- operator overriding
- look up interception API
- metaclasses
- embdedded design patterns: iterator, singleton, context manager, etc.
- multiple inheritance
- standardised imports, with hooks
- controlled gc
- dict comprehension
- generator expressions
- type hints
- string formatting language and operations
- much more comfortable lists
- rich built ins (all, any, enumerate, zip...)
- no weird implicit type casting and comparison rules
- stack traces and very explicit error messages
- support of a lot of charsets out of the box
- multiple notations for text and numbers
- types for bytes
- support for imaginary numbers
And so much more.
Because Python is such an easy language to use, it's easy to think it's just a simple scripting language.
It's not.
It is very, very powerful.
But it has such a smooth learning curve and you can be productive in it so quickly a lot of people never need to see it.
You can compare Ruby to Python. Or Go.
But JS ? It's not even on the same planet. The only reason this abomination has this success is because it has an accidental monopoly on the most awesome and popular platform of the human race: the web.
One of the best things about JS is that is has none of these features. Smaller languages are better, and blindly adding features is not the way to improve a language.
Unfortunately, nothing in JS can ever really go away, so it's starting to leave the "small language" sweet spot.
JS is better than Ruby by being smaller and infinitely better specified. Go is a nicer language due to being designed from scratch recently by people with excellent taste.
When I say transpiler, I don't mean just mapping one syntax to another. I mean either really compiling to JS, or having a python bytecode interpreter in JS. It is possible to compile very different languages to JS, for example Nim.
I think it should be possible to support 100% of the core language - even metaclasses, why should that feature be more difficult? Of course you would not map Python classes to JS classes! You would map Python classes to something else, like opaque JS objects.
It is not realistic to support 100% of the library, but that is not neccessary - on the frontend, you wouldn't need to use most libraries, and you don't need C FFI. Most of the time, you'll be only pushing JSON or python objects into templates.
