Improve code generation with aggregations

opengeode/AdaGenerator.py

@@ -468,13 +468,14 @@ package {process_name} is'''.format(process_name=process_name,
                 # - add a swich case on the corresponding substate
                 taste_template.append(u'-- this is a state aggregation')
                 for sub in aggregates[state]:
-                    for par in sub.mapping.viewkeys():
-                        if par in mapping[signame].viewkeys():
+                    if [a for a in sub.mapping.viewkeys()
+                            if a in mapping[signame].viewkeys()]:
                         taste_template.append(u'case '
                                               u'{ctxt}.{sub}{sep}state is'
                                               .format(ctxt=LPREFIX,
                                                      sub=sub.statename,
                                                      sep=UNICODE_SEP))
+                        for par in sub.mapping.viewkeys():
                             case_state(par)
                         taste_template.append('when others =>')
                         taste_template.append('null;')