new contrib/tree, 65535 children !

Hi,

we're about to release new version of contrib/tree available from
http://www.sai.msu.su/~megera/postgres/gist/tree/tree.tar.gz
Brave could test it, very sparse doc is in README.tree (in russian).

The basic idea is to represent node by path from root,
so '3.4' means 4-th child of 3-rd child of the root.

We introduce two types for handling trees:

entree (enumerated tree) and bitree (bit tree).

bitree is actually what we already used in previous version
and has limitation on number of children, specified in compilation -
8,16,32(on default),64.

This limitation and discussion in mailing list (Hanny, Don) inspired us to
implement another type - 'entree', which has maximum number of
children - 65535 !!! Thanks Eugeny Rodichev for fruitful discussion.

We have tested the module with 7.2 release.

Regards,    Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83