>>1. No need to change PROCEDURE to FUNCTION. You can call either one as a function.
>
>Oh, I didn't really plan to change them; was just asking it theoritcally to prove the matter.

Unlike most, I do not use a procedure library at all. That means I never have to say SET PROCEDURE TO nor worry about which one is open. A .prg like this...

myudf.prg
LPARAMETERS tn1, tc2
*whatever
*optional return

can be called by DO myudf with params or MyUDF(params). Lots of typing savings excluding all those PROCEDURE and FUNCTION declarations ;)