Сергей, добрый день / Hi Sergey :
Переключаюсь на английский, чтоб мои ответы были понятны другим участникам / I am switching to English, so that my answer can be understood by other forum members.
The question is whether Agrest can create related objects together with the master object like this:
> {
> abc: "hello world",
> a: {
> qwerty: "abcdef"
> }
> }
This is a good one. Unfortunately currently the answer is "no", but I'd very much like it to happen and it is high on our TODO list. The biggest challenge so far is not the Java implementation, but defining or guessing proper semantics for all the possible cases of object sub-trees ("link", "create", "create-or-update"). I guess we just need to settle on good defaults.
Andrus