Add Serde support

[zkat]

This PR adds full serde support to kdl-rs. It works kinda like quick-xml

[TheLostLambda]

Hi @zkat !

I have a bit of time in the evenings in the coming week and was thinking I could take a swing at this! I've been using knuffel / knus stuff again, but since you planted the quick-xml stuff in my head I've wanted to help make that happen and kinda replace knus.

Let me know if I should hold off / if you've been working on this offline — I don't want to step on your toes!

[zkat]

@TheLostLambda oh god yes please help. Save me. I hate this so much 😂

[TheLostLambda]

Haha, oh dear... I'll try my best... Watching the Jon Gjengset video now and I'll keep you posted on any progress! 😅

[TheLostLambda]

Hi @zkat ! I've been looking into this a bit and whilst I'm sure it is possible, the more looking I've done the more I'm on the fence about if it's the right way to go about this?

I'm very open to being convinced either way, but I think the actual user experience of using serde_rename with a bunch of special syntax might, to some extent, defeat the DX benefits of using something more "standard" like serde in the first place.

I use things like #[knus(children(name="route"))] incredibly often (where that filters the children of a node to those named "route", then parses each of those and collects them into a Vec<Route>), and I don't see how we'd emulate something like that in serde?

With that being said, I would really really like kdl-rs to have a derive macro — are you still open to that "evil plan" you mentioned over the holidays? KDL v2 -> KDL v1 -> Knus? Eventually, to be honest, I'd like kdl-rs to "eat" knus and for the derive macro to operate on the AST kdl-rs is already generating, but even that shorter-path solution would be beneficial, I think!

The major reason I'm using KDL over anything else is because it lets me create things that are slightly closer to DSLs than normal config files — I think it would be good if whatever derive-macro solution we integrate is just as flexible as KDL itself!

[zkat]

@TheLostLambda I have no idea, but @fasterthanlime recently expressed interest in trying to see if facet could be used instead of serde and was willing to take on that work? Just pinging him into this thread for reference.

[fasterthanlime]

@TheLostLambda I have no idea, but @fasterthanlime recently expressed interest in trying to see if facet could be used instead of serde and was willing to take on that work? Just pinging him into this thread for reference.

That is correct! I've been getting facet-json to near feature-completion and I'm excited to start work on KDL :)

[TheLostLambda]

I've just taken a look at @fasterthanlime 's stuff on facet and it looks insanely cool — I'm optimistic that the arbitrary attribute support (the stuff I've seen on the README for cli-arg parsing) should be exactly what we need to replicate things like knuss #[knus(children(name="route"))]!

I'm happy to lend a hand to anyone who'd like one here — now I'm also quite excited about facet 😅

[fasterthanlime]

I'm happy to lend a hand to anyone who'd like one here — now I'm also quite excited about facet 😅

Do you want to champion the facet-kdl efforts? I'll happily add you to the org so you can get stuff moving quickly.

I was excited to get it done but I don't feel ownership over actually doing it. I'm happy to step back and support you, making sure facet-core, facet-reflect etc. have what you need. Does that sound good?

[TheLostLambda]

@fasterthanlime I'd be super happy to give that a go! I'm sure KDL will be a lot more complex, but looking at some of the existing formats, I'm quite surprised at how easy facet makes some of it look!

I reckon it would be a really good use case for ironing out some of the arbitrary argument stuff :)

[fasterthanlime]

@fasterthanlime I'd be super happy to give that a go! I'm sure KDL will be a lot more complex, but looking at some of the existing formats, I'm quite surprised at how easy facet makes some of it look!

I reckon it would be a really good use case for ironing out some of the arbitrary argument stuff :)

Fantastic — let me stub out facet-kdl and add you to the org.

[fasterthanlime]

Fantastic — let me stub out facet-kdl and add you to the org.

Done in facet-rs/facet#358