RE : How do I compile/test a PL/SQL in Postgresql

Hi,

I am a novice to PostgreSQL (although I know ORACLE's PL/SQL very well)

I have written a Stored Function in PostgreSQL but cannot figure out how
to compile it or run it in PostgreSQL. In ORACLE, one would have to

do this at SQL*PLUS prompt : @<file-path\file_name to compile the stored
function into ORACLE DB.

In PostgreSQL, how do I do that?

In ORACLE, one would have to write a PL/SQL to test the stored function
(and use DBMS_OUTPUT.PUT_LINE) to get the stored function to write to
stdout.

In PostgreSQL, how do I test the stored function? I noticed none of the
documentation or books seemed to mention this simple point.

Best regards