Re: EBNF

[Akim Demaille]

> > sometimes I really feel like writing rules like this:
> >
> > Rule: (A | B) C D
> >
> > Which would allow A C D or B C D. What is the reason to that such  
> > constructs
> > are not possible?
>
> Simply because nobody has implemented it. I think some grads at  
> Berkeley made a Bison version with such constructs.

Well, it is far from being "simply".  Can you tell me what is $1 here?
And what do you do in the following case?

         options: ( (opt1 | opt2) (',' (opt1 | opt2))* ) ?

The question mark is part of the rule, not of my text body.