stepalternatives
                  stepalternatives — Alternative steps in a procedure
stepalternatives ::=
(step+)| 
                         Name  | 
                     
                         Type  | 
                     
                         Default  | 
                  |||
| performance | 
                        
  | 
                     "required" | 
Most steps in a procedure
               are sequential: do the first, then the second, then the third. Sometimes
               procedures provide an explicit ordering: do step 7 next.
            
The stepalternatives element was added to
               support the semantics of alternative steps: perform exactly one of the
               following steps. The reader is presumably given some criteria for deciding
               which one to choose, but the significant difference is that only one of
               the steps is performed.
            
Performance specifies whether one
                        of the step alternatives must be performed or if the whole
                        set is optional. (In no case is more than one alternative performed.)