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> I've been lurking for a couple months, after discovering the work being done 
here, and just digesting the conversation. I wanted to briefly stick my head 
up and say hello and ask what if any discussion there's been about the ability 
to query ranges of dates in EDTF ? And specifically, how it is or would be 
implemented (at the brass tacks level).

I've implemented in my search engine date search by using a specialized 
indexing structure and algorithms acting upon the data.  The internal 
structures use integer prefix trees. In comparing dates my comparison, for 
example, determines the precision of the search term and the index object and 
compares on the basis of the least precise. The interesting observation is 
that from the perspective of search, a date with a specific precision can be 
like a date range given higher resolution. So dates and date-range index 
structure too are handled as two sides of the same coin.

I also use polymorphism so a date is both a date and date-range but also a 
sentence (a collection of words). During indexing date formats are recognized 
and parsed into an internal date structure representation and the structure 
and addresses of the words are stored as well in the fulltext index structure. 
Since dates often contain numbers (I parse also plain language dates so month 
names etc. are not uncommon) these numbers are also entered into the numerical 
data structure. This lets me interpret queries in a number of ways.







--

Edward C. Zimmermann, NONMONOTONIC LAB/BSn
http://www.ibu.de/IB_Engine
Umsatz-St-ID: DE130492967