* src/misc/modgray.hh, src/misc/modgray.cc: New files.

* src/misc/Makefile.am (libmisc_la_SOURCES, misc_HEADERS): Add them.
* wrap/python/spot.i: Activate directors, and interface modgray.hh.
* wrap/python/tests/modgray.py: New file.
* wrap/python/tests/Makefile.am (TESTS): Add it.

wrap/python/tests/Makefile.am

@@ -33,4 +33,5 @@ TESTS = \
   bddnqueen.py \
   ltl2tgba.test \
   interdep.py \
-  minato.py
+  minato.py \
+  modgray.py

wrap/python/tests/modgray.py

@@ -0,0 +1,58 @@
+# -*- mode: python; coding: iso-8859-1 -*-
+# Copyright (C) 2004  Laboratoire d'Informatique de Paris 6 (LIP6),
+# département Systèmes Répartis Coopératifs (SRC), Université Pierre
+# et Marie Curie.
+#
+# This file is part of Spot, a model checking library.
+#
+# Spot is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# Spot is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+# License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Spot; see the file COPYING.  If not, write to the Free
+# Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+# 02111-1307, USA.
+
+import ltihooks
+import spot
+
+class test(spot.loopless_modular_mixed_radix_gray_code):
+    def __init__(self, lim):
+        spot.loopless_modular_mixed_radix_gray_code.__init__(self, len(lim))
+        self.msg = list(lim)
+        self.lim = list(lim)
+
+    def a_first(self, j):
+        self.msg[j] = 'a'
+
+    def a_next(self, j):
+        self.msg[j] = chr(1 + ord(self.msg[j]))
+
+    def a_last(self, j):
+        return self.msg[j] == self.lim[j]
+
+    def run(self):
+        self.first()
+        res = []
+        while not self.done():
+            m = "".join(self.msg)
+            res.append(m)
+            print m
+            self.next()
+        return res
+
+
+t = test("acbb")
+
+expected = [ 'aaaa', 'abaa', 'acaa', 'acba',
+             'aaba', 'abba', 'abbb', 'acbb',
+             'aabb', 'aaab', 'abab', 'acab' ]
+
+assert t.run() == expected