
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant (0.5);
+  EXPECT_EQ (v.can_convert_to_char (), true);
+  EXPECT_EQ (v.can_convert_to_uchar (), true);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), true);
+  EXPECT_EQ (v.can_convert_to_ushort (), true);
+  EXPECT_EQ (v.can_convert_to_int (), true);
+  EXPECT_EQ (v.can_convert_to_uint (), true);
+  EXPECT_EQ (v.can_convert_to_long (), true);
+  EXPECT_EQ (v.can_convert_to_ulong (), true);
+  EXPECT_EQ (v.can_convert_to_longlong (), true);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), true);
+
+  v = tl::Variant ("100000000000000000000");
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), true);
+  EXPECT_EQ (v.can_convert_to_float (), true);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), false);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  EXPECT_EQ (v.can_convert_to_long (), false);
+  EXPECT_EQ (v.can_convert_to_ulong (), false);
+  EXPECT_EQ (v.can_convert_to_longlong (), false);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), false);
+
+  v = tl::Variant ("1000x");
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), false);
+  EXPECT_EQ (v.can_convert_to_float (), false);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), false);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  EXPECT_EQ (v.can_convert_to_long (), false);
+  EXPECT_EQ (v.can_convert_to_ulong (), false);
+  EXPECT_EQ (v.can_convert_to_longlong (), false);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), false);
+
+  v = tl::Variant ("");
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), false);
+  EXPECT_EQ (v.can_convert_to_float (), false);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), false);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  EXPECT_EQ (v.can_convert_to_long (), false);
+  EXPECT_EQ (v.can_convert_to_ulong (), false);
+  EXPECT_EQ (v.can_convert_to_longlong (), false);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), false);
+
+  v = tl::Variant ("x");
+  EXPECT_EQ (v.can_convert_to_char (), false);
+  EXPECT_EQ (v.can_convert_to_uchar (), false);
+  EXPECT_EQ (v.can_convert_to_double (), false);
+  EXPECT_EQ (v.can_convert_to_float (), false);
+  EXPECT_EQ (v.can_convert_to_short (), false);
+  EXPECT_EQ (v.can_convert_to_ushort (), false);
+  EXPECT_EQ (v.can_convert_to_int (), false);
+  EXPECT_EQ (v.can_convert_to_uint (), false);
+  EXPECT_EQ (v.can_convert_to_long (), false);
+  EXPECT_EQ (v.can_convert_to_ulong (), false);
+  EXPECT_EQ (v.can_convert_to_longlong (), false);
+  EXPECT_EQ (v.can_convert_to_ulonglong (), false);
+}
+
+//  Variants as key maps
+TEST(5)
+{
+  std::map<tl::Variant, int> m;
+
+  //  there are four categories which are separated:
+  //    int
+  //    unsigned int
+  //    float (downwards compatible with int and unsigned int)
+  //    string
+  m.insert (std::make_pair (tl::Variant (1), 17));
+  m.insert (std::make_pair (tl::Variant ((unsigned int) 2), 42));
+  m.insert (std::make_pair (tl::Variant ("3"), 41));
+  m.insert (std::make_pair (tl::Variant (2.5), -17));
+
+  //  int category
+  EXPECT_EQ (m [1], 17);
+  EXPECT_EQ (m [(char) 1], 17);
+  EXPECT_EQ (m [(short) 1], 17);
+  EXPECT_EQ (m [(int) 1], 17);
+  EXPECT_EQ (m [(long long) 1], 17);
+  EXPECT_EQ (m [1.0], 17);
+  //  non-members of that category
+  EXPECT_EQ (m [1.25], 0);
+  EXPECT_EQ (m [(unsigned int) 1], 0);
+  EXPECT_EQ (m ["1"], 0);
+
+  //  unsigned int category
+  EXPECT_EQ (m [(unsigned char) 2], 42);
+  EXPECT_EQ (m [(unsigned short) 2], 42);
+  EXPECT_EQ (m [(unsigned int) 2], 42);
+  EXPECT_EQ (m [(unsigned long long) 2], 42);
+  EXPECT_EQ (m [2.0], 42);
+  //  non-members of that category
+  EXPECT_EQ (m [2.25], 0);
+  EXPECT_EQ (m [2], 0);
+  EXPECT_EQ (m ["2"], 0);
+
+  //  float category
+  EXPECT_EQ (m [2.5], -17);
+  EXPECT_EQ (m [2.5001], 0);
+
+  //  string category
+  EXPECT_EQ (m ["3"], 41);
+  EXPECT_EQ (m [" 3"], 0);
+}
+
 }
 
 
diff --git a/testdata/python/dbLayoutTest.py b/testdata/python/dbLayoutTest.py
index b9baad341..4377479f8 100644
--- a/testdata/python/dbLayoutTest.py
+++ b/testdata/python/dbLayoutTest.py
@@ -19,6 +19,7 @@
 import pya
 import unittest
 import sys
+import os
 
 class DBLayoutTest(unittest.TestCase):
 
@@ -1104,6 +1105,53 @@ class DBLayoutTest(unittest.TestCase):
 
     ly._destroy()
 
+  # Bug #109
+  def test_bug109(self):
+
+    testtmp = os.getenv("TESTTMP_WITH_NAME", os.getenv("TESTTMP", "."))
+    
+    file_gds = os.path.join(testtmp, "bug109.gds")
+    file_oas = os.path.join(testtmp, "bug109.oas")
+
+    ly = pya.Layout()
+    top = ly.create_cell("TOP")
+    l1 = ly.layer(1, 0)
+    shape = top.shapes(l1).insert(pya.Box(0, 10, 20, 30))
+    shape.set_property(2, "hello, world")
+    shape.set_property("42", "the answer")
+
+    ly.write(file_gds)
+    ly.write(file_oas)
+
+    ly2 = pya.Layout()
+    ly2.read(file_gds)
+    l2 = ly2.layer(1, 0)
+    shape = None
+    for s in ly2.top_cell().shapes(l2).each():
+      shape = s
+    self.assertEqual(shape.property(2), "hello, world")
+    self.assertEqual(shape.property("2"), None)
+    self.assertEqual(shape.property(2.0), "hello, world")
+    self.assertEqual(shape.property(22), None)
+    self.assertEqual(shape.property(42), "the answer")
+    self.assertEqual(shape.property("42"), None)
+    self.assertEqual(shape.property(42.0), "the answer")
+
+    ly2 = pya.Layout()
+    ly2.read(file_oas)
+    l2 = ly2.layer(1, 0)
+    shape = None
+    for s in ly2.top_cell().shapes(l2).each():
+      shape = s
+    self.assertEqual(shape.property(2), "hello, world")
+    self.assertEqual(shape.property("2"), None)
+    self.assertEqual(shape.property(2.0), "hello, world")
+    self.assertEqual(shape.property(22), None)
+    self.assertEqual(shape.property("42"), "the answer")
+    self.assertEqual(shape.property(42), None)
+    self.assertEqual(shape.property(42.0), None)
+
+
 # run unit tests
 if __name__ == '__main__':
   suite = unittest.TestLoader().loadTestsFromTestCase(DBLayoutTest)