debug-trace-var VS proposal-operator-overloading

> Can you give me an example of a Haskell expression which isn't reverentially transparent (without unsafePerformIO)?

Yes: https://github.com/ncaq/debug-trace-var The trick, however, is not unsafePerformIO (destructive mutability has nothing to do with referential transparency in general) but with TemplateHaskell, as quoting has everything to do with referential transparency.

> But the bog standard FP definition is a real and useful concept.

Actually, it's rather tautological. It defines FP circularly (see my comment here: https://news.ycombinator.com/item?id=36152488). It says nothing more than the far more useful explanation: "the meaning of every expression is a value".

There's a not-very-active proposal to add operator overloading to JS which takes a similar scoped approach:

https://github.com/tc39/proposal-operator-overloading

There's a proposal to add operator overloading to the language, but AFAIK it never landed.

An example of it would be the operator overloading proposal https://github.com/tc39/proposal-operator-overloading that would allow overriding === and it would also solve in one shot many other problems (like numeric types extension, pipeable operator, and all the ones listed in the proposal).

Kind of but not really. There is the concept of operator overloading that would let you specify how to handler uses of operators like - and + with your class instances, but this is not yet officially supported in JavaScript. There is an operator overloading proposal to maybe add it in the future (and if you're using QuickJS that has support built in), but right now there's not a whole lot you can do.

Though this is not possible now since operators always work on primitive values, there is a proposal for operator overloading that could potentially allow us to use operators on objects in the future. It's still very early, so its not something you can use today (or anytime soon, if ever at all). In the meantime, you'll need to use method calls to perform these kinds of operations.

I'm not sure who hates it, but I have seen it abused (which people don't like). But, quickjs has it now, and there's a proposal to have it added to the JS spec. The proposal is only stage 1, so who knows what will happen with it or when, but its not counted out.

https://github.com/tc39/proposal-operator-overloading

There are still a couple issues that have to be solved. m2c: I hope that won't get to stage 3, though I like operator overloading in general, I think it's something that will complicate JS even more.