Use pkl to validate existing config files

[derphilipp]

Is it possible to achive:

• Write a pkl template to validate types
• Write a Go(lang) program that reads an already existing json file and validate it with the help of the pkl template file

This way golang programs could harness the power of pkl without modifying the user expirience / config files of existing tools

[holzensp]

[aside: I'd prefer questions like this under Discussions]

Yes. You don't even need to write a Go program for the validation. That said, I think our editing experience is better than most JSON experiences. I guess "existing tools" might be a deal-breaker. Anyway, yes, you can always add the following to any template;

import "pkl:json"
import "package://pkg.pkl-lang.org/pkl-pantry/pkl.experimental.deepToTyped@1.0.2#/deepToTyped.pkl"

output {
  value = deepToTyped.apply(module.getClass(), new json.Parser {}.parse(read(read("prop:JsonPath"))))
}

Now, if you invoke Pkl with a value for external property JsonPath to point to your .json file, you can consume output.value as an instance of the module it's defined in.

[derphilipp]

Thank you very much and you are absolutely right, this should be under 'Discussion'!