Easy path to using anything with a ChainRulesCore.RuleConfig

[oxinabox]

We have talked about this before, just writing it down so it doesn't get lost.
The ChainRulesCore.RuleConfig with the right traits, provides all the parts needed for either getting the pushforward (frule_via_ad) or pullback (rrule_via_ad); or both.
This primitives are enough to let AbstractDifferentiation.jl define everything else.

Any ChainRules supporting AD that supports rules that require calling back into AD must define one of these.
Zygote.ZygoteRuleConfig and Diffractor.DiffractorRuleConfig for example.

Given such a RuleConfig type, it should be a one-liner to get the whole AbstractDifferentiation API.
We should provide a macro to make that so.

[gdalle]

I think this is now ReverseRuleConfigBackend?

[schlichtanders]

Is there some progress here?

[gdalle]

I think it should be ReverseRuleConfigBackend? Can you post a MWE if what you're trying does not work?

[oxinabox]

Yeah this is basically done.