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Re: Minutes - Action item (1) merging dictionaries

	This item seems to have fallen off with no resolution.  I have
been reviewing the discussion and, attractive as the notion of having the
CIFs specifying their own virtual dictionary is, I am not sure we should
rush into this.  At the very least we should gain some experience with the
use of this protocol at the level of merging official dictionaries before
allowing everyone to specify their own virtual dictionary.  As Brian
points out, the ability of a CIF to use a local dictionary to change the
definition of an item could well result in the file not being CIF
compliant.

	As far as the official dictionaries go, the msCIF dictionary can
include instructions to merge with coreCIF under any conditions it deems
necessary including changing the definitions, e.g., by increasing the
enumeration ranges.  Any CIF that declared itself comliant with the msCIF
dictionary would then be permitted anything that was allowed by the
virtual msCIF dictionary (including the extended enumeration range) and
would still be CIF compliant.  It would be up to Comcifs to ensure that
dictionaries made responsible use of the overlay feature.

	We still need to approve the merging dictionaries document, and my
vote remains for the original version.  I call on the other voting
members to approve the document, or indicate their reservations.

				David
			Chair, Comcifs


*****************************************************
Dr.I.David Brown,  Professor Emeritus
Brockhouse Institute for Materials Research, 
McMaster University, Hamilton, Ontario, Canada
Tel: 1-(905)-525-9140 ext 24710
Fax: 1-(905)-521-2773
idbrown@mcmaster.ca
*****************************************************



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