On Thu, Jul 20, 2023, 01:19 Rob Cliffe via Python-ideas < python-ideas@python.org> wrote:
On 15/07/2023 21:08, Dom Grigonis wrote:
Just to add. I haven’t thought about evaluation. Thus, to prevent evaluation of unnecessary code, introduction of C-style expression is needed anyways:
1. result = bar is None ? default : bar
The below would have to evaluate all arguments, thus not achieving benefits of PEP505.
2. result = ifelse(bar is None, default, bar)
So I would vote for something similar to:
result = bar is None ? default : bar
Where default and bar is only evaluated if needed. Although not to the extent as initially intended, it would offer satisfiable solutions to several proposals.
Well, default is only evaluated if needed; bar is always evaluated. What is wrong with the Python equivalent
result = default if bar is None else bar or if you prefer result = bar if bar is not None else default
Note also that when the condition is a truthiness check -- admittedly not always the case, but it does occur reasonably often -- this can be simplified further to: result = bar or default