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[ddlm-group] Feedback on draft CIF2 specification from JohnBollinger

Dear all,

If you haven't seen John Bollinger's useful feedback on our draft CIF2 specification, I recommend that you read it at


My response is as follows:

Points 1-8,10-13, 16, 19,23-26: editorial points with which I agree
Point 9: if the CIF2 header characters are missing, I suggest the file is treated as a CIF1 file.  This should be clarified in the spec.
Point 14: matching with the global, save, data etc. keywords should be case-insensitive.  This should be clarified in the spec
Point 15: (disallowing delimiters in strings).  Despite John's objections, I think this is a useful simplification which helps newcomers.  I believe that the PDB has deliberately started 'normalising' their files to remove embedded delimiters, which indicates to me that embedded delimiters are not a useful CIF1 feature.
Point 17,20: Yes, whitespace is allowed between opening/closing brackets and the first/last element.  Should be clarified
Point 18,22: semicolon delimited strings should be allowed as list and table elements.  Clarify in spec.
Point 21: while triple-quote delimited strings as table labels should be OK, allowing non-delimited strings as labels would require further restricting the character set of non-delimited strings to avoid e.g. <semicolon> appearing and confusing the parser (as we have discussed previously).  Using quotes just makes those sort of problems go away

Do others have any further comments?

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