On 2018-07-25 23:53, David Mertz wrote:

On Wed, Jul 25, 2018, 11:27 PM Chris Angelico <rosuav@gmail.com> wrote:

means that you cannot do this:

>>> NullCoalesce(spam).nil is None

This IS fundamentally unfixable in a library.

Right now, you can still always call .unbox() at the end to get the underlying value. I agree that's a little ugly, hence why I added the wrapt proxy stuff. Most operations trigger unboxing, but indeed not simply echoing to the shell.

Chris is correct to point out this problem with comparing to None. I have that problem with my own version of the proxy library, similar to what David is building: I use the proxy heavily; to the point where almost any line may be touching a proxy rather than a real value. To avoid bugs, I disallow "is None" comparisons, mandating "== None" instead.

Using unbox() is an alternative, but it is uglier than than swapping "as" for "==".