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Re: [ddlm-group] Draft EBNF for CIF2

We will have a lot less trouble with the new dictionaries if we don't 
use nested save frames in them.
We don't need nested save frames in a dictionary. We don't need any save 
frames, nest, or otherwise
in a data file. Let's save nesting of save frames until we have an 
actual use case.

That being said, I am a great fan of liberal parsers than can make sense 
of natural extensions of the
language they should formally read.

On 8/27/14 10:40 AM, Bollinger, John C wrote:
> I'm having trouble seeing the down side of providing for save frame nesting in the CIF2 syntax specifications.  Doing so would enable *but not require* nested frames to be used in DDLm and DDLm dictionaries, but any way around they are irrelevant to DDL1 and DDL2 dictionaries (whether written in CIF1 or CIF2 syntax) and to all CIF data files currently envisioned.  To a parser that does not understand them, nested frames will look like a combination of a missing frame terminator between adjacent frames plus an extraneous frame terminator at some later point, and such a parser must be prepared to handle those errors in some way anyway (that is exactly the CIF1 situation).  A parser specialized for a domain to which nested save frames are not relevant can be such a parser, since nested frames would be erroneous in its target domain anyway.
> On the other hand, allowing nested frames in the syntax would maximize our leverage from the Perth group's existing tools and recent work.
> Regards,
> John

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