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Re: [ddlm-group] New syntax: 'marker' characters

Hi Herbert and colleagues: Herbert has proposed a finer-grained
solution to part of the original problem. One part of the problem I
was addressing was that very large CIF files are not necessarily laid
out in a manner that allows for efficient selective processing.
Herbert's proposal doesn't completely solve this problem, in that one
still needs to parse all preceding parts of the file in order to get
to a particular section.  Herbert's solution does give a performance
boost to those programs that need something from the earlier part of a
datablock, in those cases where someone has adopted the recommended
ordering.

Quite apart from the markers proposal, I think it would be worth
exploring Herbert's proposal further, although I don't understand the
reasons one would need such a fine-grained ordering.

On Fri, Oct 30, 2009 at 4:29 AM, Herbert J. Bernstein
<yaya@bernstein-plus-sons.com> wrote:
> The idea of markers creates interesting possibilities and problems with
> respect to ordering.  Isn't the real issue one of relative ordering of
> presentation of categories, rather than beginning, middle and end?
> We could just as easily have a need to organize the middle in more detail.
> The same issues may also arise within a category.

> How about adding an arbitrary string as an attribute for any item or
> category giving its suggested sort order, where the sorting would be
> done lexicographically among the strings, with no specified ordering
> among items with the same value.  Note that a blank string comes before
> all other strings.
>
> If nothing were specified the intention would be to assume the ordering
> string ".", so that strings beginnng with blank would sort ahead of
> all items with no specified ordering and strings beginning with any
> letter of the alphabet would sort after the unspecified orderings.
> This would give the effect of beginning, middle and end, but allow
> arbitrary insertions into the order.
>
> Thus  " beginning" would come before the unspecified orderings and
> "zzz_end" would come after all of the unspecified orderings.
>
> There may be other presentation issue, so I would suggest starting
> a PRESENTATION category with the tag
>
>   _presentation.suggested_ordering
>
> the value of which would be a Text (if we want to allow the maximal
> flexibility) or Code (for simplicity).
>
> Note that this would be a suggested ordering, not mandatory.

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