How are the collections implemented?

[ShalokShalom]

I see that you provide different collections with immutability in mind.

Are they also implemented as immutable data structures?

If not, I recommend adding that info to the README section, that cares about the differences to FSharp.

In that case, I do suggest this as feature. :)

If it does, I recommend adding that info to the README as well.

[dbrattli]

@ShalokShalom the collections are implemented as immutable data-structures, but in Python nothing is really immutable except str, tuple, so for example the Block is an immutable list built on a tuple, and using the Block with the API provided will keep it immutable. But the class containing the tuple is not immutable, so you could always replace the tuple. We could try to make that harder to do, but it's not really the goals of this library to work around such issues with Python. But for classes like Block we could improve things and make the contained value e.g prefixed with underscore or double underscore.

[ShalokShalom]

Oh, I mean do they copy or reference? I mean, are they efficient, as immutable data structures in Clojure or FSharp? Or do they really copy stuff around, even though nothing is changed?

[dbrattli]

At least the Map implementation is the exact same code as F#. Block uses tuples which should be very efficient (since Python knows they are immutable and backed by c-code). I'm considering changing the Fable List impl. to use tuples when targeting Python. But it's hard to optimize lists. They just get better at one thing, and worse at another 😄

[ShalokShalom]

Exact same code? You mean you transpiled your/a F# map implementation to Python?

[dbrattli]

Yes, I could have done that now using Fable, but at the time I did it manually line by line. You can see that the Fable code (to the right) is not that different from Expression (on the left), but Fable still has a few more typing issues.

[ShalokShalom]

Oh wow, thats impressive on both sides 😄