[Python-ideas] PEP 505 (None coalescing operators) thoughts

Sven R. Kunze srkunze at mail.de
Mon Sep 28 18:11:45 CEST 2015

On 28.09.2015 18:02, Jeff Hardy wrote:
> TL;DR:
> +1 for the idea
> -1 on the propagating member-access or index operators
> +1 on spelling it "or?"
> C# has had null-coalescing since about 2005, and it's one feature I 
> miss in every other language that I use. I view null/None as a 
> necessary evil, so getting rid of them as soon possible is a good 
> thing in my book. Nearly every bit of Python I've ever written would 
> have benefitted from it, if just to get rid of the "x if x is not None 
> else []" mess.
> That said, I think the other (propagating) operators are a mistake, 
> and I think they were a mistake in C# as well. I'm not I've ever had a 
> situation where I wished they existed, in any language. Better to get 
> rid of the Nones as soon as possible than bring them along. It's worth 
> reading the C# design team's notes and subsequent discussion on the 
> associativity of "?." [1] since it goes around and around with no 
> really good answer and no particularly intuitive behaviour.
> Rather than worry about that, I'd prefer to see just the basic 
> None-coalescing added. I like Alessio's suggestion of "or?" (which 
> seems like it should be read in a calm but threatening tone, a la Liam 
> Neeson). It just seems more Pythonic; ?? is fine in C# but seems 
> punctuation-heavy for Python. It does mean the ?= and ?. and ?[] are 
> probably out, and I'm OK with that.
> - Jeff
> [1] https://roslyn.codeplex.com/discussions/543895

That sums it all up for me as well, though I would rather use "else" 
instead of "or?" (see punctuation-heavy).


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