On Sat, Sep 10, 2016 at 4:27 PM, Chris Angelico <rosuav@gmail.com> wrote:
On Sun, Sep 11, 2016 at 9:10 AM, Guido van Rossum <guido@python.org> wrote:
So you're offering `NoneCoalesce(x).bar` as less-ugly alternative to `x?.bar`... Color me unconvinced.
As a syntactic form? Not interested. But what if it's the underlying implementation? We have "yield from X" as a tidy syntax for roughly a page of equivalent code. We could have "x?.bar" as syntactic sugar for "NoneCoalesce(x).bar".
PEP 505 has an option for a way to customize the coalescing operation (https://www.python.org/dev/peps/pep-0505/#generalized-coalescing). Though I think I'd rather not do that. But it just occurs to me that the implementation given by David Mertz is not what I'd expect: it seems that `NoneCoalesce([]).flup` would catch the AttributeError (there' no `[].flup`) and return NoneCoalesce(None), whereas I would expect `?.` to only return None when the LHS is None, not when some other not-None object doesn't have the requested attribute. (And the "pile of poo" operator in PEP 505 agrees with me.) -- --Guido van Rossum (python.org/~guido)