Define a cast function from day_interval to int

Hi,

I am currently migrating monetdb from an old version to the current release, and I noticed that the difference of 2 dates return a day_interval and cannot be cast to an int and I have to use the "day" function for this purpose.

This is fine for newly written scripts, but for old scripts I am hoping to avoid a rewrite.

ex: cast(date1-date2 as int) return an error: types day_interval(4,0) and int(32,0) are not equal

How to define a cast function from day_interval to int to avoid any changes to the old scripts?