dhall-lang VS cue

Fail to see how this is any different than Dhall (https://dhall-lang.org/) other than it produces plists too.

Kubernetes config is a decent example. I had ChatGPT generate a representative silly example -- the content doesn't matter so much as the structure:

https://gist.github.com/cstrahan/528b00cd5c3a22e3d8f057bb1a7...

Now consider 100s (if not 1000s) of such files.

I haven't given Pkl an in depth look yet, but I can say that the Industry Standard™ of "simple YAML" + string substitution (with delicate, error prone indentation -- since YAML is indentation sensitive) is easily beat by any of:

- https://jsonnet.org/

- https://nickel-lang.org/

- https://nixos.org/manual/nix/stable/language/index.html

- https://dhall-lang.org/

- (insert many more here, probably including Pkl)

There are underpowered languages / tools, that can only solve a problem for which they are intended poorly. But not all limited tools are like that.

Say, eBPF is prominently not Turing-complete, which allows to guarantee that a eBPF program terminates, and even how soon. Still eBPF is hugely useful in its area.

Or, say, regular expressions are limited to regular languages; in particular, they famously [1] cannot process recursive structures, like trees. Still tools like grep / ag / rg are mightily useful.

Yes, I agree that YAML is underpowered for proper k8s configuration! But it's also too powerful for its own good in other aspects [2]. I wish Google used Dhall [3] or their own purely functional config language (FCL? I already forgot the name) instead of YAML; sadly, they did not.

[1]: https://stackoverflow.com/a/1732454/223424

[2]: https://ruudvanasseldonk.com/2023/01/11/the-yaml-document-fr...

[3]: https://dhall-lang.org/

Dhall: Dhall is a programmable configuration language that combines features like JSON, functions, types, and import capabilities. Its style leans towards functional programming, so if you're familiar with functional-style languages such as Haskell, you might find Dhall to be quite intuitive.

I've been thinking along these lines but more 'strongly validated' than statically typed in the sense that you'd be better off being able to load the entire config and then produce a list of problems (and should be able to offer good editor support if done correctly).

Though https://dhall-lang.org/ demonstrates that you can statically type quite a lot of configuration to great advantage, which appears to be programmatically embeddable in multiple languages per https://docs.dhall-lang.org/howtos/How-to-integrate-Dhall.ht...

> Where practical is in the sense of an engineer (or in their terms, a CS practitioner),

Configuration processing. E.g. I'd like my yamls to be decidable, though I'd settle for guaranteed to halt[1].

[1] https://dhall-lang.org/

Maybe you'd like jsonnet: https://jsonnet.org/

I find it particularly useful for configurations that often have repeated boilerplate, like ansible playbooks or deploying a bunch of "similar-but" services to kubernetes (with https://tanka.dev).

Dhall is also quite interesting, with some tradeoffs: https://dhall-lang.org/

A few years ago I did a small comparison by re-implementing one of my simpler ansible playbooks: https://github.com/retzkek/ansible-dhall-jsonnet

And to checkout Dhall: https://dhall-lang.org/

I'm continuing to work on https://concise-encoding.org which is a new security-conscious ad-hoc encoding format to replace JSON/XML and friends. I've been at it for 3 years so far and am close to a release.

In a nutshell:

- Edit in text, transmit in binary. One can be seamlessly converted to the other, but binary is far more efficient for processing, storage and transmission, while text is better for humans to read and edit (which happens far less often than the other things).

- Secure by design: Everything is tightly specced and accounted for so that there aren't differences between implementations that can be exploited to compromise your system. https://github.com/kstenerud/concise-encoding/blob/master/ce...

- Real type support because coercing everything into strings sucks (and is another security risk and source of incompatibilities).

XML had a good run but was replaced by JSON which was a big improvement. JSON also had a good run but it's time for it to retire now that the landscape has changed even further: Security and efficiency are the desires of today, and JSON provides neither.

I've got the spec nailed down and can finally see the light at the end of the tunnel for the reference implementation in golang. I still need to come up with a system for schemas, but I'm hoping that https://cuelang.org will fit the bill.

Has anyone taken a look at Cue who can share any experiences?

https://cuelang.org/

It's mentioned on the site as an alternative to Yaml. Recently watched (~half of) this intro to it: https://youtu.be/fR_yApIf6jU

the most interesting summary explanation of cue lang and its differences is from a bug filing - https://github.com/cuelang/cue/issues/33

>CUE is a bit different from the languages used in linguistics and more tailored to the general configuration issue as we've seen it at Google. But under the hood it adheres strictly to the concepts and principles of these approaches and we have been careful not to make the same mistakes made in BCL (which then were copied in all its offshoots). It also means that CUE can benefit from 30 years of research on this topic. For instance, under the hood, CUE uses a first-order unification algorithm, allowing us to build template extractors based on anti-unification (see issue #7 and #15), something that is not very meaningful or even possible with languages like BCL and Jsonnet.

I agree with you. Personally, I think Cue is much better than either YAML, TOML or JSON because it adds the concept of types to the idea of describing configuration.

true, but the tooling and workflow remains the same.

Not sure of any tool that could abstract the details sufficiently to be widely adopted. There is just too much nuance in cloud config.

I'm exploring using CUE (https://cuelang.org) to define TF resources, exporting as JSON for TF. So far it's much nicer