Converters with a custom ValueRenderer

[joshqou]

I want to abstract a configuration format that is not officially supported, however ValueRenderer doesn't seem to support the converters mapping.

class Space {
    box: Box
}

class Box {
    id: String
    color: Color
    label: String?
}

space: Space

[Space]
BoxID=box_1
BoxColor=red
BoxLabel=A readable label

Is there a way of doing this using pkl instead of outsourcing the conversion and rendering to jq?

[bioball]

I'm curious what jq has to do with this; do you ultimately need JSON?

What format is this? Is this some flavor of INI?

Generally, you want to use a renderer to define how Pkl gets serialized to text. You can write an in-language renderer (see our toml renderer for an example). @Madmegsox1 also submitted a PR to add an INI renderer to the stdlib in #149, which might help you.

[joshqou]

I'm curious what jq has to do with this; do you ultimately need JSON?

I've been using jq to do the actual rendering by having pkl render to JSON. I hadn't read the output section in the language ref initially so it made more sense to me

$ set -eu -o pipefail
$ pkl eval -f json file.pkl | jq -rf file.jq # > file.conf 

{
    Space: (if .space != null then .space | {
        BoxId: .box?.id,
        BoxColor: .box?.color,
        BoxLabel: .box?.label
    } else null end)
} | to_conf

What format is this? Is this some flavor of INI?

It's a flavor of INI with multiple key assignment support, similar to systemd.unit.

Generally, you want to use a renderer to define how Pkl gets serialized to text. You can write an in-language renderer (see our toml renderer for an example). @​Madmegsox1 also submitted a PR to add an INI renderer to the stdlib in #149, which might help you.

I did try writing the renderer in pkl however got caught out when I realised converters wasn't implemented by ValueRenderer since I wasn't sure how to implement converters myself within pkl. I don't think the PR renderer would work for the specific INI flavor I'm targetting as it's using Map

The OP may have been a bit vague so here's a more clear description of what I'm wanting to achieve within pkl:

• Target a custom INI flavor where a key may be assigned multiple times. I'm currently handling this inside my to_conf jq function
• Wanting to unflatten the schema. i.e: box { id = "str" } instead of BoxId = "str" for readability

[holzensp]

A general implementation of converters also needs the ability to "resume" conversion; at the moment, a path converter (one where the key is "foo.bar.baz" instead of Foo.getClass()) can not be defined recursively, because the definition doesn't have access to the path itself.

That said, for this application, just defining your own output should be fine.