[MonetDB-users] User-defined MAL functions

Hi, I have some questions about using user-defined MAL functions I would like to create a function in MAL. 1) Is it possible that the function can take variable number of BATs as argument like in the case of algebra.joinPath(l:bat[:any,:any]... ) ? 2) If yes, how I can get the number of BATs passed as argument and 3) how I can get the n-th element of the argument? Thank you in advance Petros