[vorbis-dev] Xiph Magic

[Beni Cherniavsky]

J C Fitzgerald wrote on 2003-07-18:

> On Thu, Jul 17, 2003 at 03:36:06PM +0300, Beni Cherniavsky wrote:
> >
> > I'm quite unsure of this as the spec is *very* explicit on this.
>   ...
> > The only other
> > significant implementations are from-the-spec ones written to check
> > how clear is the spec ...
> >
> Any specification not written in a formal specification language (such as
> Z - http://www.comlab.ox.ac.uk/archive/z.html) will contain ambiguities;
> even the simplest (as demonstrated by Bertrand Meyer in "On Formalism
> in Specifications", IEEE Software, January 1985).
>
Of course.  libvorbis has no ambiguities (ignoring dependance on
underlying FP and libraries) yet it's not good as a spec because it's
hard to know that what it specifies is what Monty really had in mind
(although it must be very close by now, all big bugs have been fixed
already) and more importantly, it is not easy to read and to create
new implementations of it.  That's why formal specification languages
are not very popular, as far as I see - they are not convenient for
importing into a human's mind.

Yet some specifications, most notably RFCs, while written in informal
natural language, are very reable and leave remarkably little
ambiguity when read by a human being.  The Vorbis spec is not perfect
but quite good.  And the specific point I mentioned - that packets can
legally be truncated - is *very* explicitly and unambiguosly said in
it.  So I don't understand what's your precise point here.


-- 
Beni Cherniavsky <cben at tx.technion.ac.il>

If I don't hack on it, who will?  And if I don't GPL it, what am I?
And if it itches, why not now?  [With apologies to Hilel ;]
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