DDL1-DDL2

[James Hester <jrh@xxxxxxxxxxxx>]

On Thu, 2005-07-14 at 16:26 +0100, Matthew Towler wrote:
> The sentence following your question and the quote below make my 
> comments rather redundant.  As long as a hypothetical DDL 1.5 did not 
> make the vast majority of existing DDL 1.4 CIFs invalid then there is 
> not a problem and programs could be updated as you suggest. I had 
> misunderstood that 1.4 and 1.5 would be incompatible in some way.

Yes, I think John expressed the situation very clearly, and I think of
the changes that have been suggested as janitorial work rather than
trying to enhance DDL1.  

You mentioned the relationship between DDL1 and DDL2.  Standing where I
am (largely unaware of the technical considerations that went into the
DDL2 design decisions) it appears that the DDL2 authors did 2 things;
they "cleaned up" DDL1, and they enhanced it (In the latter category I'm
thinking particularly of the way parent-child relationships are
expressed in DDL2, and the use of implicit attributes).  If DDL1 were to
adopt some of the DDL2 cleanups it would still (fortunately or
unfortunately) be a long way from being DDL2, but be a more robust
standard.

James. 
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