Re: using Tsearch2 for chemical text

Naz, in posted link to the dict_regex dictionary for tsearch2 
http://lynx.sao.ru/~karpov/software/postgres_dict_regex.html

Feel free to test it and send us feedback. It's rather general, of course,
it uses regex (pcre library).

Oleg
On Thu, 26 Jul 2007, Naz Gassiep wrote:

>
>> I think you might need to write a custom lexer to divide the strings
>> into meaningful units.  If there are subsections of these names that
>> make sense to search for, then tsearch2 can certainly handle the
>> mechanics of that, but I doubt that the standard rules will divide
>> these names into lexemes usefully.
>
> A custom lexer for tsearch2 that recognized chemistry related lexical 
> components (di-, tetra-, acetyl-, ethan-, -oic, -ane, -ene etc) would 
> increase *hugely* the out-of-the-box applicability of PostgreSQL to 
> scientific applications. Perhaps such an effort could be co ordinated with a 
> physics based lexer and biology related lexer, to perhaps provide a unified 
> lexer that provided full scientific capabilities in the way that PostGIS 
> provides unified geospatial capabilities.
>
> I don't know how best to bring such an effort about, but I do know that if 
> such a thing were created it would be a boon for PostgreSQL, giving it a very 
> significant leg up in terms of functionality, not to mention the great 
> positive impact that the wide, free availability of such a tool would have on 
> the scientific research community.
>
>
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 	Regards,
 		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(495)939-16-83, +007(495)939-23-83