Dave Rolsky wrote: >I'd prefer multiple methods to a third parameter. Different names provides >clarity. Who would know what a number means without looking in the docs?
It's not meant to be used without reading the doc at least once.
Once read, of course, the $which values follow a logical plan and so
are memorable.
If you want three names, how about
prev_observance_start_for_datetime
this_observance_start_for_datetime
next_observance_start_for_datetime
-zefram
