On Tue, Dec 3, 2019, at 13:43, Brett Cannon wrote:
> -1 from me. I can see someone not realizing an operator was changed,
> assuming it's standard semantics, and then having things break subtly.
> And debugging this wouldn't be fun either. To me this is monkeypatching
> without an explicit need for it, i.e. if you really want different
> semantics in your module then define a function and use that instead of
> influence-at-a-distance overriding of syntax.
Does it make a difference that it'd only apply to code that is physically in the same module where the function is defined? I'd originally planned to suggest full lexical scope for the lookup, in fact, so you could in theory do it within a single function.
Not enough to change my opinion. Changing how fundamental operators work just in a module is still influencing too far from the code site. For instance, if I navigate in my editor directly into the middle of a file or open a file and immediately start searching for the function I care about I won't notice that "+" no longer means what I thought it meant for integers because someone thought it would be smart to redefine that.
And as Serhiy pointed out, performance is going to get slammed by this, no opcode or not as you just introduced a new lookup on every syntactic operation.