David, your observation that Herbert and my responses "does little to address the point raised by Brian [T]"... as well as your explanation involving the phrase "it should be compliant and able to read CIFs using both DDL1 and DDL2 dictionaries." REALLY does highlight, in my view, the imprecision (verging on confusion) that can arise in these discussions. My last input was an attempt, admittedly a primitive one, to pin down what reading a CIF implies, and to distinguish the different concept levels that the STAR File support involves....so that when we talk about the CIF requirements we are not confusing them with the DDL requirements, and so on. So back to the beginning. Brian T said.... > from any file conformant to the CIF syntax." Someday I would like to > create some pdCIF read filters. I doubt that my code would tolerate DDL2 > files. Would I then be prohibited using CIF to describe these filter The meaning of Brian's comment "would tolerate DDL2 files." is what triggered my response. Was he referring to whether his CIF parser could read data files containing names that were exclusive to the DDL2 (mmCIF) dictionary? Or, was he implying that his CIF reader WOULD involve the pdCIF dictionary written in DDL1? That is, what are "DDL2 files", and what has this to do with reading a file conformant to the CIF syntax? My interpretation of the conformant conditions in the draft policy is that "reading a CIF data file" requires knowledge of the CIF syntax but absolutely none about reading a CIF dictionary. Of course one has to know WHICH data items (i.e. names) have to read, but whether they exist in a dictionary not material. That is why my "layered" table differentiated between a "CIF parser" and a "DDL parser"... the latter needs the former but not the reverse. OK, that is why David's comments are also confusing... and clearly if that misunderstanding exists among this select band, the policy state- ment has to be more precise and we need to get our terms straight! My hope is that this document be directed at the "CIF parser" level, because the requirements here are static and bound inexorably to the CIF syntax. Any level beyond that is more difficult and will change as the dictionaries and the DDL's evolve. Cheers, Syd. ------ firstname.lastname@example.org ,-_|\ Professor Sydney R. Hall / \ Director, Crystallography Centre Fx: 61(8)9380 1118 --> *_,-._/ Deputy Executive Dean of Science Ph: 61(8)9380 2725 v University of Western Australia www.crystal.uwa.edu.au Nedlands 6907, AUSTRALIA.
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