diff --git a/CMakeLists.txt b/CMakeLists.txt
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,29 +12,47 @@
   SET(LEMON_VERSION $ENV{LEMON_VERSION} CACHE STRING "LEMON version string.")
 ELSE()
   EXECUTE_PROCESS(
-    COMMAND ${PYTHON_EXECUTABLE} ./scripts/chg-len.py
+    COMMAND
+    hg log -r. --template "{latesttag}"
     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    OUTPUT_VARIABLE HG_REVISION_PATH
+    OUTPUT_VARIABLE HG_REVISION_TAG
     ERROR_QUIET
     OUTPUT_STRIP_TRAILING_WHITESPACE
   )
   EXECUTE_PROCESS(
-    COMMAND hg id -i
+    COMMAND
+    hg log -r. --template "{latesttagdistance}"
     WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
-    OUTPUT_VARIABLE HG_REVISION
+    OUTPUT_VARIABLE HG_REVISION_DIST
     ERROR_QUIET
     OUTPUT_STRIP_TRAILING_WHITESPACE
   )
-  IF(HG_REVISION STREQUAL "")
+  EXECUTE_PROCESS(
+    COMMAND
+    hg log -r. --template "{node|short}"
+    WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
+    OUTPUT_VARIABLE HG_REVISION_ID
+    ERROR_QUIET
+    OUTPUT_STRIP_TRAILING_WHITESPACE
+  )
+
+  IF(HG_REVISION_TAG STREQUAL "")
     SET(HG_REVISION_ID "hg-tip")
   ELSE()
-    IF(HG_REVISION_PATH STREQUAL "")
-      SET(HG_REVISION_ID ${HG_REVISION})
+    IF(HG_REVISION_TAG STREQUAL "null")
+      SET(HG_REVISION_TAG "trunk")
+    ELSEIF(HG_REVISION_TAG MATCHES "^r")
+      STRING(SUBSTRING ${HG_REVISION_TAG} 1 -1 HG_REVISION_TAG)
+    ENDIF()
+    IF(HG_REVISION_DIST STREQUAL "0")
+      SET(HG_REVISION ${HG_REVISION_TAG})
     ELSE()
-      SET(HG_REVISION_ID ${HG_REVISION_PATH}.${HG_REVISION})
+      SET(HG_REVISION
+	"${HG_REVISION_TAG}+${HG_REVISION_DIST}-${HG_REVISION_ID}")
     ENDIF()
   ENDIF()
-  SET(LEMON_VERSION ${HG_REVISION_ID} CACHE STRING "LEMON version string.")
+
+  SET(LEMON_VERSION ${HG_REVISION} CACHE STRING "LEMON version string.")
 ENDIF()
 
 SET(PROJECT_VERSION ${LEMON_VERSION})
diff --git a/scripts/chg-len.py b/scripts/chg-len.py
deleted file mode 100755
--- a/scripts/chg-len.py
+++ /dev/null
@@ -1,46 +0,0 @@
-#! /usr/bin/env python
-#
-# This file is a part of LEMON, a generic C++ optimization library.
-#
-# Copyright (C) 2003-2009
-# Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
-# (Egervary Research Group on Combinatorial Optimization, EGRES).
-#
-# Permission to use, modify and distribute this software is granted
-# provided that this copyright notice appears in all copies. For
-# precise terms see the accompanying LICENSE file.
-#
-# This software is provided "AS IS" with no warranty of any kind,
-# express or implied, and with no claim as to its suitability for any
-# purpose.
-
-import sys
-
-from mercurial import ui, hg
-from mercurial import util
-
-util.rcpath = lambda : []
-
-if len(sys.argv)>1 and sys.argv[1] in ["-h","--help"]:
-    print """
-This utility just prints the length of the longest path
-in the revision graph from revison 0 to the current one.
-"""
-    exit(0)
-
-u = ui.ui()
-r = hg.repository(u, ".")
-N = r.changectx(".").rev()
-lengths=[0]*(N+1)
-for i in range(N+1):
-    p=r.changectx(i).parents()
-    if p[0]:
-        p0=lengths[p[0].rev()]
-    else:
-        p0=-1
-    if len(p)>1 and p[1]:
-        p1=lengths[p[1].rev()]
-    else:
-        p1=-1
-    lengths[i]=max(p0,p1)+1
-print lengths[N]