I use a set of DDL scripts to automatically create the database for an app.
I need to create certain functions (from contrib), if they're not there already. If they are there, I don't want to DROP or REPLACE them, since they may be used in certain indexes and triggers.
Is there a way to only CREATE a function if it is not defined already? Is there a simple way to see if the function is defined?
(I don't want to just try creating it and letting it fail, since the DDL runs in a transaction).
