code: def p_fromtable(self,t):
      
      if len(t)==6: t[0]=AliasX(t[2],t[5])
      elif len(t)==2: t[0]=t[1]
      else: raise NotImplementedError('unk_len',len(t)) # pragma: no cover
docs: fromtable : NAME
                   | aliasx
                   | '(' selectx ')' kw_as NAME