In the past, when faced with this question, I've usually gone on the principle
that if a function normally/ever gets called in list context, then it should
always return a "list", even in scalar context, i.e. if called in scalar
context return the last value in its return expression. This, imho, is the
minimally surprising behavior in most scenarios, and is also easiest to code as
you don't have to code for sensitivity to calling context. OTOH, obviously there
may be times when you'd rather have some other behavior; the only other one you
should "reasonably" implement is having it act like an array, i.e. return the
return list length when called in scalar context. But even that would warrant
documentation including several exclamation points. Any other behaviors
should, I think, be limited strictly to internal function calls, not in a public
interface.
A word spoken in Mind will reach its own level, in the objective world, by its own weight
