dhall-aws-cloudformation VS skycfg

I have been writing a fair amount of Dhall using autogenerated CloudFormation bindings ( https://github.com/jcouyang/dhall-aws-cloudformation/ ). It is a fantastic way to reduce boilerplate and factor out recurring blobs. My main frustration is that the type checker is not smart enough (or maybe the type system is undecidable?) - every time you want to use a polymorphic function, you must pass in the type parameters yourself (this is also true for empty lists and `None`). This makes simple FP idioms extremely noisy, to the point where you're better off writing longhand. In a language that's meant to be alleviating YAML/JSON boilerplate.

It's still a massive improvement, but it could be so much better if the typechecker was smarter.

I can definitely sympathize here - in every context, just straight JSON/YAML configuration seems never expressive enough, but the tooling created in response always seems to come with sharp edges.

Here are some of the things I appreciate about Jsonnet:

- It evals to JSON, so even though the semantics of the language are confusing, it is reasonably easy to eval and iterate on some Jsonnet until it emits what one is expecting - and after that, it's easy to create some validation tests so that regressions don't occur.

- It takes advantage of the fact that JSON is a lowest-common-denominator for many data serialization formats. YAML is technically a superset of JSON, so valid JSON is also valid YAML. Proto3 messages have a canonical JSON representation, so JSON can also adhere to protobuf schemas. This covers most "serialized data structure" use-cases I typically encounter (TOML and HCL are outliers, but many tools that accept those also accept equivalent JSON). This means that with a little bit of build-tool duct-taping, Jsonnet can be used to generate configurations for a wide variety of tooling.

- Jsonnet is itself a superset of JSON - so those more willing to write verbose JSON than learn Jsonnet can still write JSON that someone else can import/use elsewhere. Using Jsonnet does not preclude falling back to JSON.

- The tooling works well - installing the Jsonnet VSCode plugin brings in a code formatter that does an excellent job, and rules_jsonnet[0] provides good bazel integration, if that's your thing.

I'm excited about Jsonnet because now as long as other tool authors decide to consume JSON, I can more easily abstract away their verbosity without writing a purpose-built tool (looking at you, Kubernetes) without resorting to text templating (ahem Helm). Jsonnet might just be my "one JSON-generation language to rule them all"!

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Though if Starlark is your thing, do checkout out skycfg[1]

[0] - https://github.com/bazelbuild/rules_jsonnet

[1] - https://github.com/stripe/skycfg

Can you say more about what GCL does better than all of the open source ones?

Anecdotally, I've heard a lot of GCL horror stories, and many Xooglers have chosen to create things like Jsonnet or Skycfg (https://github.com/stripe/skycfg) instead.

If you’re looking at other solutions check out https://github.com/stripe/skycfg It works with Envoy and lots of other things that support protobuf configs

This is good and there are several other options like https://github.com/stripe/skycfg#why-use-skycfg to add full language support (using Go or python for ex) to configurations.