leader/follower support

examples/Hangman/example.py

@@ -118,7 +118,7 @@ def main():
         proposal = ProposalOption('guess{}'.format(idx),
                                   'Guess {}'.format(idx),
                                   requires=requires,
-                                  properties=('positional',))
+                                  properties=('positional', 'mandatory'))
         #FIXME maximum recursion ...
         #if proposals:
         #    proposal.impl_add_consistency('not_equal', proposals[0])
@@ -150,7 +150,7 @@ def main():
     config.property.read_write()
     try:
         parser = TiramisuCmdlineParser(config)
-        parser.parse_args()
+        parser.parse_args(valid_mandatory=False)
     except ValueError:
         # if no more suggestion
         pass