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Re: [ddlm-group] A modest addition to the DDLm spec. .. .. .

On Thursday, September 30, 2010 4:05 PM, Herbert J. Bernstein wrote:

>Try working with some of the longer regexes for a while and you may
>come to appreciate having something like the plus or the line-folding
>backslash to allow you to present what really in one very long
>single-line character string with lots of funny stuff in it
>over a series of line and broken with some whitespace that is
>not part of the string.

You do not need to persuade me of the usefulness of breaking up regexes.  I fully appreciate it.  I remain unclear on these points, however:

1) Are dictionary regexes and adjusting to the quoting rule changes the principal use cases driving this proposal?

2) Why is the use of text fields with the existing line-folding protocol not a sufficient solution?

3) For regexes, why is it better to add a new feature to CIF than to modify the DDL's regex data type to accommodate insignificant whitespace?  That would give you an even clearer way to break up regexes, and the scope of the change would be much more contained.

>However, the question is not one of your taste or mine or Nic's, nor
>even whether the feature is useful to everybody, but whether
>it is useful to some reasonable number of people and
>whether having it causes some kind of problem for other people.

That is one important question, but by no means the only relevant one.  I could suggest two or three changes that would be useful to some people and harmless to everyone else, but that is not (history shows) sufficient justification to adopt them.

In any event, I think the proposed change does cause problems: it will confuse some people, it will incrementally complicate the production, testing, and maintenance of CIF software, and it may render invalid some existing CIFs that otherwise would be valid CIF2.  How serious those problems are, and whether they would be offset by the benefits that would be realized is unclear to me.  Whether substantially the same benefits could be realized in a manner that carries fewer problems is also unclear to me.

What happened to the urgency to finish CIF2?  Surely opening a discussion on a new change proposal is not conducive to swift completion of the work.

What happened to the principle of avoiding changes whose implications and impact are not fully understood?  I submit that this proposal describes such a change.

I apologize, but I think the best course of action is to table this proposal, for reconsideration when the next revision of the CIF specification is designed.


John C. Bollinger, Ph.D.
Department of Structural Biology
St. Jude Children's Research Hospital

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