user defined functions

Hello,

As part of an ongoing project I am looking to migrate a large application from a proprietary OODBMS (that shall remain
nameless)to another database. Having read around a bit PostgreSQL looks like the best fit but I have a couple of
concernsabout the user defined functions which I wonder if anyone can address. 

(btw if this isn't the right forum for such questions I apologise and would ask some kind person to point me to the
rightlist) 

Firstly, am I correct in thinking that user-defined functions cannot be written in C++ or Java? (The FAQ gives C, SQL,
PL/pgSQL,Tcl, Perl, Python, or Ruby as the only possibilities) 
Secondly what sort of SQL interface to the user defined functions is available? For example if I defined a 'distance'
functionto compare two feature_vectors stored as BLOBs can I call  
    t1.feature_vector.distance(t2.feature_vector)
?

Thanks folks,

Alison

Alison Stevenson
IT Innovation Centre
2 Venture Road
Chilworth Science Park
Southampton SO16 7NP

Tel: +44 23 8076 0834
Fax: +44 23 8076 0833

mailto:as@it-innovation.soton.ac.uk
http://www.it-innovation.soton.ac.uk