Introduce new operator for syntactic sugar for is None and is not None

I quite often use None as a fallback/uninitialized value, e.g. for my:str? = None.

To test it, I have to write if my is None or if my is not None. I can use the ?? operator in some situations, but if an expression depends on the value being None or not, it doesn’t: result = a() if my is None else b(my)

What about introducing a is None operator? result = a() if ?= my else b(my) or if ?~ my: result = b(my); else result = a()

That would be an unary operator similar to not, but checking for the object being None or not.

[ymeine]

@evhub I am not the requester of the feature. But that’s true I do think it makes sense to have the unary equivalent of the binary operator ??. The mention of the “or-like feature” in LiveScript was just to explain how the operator works there, highlighting that it’s using the same special characters for both unary and binary versions. I’m aware the binary version already works in Coconut, and that’s actually the unary equivalent which is being requested.

Therefore yes, the two benefits are only:

• consistency with the existing None aware operators, to have a comprehensive set
• a bit more conciseness: obj is None becomes obj??

Of course this is already doable is a non-ambiguous and non-cumbersome way, compared to what the binary version solved (a if a is not None else b becomes a ?? b which is far more valuable, especially when starting to add more operands in the expression)

[evhub]

What’s wrong with obj is None? It’s short, descriptive, and gets the job done. This feels to me like the one None-aware operator use case where Python really already has this down.