COMCIFS adoption of DDL1
David Brown idbrown at mcmaster.caFri Oct 14 16:14:12 BST 2005
- Previous message: Proposed COMCIFS terms of reference
- Next message: COMCIFS adoption of DDL1
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
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 software.. 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 One might ask why it is necessary to patch up DDL1 if it is likely to be superceded by star_DDL.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 -------------- next part -------------- A non-text attachment was scrubbed... Name: idbrown.vcf Type: text/x-vcard Size: 298 bytes Desc: not available Url : http://scripts.iucr.org/pipermail/comcifs/attachments/20051014/c82cac73/idbrown.vcf
- Previous message: Proposed COMCIFS terms of reference
- Next message: COMCIFS adoption of DDL1
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
More information about the comcifs mailing list