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 concerns about 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 right list)

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' function to 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
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Southampton SO16 7NP

Tel: +44 23 8076 0834
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mailto:as(at)it-innovation(dot)soton(dot)ac(dot)uk
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