Honestly speaking, I don't want make Python syntax more complex. But when comparing to accepted PEP 572, I think this PEP is useful often enough. And PEP 505 doesn't break border between expression and statement unlike PEP 572. Especially, ?? and ??= seems useful very often. And `x ?? default` seems much more readable than `x if x is not None else default` or `default if x is None else x`. On the other hand, `?.` and `?[]` seems useful less often and more confusing. When looking `spam?.egg`, people can expect `getattr(spam, 'egg', None)` rather than `spam.egg if spam is not None else None`. Since `?.` and `?[]` can't avoid AttributeError, IndexError and KeyError, I think it's confusing and not useful enough compared with it's ugliness. So my current position is +1 for `??` and `??=`, but -1 for others. Regards, -- INADA Naoki <songofacandy@gmail.com>