> But some people feel we need a more formal specification language > that goes beyond "key point compliance" or "requirements definition", > and some are using 2119 words in that role and like it. Having read specs like the Algol 68 report and ANSI X3.53-1976, the PL/I standard that's largely written in VDL, I have an extremely low opinion of specs that attempt to be very formal. The problem is not unlike the one with the fad for proofs of program correctness back in the 1970s and 1980s. Your formal thing ends up being in effect a large chunk of software, which will have just as many bugs as any other large chunk of software. The PL/I standard is famous for that; to implement it you both need to be able to decode the VDL and to know PL/I well enough to recognize the mistakes. What we really need to strive for is clear writing, which is not the same thing as formal writing. When you're writing clearly, the places where you'd need 2119 stuff would be where you want to emphasize that something that might seem optional or not a big deal is in fact important and mandatory or important and forbidden. R's, John