On 28.09.2015 23:49, Guido van Rossum wrote:
On Mon, Sep 28, 2015 at 2:06 PM, Donald Stufft <donald@stufft.io> wrote:
I’m not a big fan of the punctuation though. It took me a minute to realize that post?.tag.lower() was saying if post is None, not if post.tag is None and I feel like it’s easy to miss the ?, especially when combined with other punctuation.
But that's a different point (for the record I'm not a big fan of the ? either).
Me neither. The proposal simply doesn't have the right balance between usefulness and complexity added to the language (esp. for new Python programmers to learn in order to be able to read a Python program). In practice, you can very often write "x or y" instead of having to use "x if x is None else y", simply because you're not only interested in catching the x is None case, but also want to override an empty string or sequence value with a default. If you really need to specifically check for None, "x if x is None else y" is way more expressive than "x ?? y". For default parameters with mutable types as values, I usually write: def func(x=None): if x is None: x = [] ... IMO, that's better than any of the above, but perhaps that's just because I don't believe in the "write everything in a single line" pattern as something we should strive for in Python. The other variants (member and index access) look like typos to me ;-) -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Experts (#1, Sep 29 2015)
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