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Re: COMCIFS adoption of DDL1

I certainly favor adoption of DDL1 some DWG (or DDLWG?), with COMCIFS as
the default backup.  In addition, it would be a good idea to announce the
current membership of the DDL2 and star_DDL DWGs (or DDLWGs) as well
as the various dictionary DWGs with links to any reference definitions,
group home pages and discussion lists organized into a table.  That way
all the essential reference information on who handles what and what
it is they are handling can all be traced from one central location
managed by COMCIFS.   It might be a good idea to confirm with each
of the putative chairs and members of  each of the DWGs/DDLWGs that
they know that they are involved and that they are still willing and
able to be involved. If we discover any other orphans in the process of
making the table, I would suggest we adopt them as well until we can
find them a nice new home or they are put to a peaceful rest.


At 3:14 PM -0400 10/14/05, David Brown wrote:
>The CIF dictionaries are written using a Dictionary Definition 
>Language (DDL) which is described in a DDL dictionary.  Both the 
>DDL- and CIF-dictionaries use the same DDL and syntax so that is 
>should be possible to read any of the dictionaries using the same 
>Currently there are two versions of DDL in use.  DDL1 is used for 
>the coreCIF and related dictionaries while DDL2 is used for the 
>mmCIF and related dictionaries.  When these various dictionaries 
>were originally designed it was anticipated that a program designed 
>to validate a CIF could also be used to validate CIF- and 
>DDL-dictionaries.  However, since most of the programming effort has 
>been directed towards the manipulation of CIFs, it is only quite 
>recently that anyone has taken up the challenge of writing software 
>to validate CIF- and DDL-dictionaries against the appropriate 
>version of DDL.  In the course of this work it became apparent that 
>DDL1 contains some errors that make such validation impossible.  The 
>errors are easy to corrected, but there is no individual or 
>organization that has the responsibility for managing DDL1 or the 
>authority to approve any changes.  DDL1 is an orphan even though it 
>underpins the whole CIF project.
>DDL1 was written by Hall and Cook (J. Chem. Info. Comp. Sci. (1995) 
>35, 819-825), but they have moved on and are not interested in 
>managing the earlier versions of DDL.  At the COMCIFS closed meeting 
>in Florence there was general agreement that, because an 
>authoritative definition of DDL1 is essential to the functioning of 
>many of the CIF dictionaries, COMCIFS should take responsibility for 
>its maintenance.  That decision will need to be formally ratified by 
>the voting members of COMCIFS, but before I ask for that vote, I am 
>circulating the proposal to members of the COMCIFS Discussion List 
>for their comment.
>The Florence meeting of COMCIFS also endorsed the idea of moving 
>towards a new (third) version of DDL (star_DDL) that would be 
>compatible with CIF archives written in either DDL1 or DDL2, but 
>that would in addition benefit from what we have learned over the 
>past fifteen years and consequently would result in a much more 
>powerful version of CIF.
>One might ask why it is necessary to patch up DDL1 if it is likely 
>to be superceded by star_DDL.  There are a couple of reasons. 
>Firstly, there is much work to be done before star_DDL is ready for 
>general use, and dictionaries written using earlier  DDLs will 
>likely continue in use for many years in parallel with star_DDL. 
>Secondly, the experience gained by developing advanced software for 
>DDL1 will be useful in developing software for star_DDL.
>If you have any comments on this proposal, can you please post them 
>on the COMCIFS Discussion List by Replying to this message during 
>the next four weeks.  After that time I will ask the voting members 
>of COMCIFS to formally adopt the proposal that COMCIFS take 
>responsibility for the management of DDL1.
>David Brown
>Chair of COMCIFS
>Attachment converted: Macintosh HD:idbrown 38.vcf (TEXT/ttxt) (001CB6A0)
>comcifs mailing list

  Herbert J. Bernstein, Professor of Computer Science
    Dowling College, Kramer Science Center, KSC 121
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