moon VS starlark

(for context - I'm not interested in first class node support)

This seems pretty cool. I particularly like how 'gradual' it seems to be relative to things like Bazel, i.e. you can take some shell scripts and migrate things over. I did have a play and hit an initial problem around project caching I think, which I raised at [0].

One comment, from the paranoid point of view of someone who has built distributed caching build systems before is that your caching is very pessimistic! I understand why you hash outputs by default (as well as inputs), but I think that will massively reduce hit rate a lot of the time when it may not be necessary? I raised [1].

As an aside, I do wish build systems moved beyond the 'file-based' approach to inputs/outputs to something more abstract/extensible. For example, when creating docker images I'd prefer to define an extension that informs the build system of the docker image hash, rather than create marker files on disk (the same is true of initiating rebuilds on environment variable change, which I see moon has some limited support for). It just feels like language agnostic build systems saw the file-based nature of Make and said 'good enough for us' (honorable mention to Shake, which is an exception [2]).

[0] https://github.com/moonrepo/moon/issues/637

There are many tools like Lerna, Nx, Turborepo, Moon, Rush, and Bazel, to name a few. Today, we'll be using Turborepo, as it's lightweight, flexible, and easy to use.

You should give moon a try: https://moonrepo.dev/

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