traitlets VS starlark

Try traitlets

https://github.com/ipython/traitlets/pull/693 should help.

> This is loosely the same idea that drives React, ObservableHQ, Kafka, and other event-streaming architectures, but I first encountered this ~15 years ago at a bank.

See also the "observer pattern" [0]. It's a fun exercise to implement a reactive system in Python using the descriptor protocol [1]. IPython's traitlets library is an example of this in the wild [2].

[0]: https://en.wikipedia.org/wiki/Observer_pattern

[1]: https://docs.python.org/3/howto/descriptor.html

[2]: https://github.com/ipython/traitlets

The implementations and users page mentioned above:

https://github.com/bazelbuild/starlark/blob/master/users.md

Starlark: Starlark is a language for describing build transformations, inspired by Python, but with features that make it suitable for embedding in software like Bazel. It can be used for configuration generation due to its capability for deterministic evaluation and expressing complex build transformations.

In the design of Starlark (https://github.com/bazelbuild/starlark), I often had to push back against new feature requests to keep the language simple. I explicitly listed simplicity as a design goal.i

Of course, the scope of the language is not the same as general purpose languages, but there's always pressure from the users to add more things. I also think many people underestimate the cost of adding new features: it's not just about adding the code in every compiler/interpreter, specifying every edge-case in a spec, updating all the tooling for the language and writing tutorials; it's also a cost on everyone who will have to read any of the code.

one of the benefits of starlark (unlike python): "Starlark is suitable for use in highly parallel applications. An application may invoke the Starlark interpreter concurrently from many threads, without the possibility of a data race, because shared data structures become immutable due to freezing." from https://github.com/bazelbuild/starlark/blob/master/spec.md - it's not python, you can't do recursion (!) and it's more limited (you can't read a file in bazel, and parse it, you have to make this operation into the graph somehow)

You can do the same in Bazel which uses Starlark for its BUILD files. Starlark is a dialect of Python so it makes it super easy to work with.

Make sense. We do not use Python actually, the build language is starlark, which is the config lang used by bazel. https://github.com/bazelbuild/starlark

Have you seen Starlark? It's not too far from that, but safer in a number of ways: https://github.com/bazelbuild/starlark