804             mainvars = []

   804             mainvars = []

   805             if 'S' in defined:

   805             if 'S' in defined:

   806                 mainvars.append('S')

   806                 mainvars.append('S')

   807             if 'O' in defined:

   807             if 'O' in defined:

   808                 mainvars.append('O')

   808                 mainvars.append('O')

   809             if not mainvars:

   811             if not mainvars:

   810                 raise Exception('unable to guess selection variables')

   812                 raise Exception('unable to guess selection variables')

   811             mainvars = ','.join(mainvars)

   813             mainvars = ','.join(mainvars)

   812         RQLExpression.__init__(self, expression, mainvars, eid)

   814         RQLExpression.__init__(self, expression, mainvars, eid)

   813 

   815