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Puzzling syntax


I've been looking at the LSL 2.3 Reference Grammar and I'm puzzled by
the syntax for a "consequences":

    consequences ::= IMPLIES 
                     {  traitRef*, genPartition* eqPart
		      | [traitRef+, genPartition+] eqSeq }
                     conversion*

As I read this the consequences clause 

1.  implies
       Container
       a == b

is syntactically illegal -- because after a traitRef the "equals"
keyword cannot be omitted unless there also occurs at least one
genPartition.  The situation could be repaired by omitting the
traitRef 

2.  implies
       a == b

or by adding the "equations" keyword

3.  implies
       Container
    equations
       a == b

or by sticking in a genPartition

4.  implies
       Container
       S generated by f,g
       a == b

This rule strikes me as peculiar and unnatural.  Would anything useful
be lost by simplifying the syntax to

    consequences ::= IMPLIES 
                       traitRef*, genPartition* eqPart
                       conversion*

After this simplification only 3 would be legal and the user who
wanted to express the meaning of 2 would have to use, instead

2'.  implies
       equations
         a == b

It's hard to claim that this is unnacceptably prolix, given that the
same maneuver is required in a propPart:

     asserts
       equations
         a == b

The simplification would make the syntax of consequences a natural
generalization of that for propPart:

   propPart      ::= ASSERTS
                       genPartition* eqPart

The current rules strike me as so odd that I figure there must be some
good reason for it that I'm missing.

- David Guaspari
  davidg@oracorp.com