github-desktop VS jk

Yes that's a common problem with config languages. They're torn between competing priorities:

1. Fast to parse with a small engine, good error messages, safe to evaluate.

2. Powerful, can express config with arbitrary logic.

In Conveyor we try an alternative approach. The config is HOCON, which is a superset of JSON syntax designed for human readability/writability/convenience first and foremost, so it's got a very nice and clean feel to it. You can see an example here:

https://github.com/hydraulic-software/github-desktop/blob/co...

It can be parsed with a normal-sized config library and the errors you get are reasonable.

But then what if you hit the limits of what it can express? We added support for "hashbang includes":

    include "#!script.js"

People have tried: https://github.com/jkcfg/jk

But yeah I agree. The thing is, if all you need is robust determinism why do you need a full functional language with currying and other complex concepts?

Google had the same problem for Bazel, and their solution (Starlark) is way easier to understand.

If I were writing a build system today (and I did just write one actually to test out some ideas) I would use Typescript for the language with something like jk to provide hermeticity. Typescript has many advantages, especially over Python, but mainly:

It's possible to sandbox most languages, and with some work you can probably make them deterministic too.

Here's an example: https://github.com/jkcfg/jk

That beats having to learn an entirely new language.

Maybe Javascript? A lot of web tools support Javascript config files. There's this nice-looking effort to provide a hermetic execution environment for them: https://github.com/jkcfg/jk and if you use Typescript you get an extremely good static type system too. Plus the language is already very well known with loads of tool support and documentation.

Definitely what I would use today.

If you think "but I need conditionals and file inclusion and ..." then maybe consider just allowing a full programming language instead. Someone pointed me to jk which looks like it is heading in the right direction, except that it outputs YAML by default for some insane reason.

You may be interested in jk. If you don't want to use a special purpose configuration language (jsonnet, cue, dhall, etc), this is a nice alternative that uses js in a hermetic runtime (but see their open issues for progress on that). They seem to also be adding native typescript support so you could even have type checking built-in.