I seem to be rambling. I will add, particularly to clarify my third paragraph (the big one): a library should not panic. It can have defensive panics, but overa

I seem to be rambling. I will add, particularly to clarify my third paragraph (the big one): a library should not panic. It can have defensive panics, but overall it should not panic, and triggering a defensive panic is to be treated as a bug. The exception is the panics that the application developer can reasonably be considered to have agreed to, and presumably the library should take care to make those panics as easy to handle as possible.